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Making Transportation Tunnels Safe and Secure (2006)

Chapter: Chapter 5 - Countermeasures

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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
×
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Suggested Citation:"Chapter 5 - Countermeasures." National Academies of Sciences, Engineering, and Medicine. 2006. Making Transportation Tunnels Safe and Secure. Washington, DC: The National Academies Press. doi: 10.17226/13965.
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Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

100 5.1 Introduction The main objective of this chapter is to identify and describe potential methods that can be used by tunnel own- ers and operators to make structural improvements (interior and exterior) and system improvements at critical locations for the purpose of improving the structural and operational security and safety of transportation tunnels and associated underground infrastructure (including stations, ventilation shafts, and electrical substations). 5.2 Hazard and Threat Directories Hazard and threat directories are tables that compile the hazard and threat scenarios for a particular tunnel mode (i.e., road, transit, or rail) and direct the user to the appropriate countermeasure guides (Tables 34 through 41), which con- tain more detailed information. 5.2.1 Structural Hazard and Threat Directories From the information contained in Section 4.4.2 (modes of tunnel failure) and Section 4.4.3 (effects of other extreme events), it was determined that explosives and large fires are the hazards and threats that must be considered when assess- ing structural vulnerability and damage potential. This find- ing, combined with other information contained in those sections, led to development of Table 28, which presents 13 hazard and threat scenarios within road tunnels that are con- sidered to be the most critical from a structural standpoint. Similarly, Tables 29 and 30 were developed to present 13 haz- ard and threat scenarios that are considered to be the most critical for transit and rail tunnels, respectively. In using Tables 28 through 30, the following steps should be performed: 1. Identify your tunnel by mode (road, transit, or rail) and choose the appropriate directory. 2. Identify your tunnel by “structural tunnel type” (immersed tube, cut-and-cover, bored or mined, air-rights structure), and eliminate the columns that don’t apply to your facility. 3. Review each of the “hazard or threat scenario” columns to identify and eliminate rows that don’t apply to your facil- ity. For example, within the “path to target” column you may eliminate the “waterway” rows if your tunnel is not underwater. 4. Make a list of countermeasure guides (i.e., Tables 34 through 41) that you need to review based on the remaining cells. 5.2.2 System Hazard and Threat Directories System hazard and threat directories were developed using information contained in Section 4.5.4 (potentially critical locations); Table 24 (vulnerabilities of critical locations); and Tables 25, 26, and 27 (system vulnerabilities to most likely hazard and threat scenarios for road, transit, and rail tunnels, respectively). These directories, presented as Tables 31, 32, and 33, show the hazard and threat scenarios that are consid- ered to be the most critical from a system standpoint for road, transit, and rail tunnels, respectively. The directories lead the user to more detailed information contained within the countermeasure guides, which are pre- sented as Tables 34 through 41. In using the system hazard and threat directories (Tables 31 through 33), the following steps should be performed: 1. Identify your tunnel by mode (road, transit, or rail), and choose the appropriate system hazard and threat directory. 2. Identify system types within your facility under “targeted system” (ventilation system, life safety system, power dis- tribution, command and control, and communications) to eliminate the columns that don’t apply to your facility. 3. Review each of the “hazard or threat scenario” columns to identify and eliminate rows that don’t apply to your facility. C H A P T E R 5 Countermeasures

epyT lennuT larutcurtS oiranecS taerhT ro drazaH .oN ro drazaH taerhT tegraT ot htaP yrevileD lacitcaT eciveD tegraT desremmI ebuT -dna-tuC revoC ro deroB ni deniM mriF ot tfoS dnuorG ro deroB ni deniM kcoR gnortS -riA sthgiR erutcurtS 1 A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL kcurT yawdaoR lennuT DEI egraL H muideM H2 DEI reniL naV/raC yawdaoR lennuT A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL kcapkcaB yawdaoR lennuT DEI llamS H3 eriF egraL H4 1 A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL reknaT yawdaoR lennuT /nmuloC kcurT yawdaoR lennuT DEI egraL H5 balS fooR/llaW 63 elbaT A/N A/N A/N A/N muideM H6 DEI /nmuloC naV/raC yawdaoR lennuT balS fooR/llaW 63 elbaT A/N A/N A/N A/N DEI llamS H7 /nmuloC kcapkcaB yawdaoR lennuT balS fooR/llaW 63 elbaT A/N A/N A/N A/N eriF egraL H8 1 /nmuloC reknaT yawdaoR lennuT balS fooR/llaW 63 elbaT A/N A/N A/N A/N eriF egraL H9 1 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT latroP reknaT yawdaoR lennuT 1 egraL yreV H0 DEI htpeD ro pihS yawretaW pihS morf egrahC tfahS ro latroP llaW 73 elbaT A/N 73 elbaT A/N 73 elbaT 11 egraL yreV H DEI morf egrahC htpeD yawretaW pihS A/N A/N 83 elbaT A/N 83 elbaT lennuT fo poT 1 ecafruS DEI egraL H2 revo yawdaoR lennuT 53 elbaT A/N A/N 53 elbaT A/N balS fooR kcurT 1 muideM H3 DEI ecafruS revo yawdaoR lennuT elpitluM ro kcurT skcapkcaB 53 elbaT A/N A/N 53 elbaT A/N balS fooR :etoN :noitaiverbbA elbacilppA toN = A/N 1 43 naht eroM . 1 ( ruoh rep UTBM 1 )WM 00 Table 28. Structural hazard and threat directory for road tunnels.

epyT lennuT larutcurtS oiranecS taerhT ro drazaH .oN ro drazaH taerhT tegraT ot htaP yrevileD lacitcaT eciveD tegraT desremmI ebuT -dna-tuC revoC ro deroB ni deniM mriF ot tfoS dnuorG ro deroB ni deniM kcoR gnortS -riA sthgiR erutcurtS 1 /raC tisnarT yawkcarT DEI egraL T enignE A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL muideM T2 DEI /raC tisnarT yawkcarT elpitluM ro enignE skcapkcaB A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL DEI llamS T3 /yawkcarT /spohS/snoitatS slatroP A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL kcapkcaB eriF egraL T4 1 tisnarT no DEI yawkcarT elciheV A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL tisnarT yawkcarT DEI egraL T5 enignE/raC /nmuloC balS fooR/llaW 63 elbaT A/N A/N A/N A/N muideM T6 DEI /raC tisnarT yawkcarT elpitluM ro enignE skcapkcaB /nmuloC balS fooR/llaW 63 elbaT A/N A/N A/N A/N DEI llamS T7 /yawkcarT /spohS/snoitatS slatroP /nmuloC kcapkcaB balS fooR/llaW 63 elbaT A/N A/N A/N A/N eriF egraL T8 1 tisnarT no DEI yawkcarT elciheV /nmuloC balS fooR/llaW 63 elbaT A/N A/N A/N A/N eriF egraL T9 1 tisnarT no DEI yawkcarT elciheV 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT latroP 1 egraL yreV T0 DEI htpeD ro pihS yawretaW pihS morf egrahC tfahS ro latroP llaW A/N 73 elbaT 73 elbaT A/N 73 elbaT 11 egraL yreV T DEI egrahC htpeD yawretaW pihS morf A/N A/N 83 elbaT A/N 83 elbaT lennuT fo poT 1 yawdaoR ecafruS DEI egraL T2 lennuT revo 53 elbaT A/N A/N 53 elbaT A/N balS fooR kcurT 1 muideM T3 DEI yawdaoR ecafruS lennuT revo elpitluM ro kcurT skcapkcaB 53 elbaT A/N A/N 53 elbaT A/N balS fooR :etoN :noitaiverbbA elbacilppA toN = A/N 1 43 naht eroM . 1 ( ruoh rep UTBM 1 )WM 00 Table 29. Structural hazard and threat directory for transit tunnels.

epyT lennuT larutcurtS oiranecS taerhT ro drazaH .oN ro drazaH taerhT tegraT ot htaP yrevileD lacitcaT eciveD tegraT desremmI ebuT -dna-tuC revoC ro deroB ni deniM mriF ot tfoS dnuorG ro deroB ni deniM kcoR gnortS -riA sthgiR erutcurtS 1 A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL enignE/raC liaR yawkcarT DEI egraL R muideM R2 DEI ro enignE/raC liaR yawkcarT skcapkcaB elpitluM A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL DEI llamS R3 /yawkcarT /spohS/snoitatS slatroP A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL kcapkcaB eriF egraL R4 1 A/N 43 elbaT 43 elbaT 43 elbaT 43 elbaT reniL elciheV liaR no DEI yawkcarT /llaW/nmuloC enignE/raC liaR yawkcarT DEI egraL R5 balS fooR 63 elbaT A/N A/N A/N A/N muideM R6 DEI ro enignE/raC liaR yawkcarT skcapkcaB elpitluM /llaW/nmuloC balS fooR 63 elbaT A/N A/N A/N A/N DEI llamS R7 /yawkcarT /spohS/snoitatS slatroP /llaW/nmuloC kcapkcaB balS fooR 63 elbaT A/N A/N A/N A/N eriF egraL R8 1 /llaW/nmuloC elciheV liaR no DEI yawkcarT balS fooR 63 elbaT A/N A/N A/N A/N eriF egraL R9 1 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT latroP elciheV liaR no DEI yawkcarT 1 egraL yreV R0 DEI htpeD ro pihS yawretaW pihS morf egrahC tfahS ro latroP llaW A/N 73 elbaT 73 elbaT A/N 73 elbaT 11 egraL yreV R DEI morf egrahC htpeD yawretaW pihS A/N A/N 83 elbaT A/N 83 elbaT lennuT fo poT 1 ecafruS DEI egraL R2 revo yawdaoR lennuT 53 elbaT A/N A/N 53 elbaT A/N balS fooR kcurT 1 muideM R3 DEI ecafruS revo yawdaoR lennuT elpitluM ro kcurT skcapkcaB 53 elbaT A/N A/N 53 elbaT A/N balS fooR :etoN :noitaiverbbA elbacilppA toN = A/N 1 43 naht eroM . 1 ( ruoh rep UTBM 1 )WM 00 Table 30. Structural hazard and threat directory for rail tunnels.

metsyS detegraT oiranecS taerhT ro drazaH .oN ro drazaH taerhT ot htaP tegraT lacitcaT eciveD yrevileD tegraT noitalitneV metsyS ytefaS efiL metsyS rewoP noitubirtsiD dnammoC lortnoC dna .smmoC 1 ecafruS DEI egraL H4 yawdaoR 93 elbaT 93 elbaT A/N A/N A/N retneC C&C kcurT 1 muideM H5 DEI ecafruS yawdaoR 93 elbaT 93 elbaT A/N A/N A/N retneC C&C naV/raC 1 ecafruS DEI llamS H6 yawdaoR kcapkcaB 2 93 elbaT 93 elbaT A/N A/N A/N retneC C&C 1 ecafruS DEI egraL H7 yawdaoR A/N A/N 93 elbaT A/N A/N noitatsbuS kcurT 1 muideM H8 DEI ecafruS yawdaoR A/N A/N 93 elbaT A/N A/N noitatsbuS naV/raC 1 ecafruS DEI llamS H9 yawdaoR kcapkcaB 2 A/N A/N 93 elbaT A/N A/N noitatsbuS ecafruS DEI egraL H02 yawdaoR erutcurtS .tneV kcurT 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT 21 muideM H DEI ecafruS yawdaoR erutcurtS .tneV naV/raC 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT ecafruS DEI llamS H22 yawdaoR kcapkcaB 2 erutcurtS .tneV 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT lennuT DEI egraL H32 yawdaoR ro evobA retneC C&C kcurT lennuT eht ot tnecajdA 43 elbaT 43 elbaT A/N A/N A/N muideM H42 DEI lennuT yawdaoR ro evobA retneC C&C naV/raC lennuT eht ot tnecajdA 43 elbaT 43 elbaT A/N A/N A/N lennuT DEI egraL H52 yawdaoR ro evobA erutcurtS .tneV kcurT lennuT eht ot tnecajdA 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT muideM H62 DEI lennuT yawdaoR ro evobA erutcurtS .tneV naV/raC lennuT eht ot tnecajdA 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT Table 31. System hazard and threat directory for road tunnels.

metsyS detegraT oiranecS taerhT ro drazaH .oN ro drazaH taerhT ot htaP tegraT lacitcaT eciveD yrevileD tegraT noitalitneV metsyS ytefaS efiL metsyS rewoP noitubirtsiD dnammoC lortnoC dna .smmoC lennuT DEI llamS H72 yawdaoR 43 elbaT 43 elbaT 43 elbaT A/N A/N knabtcuD desopxE kcapkcaB eriF egraL H82 1 lennuT yawdaoR latroP reknaT 4 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT eriF egraL H92 1 lennuT yawdaoR noitacoL lennuT ynA reknaT ytilicaF lacitirC ot tnecajdA 5 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT lennuT taMzaH H03 yawdaoR 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT noitacoL lennuT ynA kcurT 31 lennuT R/B/C H yawdaoR /losoreA/laiV egakcaP 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT stnapuccO lennuT lennuT R/B/C H23 riA ylppuS metsyS /losoreA/laiV egakcaP egrahcsiD dna lennuT stnapuccO aerA emulP A/N A/N A/N A/N 04 elbaT lennuT R/B/C H33 riA ylppuS metsyS /losoreA/laiV egakcaP egrahcsiD dna lennuT stnapuccO aerA emulP A/N A/N A/N A/N 04 elbaT rebyC H43 kcattA suriV latigiD lautriV edoC 4 elbaT A/N A/N A/N retneC C&C 1 A/N :setoN :snoitaiverbbA noitalitneV = .tneV snoitacinummoC = .smmoC lortnoC dna dnammoC = C&C lacigoloidaR/lacigoloiB/lacimehC = R/B/C lairetaM suodrazaH = taMzaH elbacilppA toN = A/N 1 43 naht eroM . 1 ( ruoh rep UTBM 1 )WM 00 edisni steg rotarteprep semussA .2 noitacol lartnec ni desuoh si snaf htiw lanidutignol ro metsys esrevsnart semussA .3 lennut lanoitceridinu ,llihnwod si esac tsroW .4 sretnec C&C ro srotareneg ycnegreme ,snoitatsbus ,sgnidliub noitalitnev sa hcuS .5 Table 31. (Continued).

metsyS detegraT oiranecS taerhT ro drazaH .oN ro drazaH taerhT ot htaP tegraT lacitcaT eciveD yrevileD tegraT noitalitneV metsyS ytefaS efiL metsyS rewoP noitubirtsiD dnammoC lortnoC dna .smmoC 1 ecafruS DEI egraL T4 yawdaoR 93 elbaT 93 elbaT A/N A/N A/N retneC C&C kcurT 1 muideM T5 DEI ecafruS yawdaoR 93 elbaT 93 elbaT A/N A/N A/N retneC C&C naV/raC 1 ecafruS DEI llamS T6 yawdaoR kcapkcaB 2 93 elbaT 93 elbaT A/N A/N A/N retneC C&C 1 ecafruS DEI egraL T7 yawdaoR A/N A/N 93 elbaT A/N A/N noitatsbuS kcurT 1 muideM T8 DEI ecafruS yawdaoR A/N A/N 93 elbaT A/N A/N noitatsbuS naV/raC 1 ecafruS DEI llamS T9 yawdaoR kcapkcaB 2 A/N A/N 93 elbaT A/N A/N noitatsbuS ecafruS DEI egraL T02 yawdaoR erutcurtS .tneV kcurT 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT 21 muideM T DEI ecafruS yawdaoR erutcurtS .tneV naV/raC 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT ecafruS DEI llamS T22 yawdaoR erutcurtS .tneV kcapkcaB 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT ecafruS DEI egraL T32 yawdaoR 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT noitatS kcurT ecafruS DEI llamS T42 yawdaoR kcapkcaB 2 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT noitatS ro knabtcuD desopxE kcapkcaB yawkcarT DEI llamS T52 tnempiuqE CEM 43 elbaT 43 elbaT 43 elbaT 43 elbaT A/N kcapkcaB yawkcarT DEI llamS T62 2 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT noitatS Table 32. System hazard and threat directory for transit tunnels.

metsyS detegraT oiranecS taerhT ro drazaH .oN ro drazaH taerhT ot htaP tegraT lacitcaT eciveD yrevileD tegraT noitalitneV metsyS ytefaS efiL metsyS rewoP noitubirtsiD dnammoC lortnoC dna .smmoC eriF egraL T72 1 yraidnecnI yawkcarT niarT no eciveD latroP 2 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT eriF egraL T82 1 yraidnecnI yawkcarT niarT no eciveD noitacoL lennuT ynA lacitirC ot tnecajdA ytilicaF 5 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT suodrazaH T92 slairetaM 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT noitacoL lennuT ynA niarT no eciveD yawkcarT /losoreA/laiV yawkcarT R/B/C T03 no egakcaP niarT 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT stnapuccO noitatS/lennuT 31 riA lennuT R/B/C T ylppuS metsyS /losoreA/laiV egakcaP dna noitatS/lennuT aerA emulP egrahcsiD stnapuccO A/N A/N A/N A/N 04 elbaT riA lennuT R/B/C T23 ylppuS metsyS /losoreA/laiV egakcaP dna noitatS/lennuT aerA emulP egrahcsiD stnapuccO A/N A/N A/N A/N 04 elbaT rebyC T33 kcattA suriV latigiD lautriV edoC 4 elbaT A/N A/N A/N retneC C&C 1 A/N :setoN :snoitaiverbbA noitalitneV = .tneV snoitacinummoC = .smmoC lortnoC dna dnammoC = C&C lacigoloidaR/lacigoloiB/lacimehC = R/B/C lairetaM suodrazaH = taMzaH elbacilppA toN = A/N 1 43 naht eroM . 1 ( ruoh rep UTBM 1 )WM 00 edisni steg rotarteprep semussA .2 noitacol lartnec ni desuoh si snaf htiw lanidutignol ro metsys esrevsnart semussA .3 lennut lanoitceridinu ,llihnwod si esac tsroW .4 sretnec C&C ro srotareneg ycnegreme ,snoitatsbus ,sgnidliub noitalitnev sa hcuS .5 Table 32. (Continued).

metsyS detegraT oiranecS taerhT ro drazaH .oN ro drazaH taerhT ot htaP tegraT lacitcaT eciveD yrevileD tegraT noitalitneV metsyS ytefaS efiL metsyS rewoP noitubirtsiD dnammoC lortnoC dna .smmoC 1 ecafruS DEI egraL R4 yawdaoR 93 elbaT 93 elbaT A/N A/N A/N retneC C&C kcurT 1 muideM R5 DEI ecafruS yawdaoR 93 elbaT 93 elbaT A/N A/N A/N retneC C&C naV/raC 1 ecafruS DEI llamS R6 yawdaoR kcapkcaB 2 93 elbaT 93 elbaT A/N A/N A/N retneC C&C 1 ecafruS DEI egraL R7 yawdaoR A/N A/N 93 elbaT A/N A/N noitatsbuS kcurT 1 muideM R8 DEI ecafruS yawdaoR A/N A/N 93 elbaT A/N A/N noitatsbuS naV/raC 1 ecafruS DEI llamS R9 yawdaoR kcapkcaB 2 A/N A/N 93 elbaT A/N A/N noitatsbuS ecafruS DEI egraL R02 yawdaoR erutcurtS noitalitneV kcurT 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT 21 muideM R DEI ecafruS yawdaoR erutcurtS noitalitneV naV/raC 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT ecafruS DEI llamS R22 yawdaoR kcapkcaB 2 erutcurtS noitalitneV 3 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT ecafruS DEI egraL R32 yawdaoR 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT noitatS kcurT ecafruS DEI llamS R42 yawdaoR kcapkcaB 2 93 elbaT 93 elbaT 93 elbaT 93 elbaT 93 elbaT noitatS ro knabtcuD desopxE kcapkcaB yawkcarT DEI llamS R52 tnempiuqe CEM 43 elbaT 43 elbaT 43 elbaT 43 elbaT A/N kcapkcaB yawkcarT DEI llamS R62 2 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT noitatS Table 33. System hazard and threat directory for rail tunnels.

metsyS detegraT oiranecS taerhT ro drazaH .oN ro drazaH taerhT ot htaP tegraT lacitcaT eciveD yrevileD tegraT noitalitneV metsyS ytefaS efiL metsyS rewoP noitubirtsiD dnammoC lortnoC dna .smmoC eriF egraL R72 1 yraidnecnI yawkcarT niarT no eciveD latroP 4 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT eriF egraL R82 1 yraidnecnI yawkcarT niarT no eciveD noitacoL lennuT ynA lacitirC ot tnecajdA ytilicaF 5 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT suodrazaH R92 slairetaM 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT noitacoL lennuT ynA niarT no eciveD yawkcarT /losoreA/laiV yawkcarT R/B/C R03 no egakcaP niarT 43 elbaT 43 elbaT 43 elbaT 43 elbaT 43 elbaT stnapuccO noitatS/lennuT 31 riA lennuT R/B/C R ylppuS metsyS /losoreA/laiV egakcaP dna noitatS/lennuT aerA emulP egrahcsiD stnapuccO A/N A/N A/N A/N 04 elbaT riA lennuT R/B/C R23 ylppuS metsyS /losoreA /laiV egakcaP dna noitatS/lennuT aerA emulP egrahcsiD stnapuccO A/N A/N A/N A/N 04 elbaT rebyC R33 kcattA suriV latigiD lautriV edoC 4 elbaT A/N A/N A/N retneC C&C 1 A/N :setoN :snoitaiverbbA noitalitneV = .tneV snoitacinummoC = .smmoC lortnoC dna dnammoC = C&C lacigoloidaR/lacigoloiB/lacimehC = R/B/C lairetaM suodrazaH = taMzaH elbacilppA toN = A/N 1 43 naht eroM . 1 ( ruoh rep UTBM 1 )WM 00 edisni steg rotarteprep semussA .2 noitacol lartnec ni desuoh si snaf htiw lanidutignol ro metsys esrevsnart semussA .3 lennut lanoitceridinu ,llihnwod si esac tsroW .4 sretnec C&C ro srotareneg ycnegreme ,snoitatsbus ,sgnidliub noitalitnev sa hcuS .5 Table 33. (Continued).

110 Hazard or Threat Scenario Nos.: 1H-4H, 9H, 23H-31H; 1T-4T, 9T, 25T-30T; 1R-4R, 9R, 25R-30R PV: insufficient tunnel liner thickness; inadequate tunnel cover; relative proximity of hazard or threat to liner OV: uncontrolled access of vehicles into tunnels; insufficient vehicle inspections and/or cargo restrictions DP: tunnel collapse requiring up to several months to repair; rapid flooding and inflow of granular backfill material for underwater tunnels; total or partial loss of system function CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple-Benefit Potential CM # Lighting H M P DR Anti-Theft, Safety 1 Ventilation System H VH P, Op M Safety 2 Fire Detection System M L P DT Safety 3 Fire Protection System H H P, Op M Safety 4 CCTV System or CCVE H M P, Op DT, I Traffic Surveillance 5 Security Awareness Training H L Op DT, M 6 Roving Patrols M L Op DR, DT, I Safety, Security 7 HazMat Restrictions L L Op DR Safety, Security 8 Background Checks L L Op DR, DT Identify Unqualified Employees 9 ser usae M m u mi ni M Full-Scale Emergency Response Exercises H L Op DT, I, M 19 Guards at Portals H L Op DR, DT, I Public Assurance 20 Inspections (Personal/Vehicle) H L Op DR, DT, I Public Assurance 21 Bomb-Sniffing Dogs M L Op DR, DT Public Assurance 22 Onsite Credential Checks L L Op DR Anti-Theft 23 M ea su re s fo r an E le va te d Th re at L ev el Explosive Detectors—Mobile H L P DT 26 Explosive Detectors—Fixed H M P DT 28 Interior Liner Steel Plates or Panels1,2,3 H VH 6 P M 31 Interior Liner Concrete Panels1,2 H VH 6 P M 32 Interior Concrete or Chemical Grouting M 4 VH6 P M 33 Interior Liner Bolting or Tie- Backs1,2 M 4 H6 P M 34 Exterior (Ground) Concrete or Chemical Grouting H 4 VH P M Decrease Maintenance, Increase Usable Life of Structure 35 Rip-Rap over Tunnel5 H VH P M Erosion Protection 36 Precast Concrete Slab over Tunnel5 H VH P M Erosion Protection 37 st ne mec nah nE t ne na mreP Disperse Functions (i.e., Redundant Systems) H H P M Decrease Maintenance, Increase Usable Life of Systems Footnotes 1. If operating environment and/or clearances allow. 2. Thickness of steel plates or panels, concrete panels, and shotcrete depends on size of IED or fire. 3. For very large fires, steel liner must be one continuous, seamless plate and attaching mechanisms must be fire- resistant. 4. Effectiveness will depend on surrounding soil properties. 5. Underwater tunnel only—amount of rip-rap and thickness of concrete slab depends on size of IED. 6. Cost may increase due to low-clearance applications, electrified transit and rail tunnels, track outage durations, bonding, and grounding. Table 34. Countermeasure guide.

Hazard or Threat Scenario Nos.: 12H, 13H; 12T, 13T; 12R, 13R PV: insufficient roof slab thickness; inadequate tunnel cover; relative proximity of hazard or threat to roof slab OV: uncontrolled access of vehicles into tunnels; insufficient vehicle inspections and/or cargo restrictions DP: tunnel collapse requiring up to several months to repair; total or partial loss of system function CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple-Benefit Potential CM # Lighting H M P DR Anti-Theft, Safety 1 Ventilation System H VH P, Op M Safety 2 Fire Detection System M L P DT Safety 3 Fire Protection System H H P, Op M Safety 4 CCTV System or CCVE H M P, Op DT, I Traffic Surveillance 5 Security Awareness Training H L Op DT, M 6 Roving Patrols M L Op DR, DT, I Safety, Security 7 HazMat Restrictions L L Op DR Safety, Security 8 Background Checks L L Op DR, DT Identify Unqualified Employees 9 ser usae M m u mi ni M Full-Scale Emergency Response Exercises H L Op DT, I, M 19 Guards at Portals H L Op DR, DT, I Public Assurance 20 Inspections (Personal/Vehicle) H L Op DR, DT, I Public Assurance 21 Bomb-Sniffing Dogs M L Op DR, DT Public Assurance 22 Onsite Credential Checks L L Op DR Anti-Theft 23 Explosive Detectors—Mobile H L P DT 26 Explosive Detectors—Fixed H M P DT 28 Interior Roof Steel Plates1,2 H VH P M 38 Interior Roof Concrete Panels1,2 H VH P M 39 Exterior Roof Steel Plates1,2 H VH P M 40 Exterior Roof Concrete Panels1,2 H VH P M Decrease Maintenance, Increase Usable Life of Structure 41 st ne mec nah nE t ne na mreP Disperse Functions (i.e., Redundant Systems) H H P M Decrease Maintenance, Increase Usable Life of Systems Footnotes 1. If operating environment and/or clearances allow. 2. Thickness of steel plates or panels, concrete panels, and shotcrete depends on size of IED or fire. 3. Effectiveness will depend on surrounding soil properties. 4. Underwater tunnel only—amount of rip-rap and thickness of concrete slab depends on size of IED. 5. Cost may increase due to low-clearance applications, electrified transit and rail tunnels, track outage durations, bonding, and grounding. M ea su re s fo r an E le va te d Th re at L ev el Table 35. Countermeasure guide. 111

112 Hazard or Threat Scenario Nos.: 5H-8H; 5T-8T; 5R-8R PV: insufficient column/wall/roof slab protection within air-rights structure OV: uncontrolled access of vehicles into tunnels; insufficient vehicle inspections and/or cargo restrictions DP: extensive column/wall/roof slab damage requiring up to several months to repair; total or partial loss of system function CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple-Benefit Potential CM # Lighting H M P DR Anti-Theft, Safety 1 Ventilation System H VH P, Op M Safety 2 Fire Detection System M L P DT Safety 3 Fire Protection System H H P, Op M Safety 4 CCTV System or CCVE H M P, Op DT, I Traffic Surveillance 5 Security Awareness Training H L Op DT, M 6 Roving Patrols M L Op DR, DT, I Safety, Security 7 HazMat Restrictions L L Op DR Safety, Security 8 Background Checks L L Op DR, DT Identify Unqualified Employees 9 ser usae M m u mi ni M Full-Scale Emergency Response Exercises H L Op DT, I, M 19 Guards at Portals H L Op DR, DT, I Public Assurance 20 Inspections (Personal/Vehicle) H L Op DR, DT, I Public Assurance 21 Bomb-Sniffing Dogs M L Op DR, DT Public Assurance 22 Onsite Credential Checks L L Op DR Anti-Theft 23 Explosive Detectors—Mobile H L P DT 26 Explosive Detectors—Fixed H M P DT 28 Interior Roof Steel Plates1,2 H VH P M 38 Interior Roof Concrete1,2 Panels H VH P M 39 Bollards to Control Access H L P DR, DT 42 Fencing to Control Access H L P DR, DT Pedestrian and User Safety, Anti- Trespassing 43 Concrete Encasement1,2 of Columns M L P M 44 RFP Wrapping1,2 of Columns M L P M 45 Steel Jacketing1,2 of Columns M L P M 46 Redundant Columns or Walls1,2 H H P M Decrease Maintenance, Increase Usable Life of Structure 47 st ne mec nah nE t ne na mreP Disperse Functions (i.e., Redundant Systems) H H P M Decrease Maintenance, Increase Usable Life of Systems Footnotes 1. If operating environment and/or clearances allow. 2. Thickness of steel plates or panels, concrete panels, and shotcrete depends on size of IED or fire. 3. Effectiveness will depend on surrounding soil properties. 4. Underwater tunnel only—amount of rip-rap and thickness of concrete slab depends on size of IED. 5. Cost may increase due to low-clearance applications, electrified transit and rail tunnels, track outage durations, bonding, and grounding. M ea su re s fo r an E le va te d Th re at L ev el Table 36. Countermeasure guide.

113 Hazard or Threat Scenario Nos.: 1 0H; 1 0T; 1 0R PV: insufficient portal/shaft wall strength OV: uncontrolled water traffic; insufficient ship inspections and surveillance DP: tunnel collapse causing operational disruption and requiring up to several weeks to repair; rapid flooding if portal/shaft wall is close to the water CV Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple-Benefit Potential CM # Background Checks L L Op DR, DT Identify Unqualified Employees 9 m u m i n i M s e r u s a e M Full-Scale Emergency Response Exercises H L Op DT, I, M 1 9 Inspections (Personal/Vehicle) H L Op DR, DT, I Safety 2 1 Bomb-Sniffing Dogs M L Op DR, DT, I Public Assurance 22 Onsite Credential Checks L L Op DR, DT Anti-Trespassing 23 Waterborne Patrols M L Op DR, DT, I Safety 24 Ship-Tracking Protocols M L Op DT Dock Scheduling 25 Interior Liner Steel Plates or Panels 1 ,2,4 H VH 6 P M 3 1 Interior Liner Concrete Panels 1 ,2 H VH 6 P M 32 Interior Concrete or Chemical Grouting M 5 VH 6 P M 33 Interior Liner Bolting or Tie-Backs 1 ,2 M 5 H 6 P M Decrease Maintenance, Increase Usable Life of Structure 34 Exterior (Ground) Concrete or Chemical Grouting H 5 VH P M Decrease Maintenance, Increase Usable Life of Structure 35 Floodgates 1 ,7 M VH 6 P M 48 Barrier Walls 3 H H P DR, M Increase Usable Life of Structure 49 s t n e m e c n a h n E t n e n a m r e P Bollards 3 or Fenders in the Water H H P DR, M Increase Usable Life of Structure 50 Footnotes 1 . If operating environment and/or clearances allow. 2. Thickness of steel plates or panels, concrete panels, and shotcrete depends on size of IED or fire. 3. Thickness of barrier walls, bollards, or fender system depends on size of IED and distance of portal/shaft wall to water traffic. 4. For very large fires, steel liner must be one continuous, seamless plate and the attaching mechanisms must be fire- resistant. 5. Effectiveness will depend on surrounding soil properties. 6. Cost may increase due to low-clearance applications, electrified transit and rail tunnels, track outage durations, bonding, and grounding. 7. Effectiveness will depend on physical dimensions of the tunnel. M ea su re s fo r an E le va te d Th re at L ev el Table 37. Countermeasure guide.

114 M ea su re s fo r an E le va te d Th re at L ev el Hazard or Threat Scenario Nos.: 11H; 11T; 11R PV: insufficient strength of tunnel top OV: uncontrolled water traffic; insufficient ship inspections and surveillance DP: tunnel collapse causing operational disruption and requiring up to several weeks to repair; rapid flooding if portal/shaft wall is close to the water CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple-Benefit Potential CM # Background Checks L L Op DR, DT Identify Unqualified Employees 9mu mi ni M ser usae M Full-Scale Emergency Response Exercises H L Op DT, I, M 19 Inspections (Personal/Vehicle) H L Op DR, DT, I Safety 21 Bomb-Sniffing Dogs M L Op DR, DT, I Public Assurance 22 Onsite Credential Checks L L Op DR, DT Anti-Trespassing 23 Waterborne Patrols M L Op DR, DT, I Safety 24 Ship-Tracking Protocols M L Op DT Dock Scheduling 25 Interior Liner Steel Plates or Panels1,2,3 H VH 5 P M 31 Interior Liner Concrete Panels1,2 H VH 5 P M 32 Interior Concrete or Chemical Grouting M 4 VH5 P M 33 Interior Liner Bolting or Tie-Backs1,2 M 4 H5 P M Decrease Maintenance, Increase Usable Life of Structure 34 Rip-Rap over Tunnel7 H H P M Erosion Protection 36 Precast Concrete Slab over Tunnel7 H H P M Erosion Protection 37 st ne mec nah nE t ne na mreP Floodgates1,6 M VH5 P M 48 Footnotes 1. If operating environment and/or clearances allow. 2. Thickness of steel plates or panels, concrete panels, and shotcrete depends on size of IED or fire. 3. For very large fires, steel liner must be one continuous, seamless plate and the attaching mechanisms must be fire- resistant. 4. Effectiveness will depend on surrounding soil properties. 5. Cost may increase due to low-clearance applications, electrified transit and rail tunnels, track outage durations, bonding, and grounding. 6. Effectiveness will depend on physical dimensions of the tunnel. 7. Amount of rip-rap and thickness of concrete slab depend on size of IED. Table 38. Countermeasure guide.

M ea su re s fo r an E le va te d Th re at L ev el Hazard or Threat Scenario Nos.: 14H-22H; 14T-24T; 14R-24R PV: insufficient perimeter protection of critical structure OV: insufficient surveillance of critical structure DP: total or partial loss of system function CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple-Benefit Potential CM # Lighting H L P DR Anti-Theft, Safety 1 Ventilation System H M P, Op M Safety 2 Fire Detection System M L P DT Safety 3 Fire Protection System H H P, Op M Safety 4 CCTV System or CCVE H M P, Op DT, I Traffic Surveillance 5 Security Awareness Training H L Op DT, M 6 Roving Patrols M L Op DR, DT, I Safety, Security 7 HazMat Restrictions L L Op DR Safety, Security 8 Access Controls (Bollards, Fences, Walls, Locks) H L P DR, DT Pedestrian and User Safety, Anti- Trespassing 10 Employee Identification System H L P DR Work Hour Tracking 11 Intrusion Detection System H M P DT, I Anti-Trespassing 12 Evacuation Protocols L H Op M Applicable to Any Hazard 13 ser usae M m u mi ni M Full-Scale Emergency Response Exercises H L Op DT, I, M 19 Inspections (Personal/Vehicle) H L Op DR, DT, I Public Assurance 21 Bomb-Sniffing Dogs M L Op DR, DT, I Public Assurance 22 Onsite Credential Checks H L Op DR, DT, I Anti-Trespassing 23 Explosive Detectors— Mobile H L P DT, I 26 Explosive Detectors— Fixed H M P DT, I 28 t ne na mreP st ne mec nah nE Disperse Functions (i.e., Operate Redundant Systems) H H P M Increase Usable Life of Systems Table 39. Countermeasure guide. 115

Hazard or Threat Scenario Nos.: 32H, 33H; 31T, 32T; 31R, 32R PV: insufficient perimeter protection of ventilation intakes with respect to C/B/R OV: insufficient surveillance of ventilation intakes with respect to C/B/R DP: loss of life; required decontamination of vent system and facility CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple- Benefit Potential CM # Lighting H L P DR, DT Traffic Safety 1 CCTV System or CCVE H M P, Op DT, I Traffic Surveillance 5 Security Awareness Training M L Op DT, I, M 6 Roving Patrols M L Op DR, DT, I Safety, Security 7 Access Controls (Bollards, Fences, Walls, Locks) M M P DR Safety 10 Intrusion Detection System H M P DT Anti-Trespassing 12 Extend/Heighten Supply Air Intakes H M P DT 14 ser usae M m u mi ni M Full-Scale Emergency Response Exercises H L Op DT, I, M 19 Inspections (Personal/Vehicles) H L Op DT Public Assurance 21 C/B/R Detectors—Mobile H M P DT 27 Access Controls (Concrete Walls) H L 1 P DR Safety 10 C/B/R Detectors—Fixed H M P DT 29 Redundant Ventilation Systems H VH P M Increase Usable Life of Systems 30 t ne na mreP st ne mec nah nE Integrate Ventilation System Operation with C/B/R Detectors H M Op M Footnote 1. Cost of wall depends on height and length. M ea su re s fo r an E le va te d Th re at L ev el Hazard or Threat Scenario Nos.: 34H; 33T; 33R PV: insufficient or outdated electronic protection software OV: insufficient or outdated electronic protection software DP: lost or inappropriate traffic and MEC equipment control CM Type CM Functions and Descriptions Relative Effectiveness Order-of- Magnitude Cost P/Op Strategy Multiple- Benefit Potential CM # Background Checks M L Op DR, DT 9 Anti-Virus Software H L P, Op I 15 Computer Firewalls H L P, Op I 16 Backup Manual Control of Systems H M P, Op M 17 ser usae M m u mi ni M Regularly Scheduled Data Backup H L Op M Protect Integrity of Data and Signals, Protect Investment in Digital Systems 18 Table 40. Countermeasure guide. Table 41. Countermeasure guide.

117 For example, within the “hazard or threat”column you may eliminate the “HazMat” row if restrictions are already in place in your tunnel. You may also be able to eliminate whole columns (for example, you may eliminate the “sub- station” column if you don’t have a substation). 4. Make a list of countermeasure guides (i.e., Tables 34 through 41) that you need to review based on the remaining cells. 5.3 Countermeasure Guides 5.3.1 Introduction The countermeasure guides (Tables 34 through 41) con- tain a great deal of information in a compressed amount of space. Each of these guides describes various countermea- sures that can be considered for a number of hazard or threat scenarios outlined in Tables 14 through 16 (structural vul- nerabilities to most likely hazard and threat scenarios) and Tables 25 through 27 (system vulnerabilities to most likely hazard and threat scenarios). For example, Table 34 groups together scenarios 1H–4H and 9H from Table 28, 1T–4T and 9T from Table 29, and 1R–4R and 9R from Table 30. All of these scenarios have common physical vulnerabilities (i.e., insufficient tunnel liner thickness, inadequate tunnel cover, and relative proximity of hazard or threat to liner), opera- tional vulnerabilities (i.e., uncontrolled access of vehicles into tunnels and insufficient vehicle inspections and/or cargo restrictions), and damage potentials (i.e., tunnel col- lapse requiring up to several months to repair, rapid flood- ing and inflow of granular backfill material for underwater tunnels, and total or partial loss of system function). Thus, the possible countermeasures for all of these scenarios are the same. For another example, Table 39 groups together sce- narios 14H–22H from Table 31, 14T–24T from Table 32, and 14R–24R from Table 33. All of these scenarios have common physical vulnerabilities (i.e., insufficient perimeter protec- tion of a critical facility), operational vulnerabilities (i.e., insufficient surveillance of a critical structure), and damage potentials (i.e., total or partial loss of system function). Thus, the possible countermeasures for all of these scenarios are the same. 5.3.2 Information Contained in Countermeasure Guides Text Above the Table The first line of text above the tables in each countermeasure guide identifies the applicable hazard or threat scenarios from the directories (Tables 28 through 33). This identification is a way to cross-reference application of specific countermea- sures to various hazard and threat scenarios. The second line summarizes the physical vulnerabilities (“PV” in the tables) of the scenarios. The third line summarizes the operational vul- nerabilities (“OV” in the tables) of the scenarios, and the fourth line summarizes the damage potential (“DP” in the tables) of a successful attack. Countermeasure Type In the first column, the countermeasures (“CMs” in the tables) are grouped into three categories: • Minimum measures, • Measures for an elevated threat level, and • Permanent enhancements. These categories were created on the basis of the current state of practice, the current method of thinking concerning physical security of a transportation asset, and a knowledge- able body of study concerning the physical and structural weaknesses of tunnel structures and systems. Minimum Measures. This category refers to physical, permanent measures and temporary, operational measures that should already be in place in every tunnel. These meas- ures may be required by local code or be widely accepted standard design and practice as designated by professional societies. The measures may represent the current state of practice in tunnel safety and security, born of lessons learned and a collective body of knowledge. The measures are above-average in efficiency and generally moderate in cost. These measures include • Lighting; • Ventilation system; • Fire detection system; • Fire protection system; • Closed-circuit television (CCTV) system or closed-circuit video equipment (CCVE); • Security awareness training; • Roving patrols; • HazMat restrictions; • Background checks (of employees and/or vendors); • Access controls (bollards, fences, walls, locks); • Employee identification system; • Intrusion detection system; • Evacuation protocols; • Extend/heighten supply air intakes; • Anti-virus software; • Computer firewalls; • Backup manual control of systems; • Regularly scheduled data backup; and • Full-scale emergency response exercises.

Measures for an Elevated Threat Level. These countermea- sures are temporary, normally operational measures designed to be implemented when the tunnel system faces an elevated threat level. The threat level would ordinarily be based on the general location of the tunnel or an actual threat directed at the facility.Typically, the credibility of a threat to a tunnel or the sur- rounding area is assessed by a law enforcement or intelligence agency and passed through to the tunnel owner or operator. The measures deployed under this category are opera- tional. They largely consist of personnel-specific actions that can be deployed quickly across any area of the tunnel and kept in place as long as desired. The measures are also portable and can be ended quickly once the elevated threat condition has passed. The costs for implementing these temporary meas- ures are variable and directly related to the level of increased presence and operations at the tunnel. The costs rise as the level of protection and the deployment durations increase. Countermeasures that are deployed for an elevated threat level normally provide a measure of public assurance. This public assurance aids to temper any loss of mission due to increased travel times through the tunnel or inconvenience due to temporary changes of routine while transiting the tunnel. Measures recommended for implementation during an elevated threat level include • Guards at portals; • Inspections (personal/vehicle/ship); • Bomb-sniffing dogs; • Onsite credential checks; • Waterborne patrols; • Ship-tracking protocols (in restricted areas); • Explosive detectors—mobile; and • C/B/R detectors—mobile. Permanent Enhancements. This category includes all structural and system alterations of the tunnel environment that are added to increase the safety and security of the tun- nel. Permanent enhancements are costly and require time to design and build. The sometimes significant alteration of the tunnel requires capital investment by the owner and cooper- ation of management to implement these measures. Permanent enhancements will often serve the dual benefit of extending the usable life of the tunnel structure and sup- port systems. The renovations and improvements to strengthen the structure or provide redundancy may decrease the need for future capital investment to mitigate the effects of use and age. The recommended measures include the following: • Explosive detectors—fixed; • C/B/R detectors—fixed; • Redundant ventilation systems; • Interior liner steel plates or panels; • Interior concrete panels; • Interior concrete or chemical grouting; • Exterior (ground) concrete or chemical grouting; • Interior liner bolting or tie-backs; • Rip-rap over tunnel; • Precast concrete slab over tunnel; • Interior roof steel plates; • Interior roof panels; • Exterior roof steel plates; • Exterior roof concrete panels; • Bollards to control access; • Fencing to control access; • Concrete encasement of columns; • RFP wrapping of columns; • Steel jacketing of columns; • Redundant columns or walls; • Floodgates; and • Disperse functions (i.e., redundant systems). Countermeasure Functions and Descriptions The second column within each table describes the coun- termeasure and its function. The range of countermeasures explored in this guide track closely to the hazards and threats identified in Chapter 2. The countermeasure guides do not address weather induced hazard scenarios that are common in certain areas, such as blizzards and floods, because a tun- nel owner or operator encountering serious weather events would already have a body of knowledge and practice that is best for the local situation. Patterns of weather induced dis- ruptions to a tunnel, if any, have been set by history. In addi- tion, countermeasures do not address weather events because such events cannot be deterred, deflected, or interdicted. Each listed countermeasure represents a general class of measures, where appropriate. There is some latitude regard- ing which specific measure from the class will be imple- mented. For example, in the class of lighting, the system chosen could be high-pressure sodium, low-pressure sodium, incandescent, or any other type of fixture to provide illumination to a given area. The lighting may be mounted to a pole or wall or hung from a mast arm. The lighting system may be placed 20 to 50 feet (6 to 15 meters) apart, depend- ing on the illumination requirements. The myriad of choices for the implementation may be settled only by a review of local conditions. The countermeasures listed will lead the user to a subsec- tion of measures for further exploration. The decision on which countermeasures should be implemented must be based on full knowledge of what currently exists in the tun- nel environment, as well as what local conditions dictate. 118

Relative Effectiveness The third column rates the relative effectiveness of the countermeasure as low (L), medium (M), or high (M). While the ratings assigned to the various countermeasures are based on many years of engineering expertise and past project experience, it must be pointed out that the rating system is subjective. This rating gives the likely effectiveness of the recom- mended countermeasure to secure the asset, improve the safety of the asset, or mitigate the damage potential of a suc- cessfully delivered disruption. The rating scale indicates how useful the countermeasure would be as a single-source measure. The effectiveness ratings are not intended to provide use- fulness of each countermeasure coupled or installed in tan- dem with others that appear on Tables 34 through 41. The ratings for the effectiveness of each countermeasure are based on the collective experience of the research team and their combined 200+ years of tunnel design, construction, and operation. The ratings are also drawn from the experience gained in other, current work, including that performed on behalf of the U.S. Department of Homeland Security and several state and regional authorities. Order-of-Magnitude Cost The fourth column gives an order-of-magnitude cost rang- ing from low (L; up to $1 million) to very high (VH; over $10 million). Again, the cost ratings are very subjective and depend on a number of variables, including tunnel length, tunnel construction type, construction materials, surround- ing earth geology and groundwater conditions, available clearances, and interruption of operations (e.g., lane closures, track outages, and disconnection of catenary and/or third rail power). The continuous operation of a facility is a primary goal of a tunnel owner or operator. Therefore, mitigation measures should be performed from the outside of the tun- nel as opposed to the inside whenever possible to avoid inter- ruption of ongoing operations. The order-of-magnitude costs of countermeasures are given as general guidance only because the implementation of any countermeasure is subject to local variables that can- not be accounted for in this guide. The local variables could make the cost higher or lower than the cost estimate. Simi- larly, if the tunnel operations and maintenance staff have the capability to install or implement certain countermeasures, the overall cost to the owner would be significantly decreased. The cost estimates are given in broad ranges to reflect the disparity in prices across the geographical areas of the 500+ tunnels in the United States. Labor costs, climate, equipment durability, and the purchasing power of the tunnel owner or operator can affect the prices paid to obtain the countermea- sures. The ranges are wide to ensure the suitability of this report for a nationwide audience. The cost estimates are based on reasonable assumptions of how many countermeasure items would likely be needed in a tunnel environment. Where possible, a direct comparison to a tunnel retrofit was applied. The collective experience of the research team was used in developing the cost estimates. The final cost of all countermeasures and mitigation would need to be established locally and be based on the actual conditions the tunnel owner or operator faces. In Tables 34 through 41, the cost estimate indicators are as follows: • Low (L)—Cost estimate to implement this countermea- sure in a tunnel system should not exceed $1 million. • Medium (M)—Cost estimate to implement this counter- measure in a tunnel system should range between $1 mil- lion and $3 million. • High (H)—Cost estimate to implement this countermea- sure in a tunnel system should range between $3 million and $10 million. • Very high (VH)—Cost estimate to implement this coun- termeasure in a tunnel system should exceed $10 million. Physical/Operational The fifth column of Tables 34 through 41 indicates whether the countermeasure is a physical measure (P), an operational measure (Op), or both. Physical measures are constructed or deployed in a set loca- tion and require some type of inspection, design, construc- tion, and maintenance activities. Physical countermeasures require planning before deployment (such as preparation of design and construction documents) so as to maximize effi- ciency and value in serving the safety and security needs of the tunnel asset. Operational measures use personnel and are flexible, dynamic to the fluidity of a hazard or threat, and mobile. Operational measures can be elevated or downgraded to match the level of hazard or threat anticipated. Strategy The sixth column of each table indicates the strategy or strategies of each countermeasure. The strategies have evolved and been refined over time in accordance with the work of the National Academy of Science, the U.S. Depart- ment of Homeland Security, and practitioners across the nation. The strategies are aligned with current thinking in the area of transportation risk and security, including the upcom- ing multimodal guide entitled, “Guide to Risk Management 119

120 of Multimodal Transportation Infrastructure,”which is being developed under NCHRP Project 20-59(17). Possible strategies are deterrence (DR), detection (DT), interdiction (I), and mitigation (M; including response and preparedness): • Deterrence (i.e., Deflection): This category identifies coun- termeasures with a sure strategic objective, namely making an asset so difficult to disrupt, or so costly to the intentional attacker, that any disruption is not attempted. This category may also include the owner or operators’ ability to present their asset as impervious to intentional harm, such that the attacker is diverted to explore another target or not attack at all. The concept of deterrence is not usable against natu- ral hazards. Hurricanes, blizzards, floods, and other acts of nature cannot be deterred from their natural course. • Detection: This category identifies countermeasures in which the owner or operator can recognize that a hazard or threat exists and can communicate that actual or perceived hazard or threat to responders. This category applies to countermeasures implemented to learn of a disruptive event. The methods, techniques, technology, and person- nel deployed to learn of a pending or actual incident may vary based on local conditions. The means of detection may range from the physical, including sensors and implanted devices, to the operational, including analysis of intelligence gleaned from various sources. The act of detection extends to natural disasters and other unintentional events as clearly as to events of nefari- ous origin. Use of technology to pinpoint an unusual weather event or a faulty pump that may flood a road is as applicable to detecting a hazard as the police officer on fixed post at the portal inspecting cargo and discovering an explosive. Each action is valid. • Interdiction: This category identifies countermeasures in which the owner or operator can meet a hazard or threat after it has begun the delivery process. The owner or oper- ator should have preestablished personnel and material resources that may immediately be deployed upon learn- ing of the hazard or threat, which may be en route, at the target, or in the process of being delivered. Interdiction most normally applies to intentional acts of disruption, such as an attacker or saboteur entering the asset. Interdic- tion is a less significant strategy in dealing with natural weather events or spontaneous hazards, such as equipment fires. • Mitigation: This category identifies countermeasures designed to lessen the damage potential of any successfully delivered hazard or threat. The wide-ranging measures that fall into this category include both strategic mitigation measures requiring forethought and planning and tactical mitigation measures conducted by on-scene responders. Strategic mitigation measures are long-range mitigation measures that require effort and resources well in advance of a potential or actual hazard or threat. These measures involve planning and preparation, which generally include – Institutional arrangements and plans or memoranda of understanding, – Communications or public outreach plans, – Interdiction plans for intentional acts, – Continuity of operations plan, – Emergency response and recovery plan, – Agency preparedness plan, – Agency mobilization plan, – Drill and exercise guide, and – Personal preparedness plans (for responding employees). Strategic mitigation measures with all of these compo- nents allow the tunnel operating agency to prepare and respond to any disruption as one unified body, so well- versed and well-practiced in the plans that it can take last- minute, on-the-spot actions. Strategic mitigation measures may also involve physi- cally improving an asset so that it is impervious to the impact of the hazard or threat deployed. For example, rein- forcing a tunnel with steel plates will make the tube better able to withstand a blast overpressure, fire, or derailed train. A full list of ideas to mitigate a hazard or threat by using physical improvements and design is discussed in Section 5.4. Tactical measures include an emergency response to the scene at the time of disruption. Rescuing people, diverting traffic, and activating backup equipment can restore the asset’s operations. The ability to mitigate the damage potential of a hazard or threat by preparedness or response depends on the institution’s ability to have well-planned, well-executed operational measures in place. These meas- ures will likely include the involvement of personnel and agencies beyond the jurisdiction of the tunnel owner or operator. The need for advanced planning and tactical coordination is crucial for the success of this tool to be employed as a mitigating measure against all hazards and threats. Some countermeasures have multiple strategies associated with them, such as bollards, which act as both deterrence and mitigation. Such countermeasures may receive higher prior- ity for this dual benefit. Multiple-Benefit Potential Many countermeasures have potential to provide other benefits besides increasing the safety and security of a tunnel.

Multiple-benefit potential may change the prioritization of countermeasures. For example, some mitigation measures can both decrease maintenance and increase the usable life of the structure. This dual benefit could lead to significant cost savings over the life of the structure. The identification of multiple-benefit potential is based on realistic expectations of what may be done with the countermeasure, including the following potential benefits: • Pedestrian safety, • Traffic surveillance, • Public assurance, • Anti-theft, • Anti-trespassing. • Detection of unqualified employees, • Decrease maintenance, • Increase usable life of system, • Erosion protection, • Protection of data integrity, • Protection of investment in data systems, and • Dock scheduling (for shipping). Countermeasure Number The last column of the countermeasure guides identifies the countermeasure number. Countermeasures 1 to 19 are recommended minimum measures and are described in detail in Section 5.4.1. Countermeasures 20 to 27 are recom- mended measures for an elevated threat conditions and are described in detail in Section 5.4.2. Countermeasures 28 through 50 are recommended perma- nent enhancements and are described in detail in Section 5.4.3. 5.3.3 How to Use the Countermeasure Guides The following steps should be followed in using the coun- termeasure guides (Tables 34 through 41): 1. Review the tables to further eliminate certain hazards and threats based on existing knowledge or inspection of countermeasures that are already in place or not possible based on restrictions such as operating environments and clearances. 2. Identify all possible countermeasures for your facility, and make a list of countermeasure numbers from the last col- umn of Tables 34 through 41 to be reviewed. 3. Study the relevant sketches and text in Sections 5.4.1, 5.4.2, and 5.4.3 to become familiar with the details involved. 4. Go back to Tables 34 through 41 to weigh relative effec- tiveness and order-of-magnitude costs of identified coun- termeasures. 5. Create a prioritized countermeasure list for your facility. 6. Consider multiple-benefit potential information to deter- mine if your list should be re-prioritized. 7. Study again the relevant sketches and text in Sections 5.4.1, 5.4.2, and 5.4.3, and finalize your priority list. If more detailed information than that provided herein is needed to justify a selection, an in-house or outside expert can be used to develop conceptual designs and associated costs of possible countermeasures. The following abbreviations and cost scales have been used throughout Tables 34 through 41: Text Above Tables PV = Physical Vulnerability OV = Operational Vulnerability DP = Damage Potential of a Successful Attack Column 3: Relative Effectiveness L = Low M = Medium H = High VH = Very High Column 4: Order-of-Magnitude Cost L = Low = up to $1 million M = Medium = between $1 million and $3 million H = High = between $3 million and $10 million VH = Very High = over $10 million Column 5: P/OP P = Physical Op = Operational Column 6: Strategy DR = Deter DT = Detect I = Interdict M = Mitigate (Includes Response and Preparedness) 5.4 Countermeasure Descriptions The following sections describe in detail the countermea- sures listed in the countermeasure guides. Since the continu- ous operation of a facility is a primary goal of a tunnel owner or operator, each of these mitigation measures should con- sider the effect that construction will have on operations. In some cases, the cost of service interruption may outweigh the cost of construction. Whenever possible, construction should be performed from the outside of the tunnel as opposed to the inside to avoid interruption of ongoing operations. Other considerations should include dynamic clearance envelopes 121

122 necessary for equipment types, methods of installation of countermeasures by contractors, presence of employees for maintenance and inspection, and use of the facilities by pas- sengers during emergencies. 5.4.1 Recommended Minimum Measures Countermeasure 1: Lighting Lighting provides a basic, reliable, and cost-effective safety and security measure. By providing visibility to all critical areas, lighting enables a monitor, controller, or law enforce- ment official to take the necessary preventive actions to deter an intentional threat or to detect a disruption that is occur- ring or has occurred in the tunnel environment. In addition, proper lighting allows for the safe evacuation of impacted tunnel users and employees during an emergency, simultane- ously assisting emergency responders arriving to the incident scene. This safe and efficient response is necessary for any dis- ruption, intentional or unintentional, including natural dis- asters. See Table 42. The cost of lighting schemes varies as a function of the level of illumination and the quality and quantity of lights installed. The mounting surface (i.e., wall or ceiling) will also affect the final cost. There are typical types of lighting fixtures and arrangements used in tunnel environments, and their proven histories can provide a reliable barometer for any new installation, upgrade, or retrofit. Countermeasure 2: Ventilation System The ventilation system is usually the most important life safety system in the tunnel. The type of ventilation system used in a tunnel can vary and is typically affected by the fol- lowing: • Tunnel mode or usage – Road – Transit – Passenger/freight rail • Construction methodology – Immersed tube – Cut-and-cover – Bored or mined – Air-rights structures • Tunnel attributes – Length – Shape – Occupancy loads – Location • Date of initial construction – In some cases, very old tunnels reflect the state of venti- lation technology at the time of construction To provide the best applicable ventilation system, the tun- nel owner or operator must conduct an examination of the current system, if installed, or as designed before construc- tion. This examination needs to include deference to the uses of the ventilation system to support the safety of the tunnel environment. A well-designed, well-maintained ventilation system can provide the means to direct and exhaust smoke or fouled, toxic air away from tunnel users involved in an inci- dent. The ventilation system effectively maintains or improves the safety of the tunnel. See Table 43. Tunnel ventilation systems require capital investments as well as assiduous maintenance programs to ensure their effectiveness. Countermeasure Description Installed, well-sited lighting system designed to provide illumination to all areas of the tunnel environment. Types/Components High-pressure sodium; low-pressure sodium; incandescent; luminescent. Use Roadway lights; area lighting; security lighting; access area lighting. Category Minimum measures. Strengths Visibility in all areas. Weaknesses Susceptible to power failure from external utility; possible misapplication of light for color CCTV applications. Rough Cost of Implementation Medium—$1 million to $3 million per tunnel. Cost depends on tunnel length and type of fixtures. Operation and Maintenance Installation and maintenance may be handled in-house. Training Requirements None. Life Expectancy Infrastructure: 20+ years; Lamps: 24,000 hours. Comments Cost varies widely by system size and utility work required. Electrical costs and lamp replacements every 1 to 3 years. Standard electrician can maintain system. Table 42. Countermeasure 1: Lighting.

123 Countermeasure 3: Fire Detection System Fire detection systems are sound investments for the safety and security of any tunnel system. An automated system capable of reaching all points within the tunnel environment will provide rapid notification of all smoke and flame condi- tions to a monitoring station, thereby triggering a rapid emer- gency response. See Table 44. The smoke and flame conditions may be the result of unin- tentional events, such as malfunctioning equipment or vehi- cles. Smoke and flame may also be the result of a disruptive event such as a derailment, collision, or explosion. They may also indicate a breakdown of another crucial tunnel system, or a breach of the tunnel integrity. Countermeasure 4: Fire Protection System Tunnel fire protection systems can provide a quick response to a smoke or flame condition, protecting tunnel users and the integrity of the tunnel structure. The type of protection chosen and installed will depend on the tunnel usage. Whereas a wet system might be appropriate for a high- way tunnel application, it would not be appropriate for an Countermeasure Description Provides airflow to and from the tunnel space. Types/Components Supply fans (blowers); exhaust fans; ducts; dampers; louvers; power source. Use Coverage of entire tunnel area. Category Minimum measures. Strengths Road tunnel systems can be used for non-emergency (i.e., normal) conditions to remove airborne impurities from the roadway. Weaknesses Requires sustained maintenance to maintain effectiveness. Rough Cost of Implementation Very high—over 10 million per tunnel. Cost depends on tunnel length and ventilation system type. Cost of Operations and Maintenance 15–25 percent. Training Requirements High—initial training of control center and maintenance staff, followed by annual incremental refreshers and/or updates. Life Expectancy 10–20 years. Comments Cost varies widely by system size and utility work required. Quality of system commensurate with cost. System may be upgraded from original, designed, and installed. Countermeasure Description Provides a fixed, continually operating series of sensors to detect a conflagration. Types/Components Flame detectors (ultraviolet or infrared); smoke sensors (ionization or light); heat sensors; one-button call systems for tunnel users; video monitoring; power source. Use Coverage of entire tunnel area. Category Minimum measures. Strengths Provides a rapid means of notification to emergency responders that a fire or smoke condition exists in the tunnel environment. Installed system is always operational and connected to monitoring facilities. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Cost depends on tunnel length. Operation and Maintenance Typically requires private contractor for monitoring and possible maintenance. Training Requirements Medium—initial training of control center and maintenance staff, followed by annual incremental refreshers and/or updates. System is intentionally automated. Life Expectancy 10–20 years. Comments Costs vary widely by system size and utility work required. Quality and cost of systems are fairly standard across all tunnel systems. Table 43. Countermeasure 2: Ventilation system. Table 44. Countermeasure 3: Fire detection system.

124 electrified transit or electrified rail tunnel. The most common type of tunnel fire protection system is the manually operated wet or dry standpipe. Automatic systems such as sprinklers and deluge systems (water-based or foam-based) and water mist systems are used, but are uncommon, particularly in the United States, which presently has only three road tunnels that use these technologies. The predominant criticism is the limited effectiveness of these systems, particularly for tunnel fires that begin inside a vehicle (car or train). Such fires con- stitute the majority of tunnel fires. Sprinklers, which have fusible links, must be directly over the heat sources to work. Deluge and water mist systems have open heads, so a high temperature or flame condition somewhere in the tunnel will activate the entire zone. At best, the water will cool down the fire and help to prevent its spread. At worst, the water will cre- ate panic in the tunnel and/or weigh down the smoke from the fire, bringing it closer to tunnel users. Annex D in NFPA 502 [Ref. 5] contains more information on the use of sprin- klers in road tunnels. See Table 45. The general term “fire protection” sometimes includes sys- tems, but may also include the establishment of permanent structures to aid in the evacuation and shelter of tunnel users in the event of an incident involving smoke or flame. The establishment of safe zones inside the tunnel, capable of pro- viding shelter from the smoke, flame, and heat, can provide safety to tunnel users awaiting rescue by emergency respon- ders. Clear evacuation routes with easy-to-understand dia- grams and signage would similarly assist tunnel users in fleeing a hazard or threat. Countermeasure 5: Closed-Circuit Television (CCTV) System or Closed-Circuit Video Equipment (CCVE) CCTV systems or CCVE provide the ability for a monitor to see inside the tunnel through real-time images trans- ferred along a secure pathway. The images are typically transmitted from cameras located at the tunnel portals or along the road or track bed to an operations control center, where the image is recorded or monitored by an operator. The CCTV or CCVE image may be shared with decision makers and emergency responders through a secure intranet. This technology is readily available and cost-effective. See Table 46. This transmission of images conveys the information nec- essary for immediate and appropriate response to any inci- dent scene (e.g., the safest path to approach and access the site, the conditions along the route, and what equipment and resources are required at the location). Countermeasure 6: Security Awareness Training Security awareness training provides a cornerstone of the owner or operator’s efforts to form a culture in their agency for security to complement longstanding, prevalent efforts in improving safety. A well-grounded training program may aim to indoctrinate new employees and educate existing employees in their potential to be front line detectors of abnormal people or activity that may lead to any disruption of the tunnel system. See Table 47. Providing employees with the proper tools to detect poten- tial security threats, borne of insufficient internal procedures or external threats, enables the owner or operator to prevent a disruption from occurring. Training programs are generally cost-efficient and -effective. Employees typically retain the transferred knowledge, and the message is uniformly distrib- uted to others. Training programs are flexible and can be altered to include new techniques and information as they develop. An effective training program should reflect the state of practice and the state of knowledge in the transportation and infrastructure security arena. Countermeasure Description Provides a fixed, continually operating series of distribution channels to combat a smoke or flame condition. Types/Components Wet standpipe; dry standpipe; sprinklers; deluge; water mist; fire extinguishers; evacuation pathways, cross-passages, and refuges; power source. Use Coverage of entire tunnel area. Category Minimum measures. Strengths Provides an immediate means of mitigating fire or smoke in the tunnel environment. Some installed systems can be automated. Weaknesses None. Rough Cost of Implementation High—between $3 million and $10 million per tunnel. Cost depends on tunnel length, system size, and utility work required. Operation and Maintenance Typically requires private contractor for maintenance. Training Requirements Medium—initial training of control center and maintenance staff, followed by annual incremental refreshers and/or updates. Life Expectancy 10–20 years. Comments Quality and cost of systems are fairly standard across all tunnels. Table 45. Countermeasure 4: Fire protection system.

125 Countermeasure 7: Roving Patrols Tunnel owners and operators may implement roving patrols to increase the level of safety and security vigilance. Patrols provide trained personnel, typically with police powers, to explore the areas in and around the tunnel struc- ture and support systems. The patrol personnel can act immediately to investigate any unusual or suspicious situa- tion and respond immediately to any hazard or threat. The usual staggered time delay associated with visits or rounds provides a layer of uncertainty to anyone intent on perpe- trating an intentional threat. However, patrols are excellent resources to interdict a hazard or threat and to lead a response. See Table 48. Roving patrols are flexible in application, and their num- bers can be increased or decreased quickly to match any per- ceived or actual hazard or threat. This flexibility is unmatched in any other countermeasure and limited only by the number and availability of trained personnel. The training of patrol personnel can be as comprehensive as desired by the tunnel owner or operator. Countermeasure 8: Hazardous Material (HazMat) Restrictions A common existing practice among tunnel owners and operators is the restriction of hazardous materials from being transported through the tunnel structure. This measure is typically enacted to protect the tunnel from explosion or con- tamination that may be caused by an accident or spill. The measure is an effective and low-cost way to protect tunnel users from a potentially harmful disaster. See Table 49. Restrictions on hazardous materials are generally adhered to in public-use tunnel systems, such as highway and transit. Countermeasure Description Provides a fixed, continually operating channel of video images to monitors and responders. Types/Components Cameras; monitoring stations; recording capacity; image-sharing capability; power source. Use Coverage of entire tunnel area. Category Minimum measures. Strengths Provides an immediate means of viewing conditions inside the tunnel environment using real-time video feed. Weaknesses Requires maintenance; systems can quickly become outdated. Rough Cost of Implementation Medium—between $1 million and $3 million per tunnel. Cost depends on tunnel length and coverage (i.e., number of cameras). Operation and Maintenance Maintenance may be handled by in-house personnel. Monitoring should be done by owner or operator’s staff. Training Requirements Medium—initial training of control center and maintenance staff required, followed by annual incremental refreshers and/or updates. Life Expectancy 5–10 years. Comments Quality and cost of systems are fairly standard across all tunnel systems. Countermeasure Description Modular based, instructor-led training program. Types/Components Module-based; initial training; annual refresher sessions. Use Required instruction for all tunnel employees. Category Minimum measures. Strengths Low-cost, effective method to teach all employees to be front line observers of unusual or suspicious behavior. Weaknesses Poor instruction may be transferred to employees. Quality control over instruction is necessary. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance None—measure is not mechanical. Training Requirements High—initial and refresher training of all employees is necessary. Life Expectancy 2–5 years. Comments The use of external consultants with credentials in tunnel security training may be expedient to the owner or operator. Table 46. Countermeasure 5: CCTV System or CCVE. Table 47. Countermeasure 6: Security awareness training.

126 Restrictions on the transport of hazardous materials to ensure their safe handling and passage may be employed so as to allow their passage through freight tunnels. Additional restrictions or required processing procedures may slow the progress of acceptable hazardous materials through the tun- nel, slowing commerce and perhaps having an economic impact on the community. Restrictions on hazardous materials are flexible measures that can be intensified or implemented with increased stan- dards during periods of elevated threat levels. In conjunction with vehicle inspections, hazardous material restrictions can be intensified to preclude materials from being transported through the tunnel to ensure that they cannot be used in an intentional attack. Countermeasure 9: Background Checks Tunnel owners and operators may conduct background checks of potential employees, vendors, and contractors. See Table 50. Conducting background checks of potential employees is a common practice to ensure that a candidate is qualified and free of criminal or suspicious associations. The investigations conform to local law and policy, including employee collec- tive bargaining agreements. Beyond the initial background investigation, updates are typically done for cause, without a set schedule. Investigations of vendors and contractor personnel are uncommon at this time. However, such investigations would provide an extra measure of safety and security. If vendors and contractor personnel are routinely provided unfettered access to the tunnel environment for the purpose of construction, maintenance, or delivery, then they represent a weak link in the security perimeter for that tunnel system. This weak link is more acute if the vendors or contractors can access the tun- nel without an escort from the owner or operator staff. Investigations of employees, vendors, and contractors may be as involved as desired by the owner or operator and as allowed by local law. They can range from cursory credit examinations to full-length background checks. The cost is Countermeasure Description Mobile police or private security patrols moving in and around the tunnel structure. Types/Components Police; private security; mobile; trained. Use Coverage of all tunnel areas. Category Minimum measures. Strengths Trained; mobile; flexible; rapidly deployable. Weaknesses Cost for extended service. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance None—measure is not mechanical. Training Requirements High—specialized, intense training of police and security personnel is required. Life Expectancy 2–5 years. Comments Countermeasure Description Restriction or exclusion of materials in the tunnel system. Types/Components Flammables; chemicals; corrosives; toxic; biological. Use Applicable to all tunnel areas. Category Minimum measures. Strengths Removes the hazard or threat from introduction into the tunnel, thereby eliminating a source of potential disruption. Weaknesses None to owner or operator. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance None—measure is not mechanical. Training Requirements Low—no special training is required for tunnel employees. Life Expectancy Lifetime. Comments Measure is flexible; more stringent standards may be implemented at short notice. Table 48. Countermeasure 7: Roving patrols. Table 49. Countermeasure 8: HazMat restrictions.

127 moderate, requiring only the active resource of in-house per- sonnel to perform the background investigations and to track the employees who have cleared this requirement. This meas- ure is also flexible, can be implemented to various degrees of specificity, and implemented with short notice, providing it is permissible under local statute and policy. Countermeasure 10: Access Controls (Bollards, Fences, Walls, Locks) Access control devices can provide an increased measure of security to fixed installations. The devices may be designed and installed to refuse entry to persons or items to a fixed location or to provide verification of individuals or equip- ment entering that location. The devices can be further divided into two categories, personnel access control and location access control. See Table 51. Personnel access control consists of systems that are designed and installed with the purpose of allowing only authorized persons into a facility. The facility is meant to be permeable. The access control devices authenticate users entering the fixed location by a variety of methods. There are many types of personnel access control devices available, including key cards matched with employment records, verification codes entered manually against a stored database, and biometric devices that measure body features and match them to individuals. Location access control devices are designed and installed to prevent all physical access near a location or into a facility. Location access control includes simple door locks, steel or concrete bollards, gates, hydraulic risers, and steel curtains. All access control devices provide an increased measure of security, but they are not infallible. A door lock can de defeated by a duplicate key. A computerized control system Countermeasure Description Examinations of the backgrounds of employees, vendors, and contractors to discern less-than-qualified individuals and obvious security risks. Types/Components Criminal database search; personal background investigation; credit evaluation. Use All new-hire employees, vendors, and contractors. Category Minimum measures. Strengths Reasonable cost to screen personnel with access to the tunnel system and discern questionable persons. Weaknesses Terms and restrictions may be subject to local law or collective bargaining agreements. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Measure is not mechanical; however, database tracking of screened personnel must be kept current. Training Requirements Low—no special training required for tunnel employees. Life Expectancy Lifetime. Comments Countermeasure Description Installation of mechanical and electronic devices to prevent unauthorized entry to tunnel areas. Types/Components Bollards; fences; locks; card swipe readers; proximity cards. Use All critical areas of tunnel or tunnel property. Category Minimum measures. Strengths Proven and available technology to secure an area from casual intrusion. Weaknesses Systems can be defeated. Rough Cost of Implementation Low—less than $1 million. Cost of wall depends on height and length. Operation and Maintenance System requires regular maintenance. Training Requirements Low—no special training required for tunnel employees. Life Expectancy Lifetime. Comments Table 50. Countermeasure 9: Background checks. Table 51. Countermeasure 10: Access controls (bollards, fences, walls, locks).

128 can be hacked, and overrides can be set in place. Physically, a bollard or fence can be overcome by a superior force exerting pressure. Access control designs can be flawed (allowing for a missing link of coverage) or poorly maintained (rendering them useless). Access control devices designed for a singular purpose and staff can be misapplied. There are five basic types of walls: • The gravity wall gets its stability entirely from the weight of masonry and any soil resting thereon. This wall must be of sufficient thickness to resist the forces acting on them without developing tensile stresses. Concrete gravity walls usually contain a nominal amount of reinforcement near the exposed surfaces to control temperature cracking. • The semi-gravity wall has largely supplanted the gravity wall because it is more slender and thus uses less material. However, the semi-gravity wall requires more vertical rein- forcement along the inner face and into the footings to resist the rather small tensile forces that develop in these locations. • The cantilever wall is a very common type of wall that con- sists of a base slab and a stem that are fully reinforced to resist the moments and shears to which they are subjected. • The counterfort wall consists of a relatively thin concrete slab that is supported by vertical counterforts connected to the base at intervals on the back side. • The crib wall is usually formed by rectangular elements or cells stacked on top of one another and filled with soil. Countermeasure 11: Employee Identification System Another measure to prevent trespassing in the tunnel areas is the implementation of an employee identification system. The systems, now common in many workplaces, may include the use of photo identification or data codes assigned to each employee. To enter a work area, the employee would be required to display his or her identification and have it accepted by the security monitor or access control device. See Table 52. Employee identification systems have proven to be as effec- tive as their level of maintenance and upkeep. Many programs are deficient in tracking the employee throughout his or her work life and particularly deficient at repossessing and/or deactivating identification cards after employees are trans- ferred to other assignments or after employees cease to work for the employer. A highly evolved program should have measures, policies, and procedures in place to reclaim the identification cards of inactive employees and electronically deactivate their permission to enter tunnel work areas. This accountability loop will maintain the integrity of the employee identifica- tion system. Countermeasure 12: Intrusion Detection System Intrusion detection systems (IDSs) are technologically advanced means of monitoring entry across large areas using minimal resources. Recent advances in technology provide a wide array of choices for implementing this measure. Most IDSs are small, power-saving devices that are capable of being linked together and with central monitoring stations. An IDS may also be linked to video capabilities to activate a video feed when it is tripped. An array of beams, lasers, sensors, and alarms can be installed in any part of the tunnel environment. Application of this measure requires that the tunnel owner or operator perform a thorough assessment of the IDS needs and choose from the best affordable technology. The IDS may Countermeasure Description Use of photo or other identification to prove employees or vendors have permission to be on tunnel property. Types/Components Photo databases; proximity cards. Use All employees, contractors, and vendors. Category Minimum measures. Strengths Reasonable cost to provide a first, visible measure to discern trespassers. Weaknesses Terms and restrictions may be subject to contract or collective bargaining agreements. System can be defeated by forgery, or lack of database maintenance Rough Cost of Implementation Low—less than $1 million. Operation and Maintenance Measure is not mechanical, but database tracking of screened personnel must be kept current. Training Requirements Low—no special training required for tunnel employees. Life Expectancy Lifetime. Comments Table 52. Countermeasure 11: Employee identification system.

129 be layered to cover essential control centers; mechanical and electrical equipment rooms; and vulnerable areas inside, above, and around the tunnel. This evaluation may require external expertise. See Table 53. The amount of IDS equipment selected by the tunnel owner or operator will determine the total cost. Most IDSs require only standard maintenance and little more than a low-voltage power source. IDS provides a strong link in the security posture against both the intentional threat, such as someone intent on caus- ing disruption to the tunnel, and the unintentional hazard, such as a homeless person entering a mechanical room on a cold night. Countermeasure 13: Evacuation Protocols All tunnel systems may have, as a minimum, evacuation protocols designed to aid tunnel users in self-rescue and evac- uation from an incident area before the arrival of emergency response personnel. Evacuation protocols typically consist of working plans and signage to direct tunnel users to pathways, dedicated stairwells, cross-passageways and, occasionally, shel- ter areas that are safe from smoke and fire. The relatively sim- ple task of planning an evacuation is an effective, cost-efficient, and easy way to help an impacted tunnel user evacuate. See Table 54. An effective evacuation protocol needs to be kept fresh and active through constant oversight, exercise, and updating. Many evacuation plans are distributed to the public and tun- nel users in the form of leaflets or flyers. Countermeasure 14: Extend/Heighten Supply Air Intakes Newly constructed air intakes are accessible by height, by protective structures, or both. However, some existing air intakes must be retrofitted to remove the possibility of harm- ful substances or agents being introduced into the system. See Table 55. There are various types of tunnel ventilation air intake struc- tures. Road tunnels served by full transverse or semi-transverse supply systems typically house the fans and associated Countermeasure Description The installation of devices designed to provide notice when a person or item enters a specific area. Types/Components Beam; laser; sensor; alarm. Use Some or all tunnel access points. Category Minimum measures. Strengths Unstaffed, cost-effective means to monitor a large area with the least resources. Weaknesses Relies upon efficient maintenance to remain operational. Rough Cost of Implementation Medium—between $1 million and $3 million per tunnel. Cost depends on size of protected property. Operation and Maintenance High—system requires maintenance. Training Requirements None. Life Expectancy 5–10 years. Comments Countermeasure Description Establishment of evacuation protocols that are well-known, exercised, and supported. Types/Components Plans; signage; public instruction; drills and exercises. Use In all areas of the tunnel. Category Minimum measures. Strengths Provides a means for tunnel users and employees to self-rescue. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Low—signage and instruction need only to be updated. Training Requirements None. Life Expectancy 20–25 years. Comments Table 53. Countermeasure 12: Intrusion detection system. Table 54. Countermeasure 13: Evacuation protocols.

130 equipment in large ventilation structures. The supply airflow travels through intake louvers into the supply air plenum and through dampers, fans, sound attenuators, and ductwork before entering the tunnel. This path typically dictates that the intake louvers be located on an upper floor of the building, even though this upper floor is relatively inaccessible to the public. Transit systems, on the other hand, commonly have side- walk gratings that serve to bring outside air into the system. These gratings can lead to tunnels or stations and can be used in natural (piston-action) or mechanical ventilation systems. In any case, these air intakes must be protected from tamper- ing and harm. Retrofit designs include the construction of a vent shaft of sufficient height around the existing grating, the erection of fencing or some other permeable barrier at a suf- ficient distance from the existing grating, or the relocation of the grating via interior ductwork and/or structural elements. Countermeasure 15: Anti-Virus Software All tunnel system data networks must have programs to detect and eliminate computer-generated viruses. On a daily basis, hundreds of viruses, weak or virulent, will attempt to enter the data system, normally through an external data con- nection. These attempts, largely indiscriminate, must be thwarted at the point of entry (the external data connection). Intentional introduction of viruses from inside the network must also be prevented through a series of anti-virus meas- ures to protect the data network from itself. See Table 56. The installation of anti-virus software is a common prac- tice for anyone who has a computer or uses a data network. The software is readily available and relatively inexpensive. The effectiveness of this countermeasure is very high if the software is backed by a program of updates and mainte- nance. Such a program is readily available from commercial Countermeasure Description Design and construct durable air intake structures of increased height to thwart intentional or unintentional interference with the airflow. Types/Components Shafts; fences; screens; ductwork. Use All air intake devices. Category Minimum measures. Strengths This measure is a one-time investment to protect the air intake structures. Weaknesses New design may eventually be overcome by circumstance or intentional act of disruption. Rough Cost of Implementation Medium—between $1 million and $3 million per tunnel. Cost depends on local conditions. Operation and Maintenance Medium. Training Requirements None. Life Expectancy 20–40 years. Comments Countermeasure Description Install software designed to thwart the introduction of malicious software code into the data network of the tunnel owner or operator. Types/Components Software code. Use Entire data network. Category Minimum measures. Strengths This measure is an investment to protect the integrity of the data network. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Low. Training Requirements None. Life Expectancy Virus code definitions need to be continually updated. Comments This countermeasure is readily available from vendors who can provide a reliable, continually updated product to the tunnel owner or operator. Table 55. Countermeasure 14: Extend/heighten supply air intakes. Table 56. Countermeasure 15: Anti-virus software.

131 vendors and typically included in the price of the software purchase. Countermeasure 16: Computer Firewalls A complementary layer of cyber security for the tunnel data network includes the installation of firewalls. Firewalls are cyber codes written to prevent unauthorized entry to parts of the data network. These virtual partitions will authenticate the privilege rights of people attempting to enter areas of the network and deny access to those who do not appear on a specified list. See Table 57. Firewall software is frequently tied to anti-virus protec- tion by commercial vendors. The cost is relatively low for the protection provided. The challenge to the tunnel owner or operator is to establish the policies and regulations that will determine where the firewalls should exist. The tunnel owner or operator needs to establish permission levels for employees and visitors and then match those levels to the order of information contained within the whole of the network. Countermeasure 17: Backup Manual Control of Systems The design of new tunnels and the retrofit of older systems should include options for manual operation of MEC sys- tems, including those used for safety and security.Ventilation, lighting, pumps, and alarms should be capable of manual operation if their connections to the control center are breached. See Table 58. This redundancy exists in many older facilities, where the equipment was originally designed and installed to be operated manually. Later, retrofit controls may have been added to allow remote monitoring and operation. These retrofits should not have interfered with the ability of staff to manually throw a lever or a switch. Power sources to operate the systems should also be redundant. This may be accomplished through a dual feed or battery backup. The design of some newer tunnel systems may have elimi- nated manual control of MEC systems, relying instead on the technology available to allow remote or automated control. If this is the case, efforts should be made to restore local, man- ual control of these support systems to provide the tunnel owner or operator with important redundancy. This advance planning will ensure safe and continuous operation if the data connection is disabled or destroyed. Countermeasure 18: Regularly Scheduled Data Backup All data networks should be duplicated regularly to pro- tect against loss of information. These backups should be done to a server in a remote location from the main data processing center. The different locations lessen the risk that both primary and secondary data collection centers will be disabled by a localized event. Commercial services provide remote location data backups at a reasonable cost. See Table 59. The owner or operator will need to determine the when and how often data should be backed up, as well as which pieces of information should be copied. The remote backups may be done on any schedule, but should be no less often than once per day. The selected data may include financial, opera- tional, and/or transaction information. Countermeasure Description Install software designed to partition the data files of the tunnel owner or operator and allow only authorized access to the file compartments. Types/Components Software code. Use Across entire data network. Category Minimum measures. Strengths This measure is an investment to protect the integrity of the data network and halt unauthorized access. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Low. Training Requirements None. Life Expectancy Firewall settings and protection codes require regular maintenance and update. Comments This countermeasure is readily available from vendors who can provide a reliable, continually updated product to the tunnel owner or operator. Table 57. Countermeasure 16: Computer firewalls.

132 Countermeasure 19: Full-Scale Emergency Response Exercises At a minimum, every tunnel owner or operator should have a set of emergency response procedures and an emergency response plan (ERP) to address all potential emergencies at the facility. This plan should be based on recommendations and standards developed by organizations such as the NFPA and the World Road Association (PIARC). On a biannual or annual basis, full-scale emergency response exercises should be conducted at the tunnel to practice the procedures set forth in the ERP. These exercises should include tunnel operators; tunnel users (actual or staff); and all possible emergency response personnel, including firefighters, paramedics, and police. The simulated emergencies should vary from exercise to exercise, and participants should be unaware of the sched- ule to measure true preparedness. See Table 60. 5.4.2 Recommended Measures for an Elevated Threat Level Countermeasure 20: Guards at Portals A common practice among tunnel owners and operators during periods of elevated threat is to place fixed security posts at the tunnel portals to monitor people and traffic, to conduct inspections, and to be onsite to lead a response in the event of an incident that disrupts the normal mission of the tunnel. This measure is effective and adds a layer of deterrence to any person contemplating an intentional disruption, a layer of Countermeasure Description Design of switches, levers, and other manual devices to allow onsite control of support systems if the communication link to the operations center is breached. These manual control facilities should be at the site of support systems or near to the site of support systems. Types/Components Switches; levers; buttons. Use Critical support systems. Category Minimum measures. Strengths This measure provides a redundancy to the operation of the support systems. The manual controls enable the operation of the systems despite loss of central control and/or power. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance High—the systems machinery must always be kept in ready condition. Training Requirements High—tunnel staff need to be trained to operate the systems manually. Life Expectancy 20–40 years. Comments Countermeasure Description Program to duplicate data from network and then store that copy offsite. The offsite location should be at a distance from the main tunnel network system and have an independent power supply. Types/Components Software code. Use Across entire data network. Category Minimum measures. Strengths This measure is an investment to protect the integrity of the data network and mitigate any catastrophic loss due to hazard or threat. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Low. Training Requirements None. Life Expectancy The data backups should be done on frequent intervals. Comments This countermeasure is readily available from vendors who can provide a reliable, continually updated service to the tunnel owner or operator. Table 58. Countermeasure 17: Backup manual control of systems. Table 59. Countermeasure 18: Regularly scheduled data backup.

133 detection of threats, a layer of interdiction to parry a threat in the process of being delivered to the tunnel, and a layer of onsite mitigation to any successfully delivered threat. This measure, similar to that of roving patrols, is very flexible and rapidly deployable under any condition. The cost of the meas- ure is commensurate with the length of time the post is fixed at the portal. If the post is not fixed at the portal under normal operating conditions, then additional personnel and resources must be obtained to staff the countermeasure. See Table 61. Countermeasure 21: Inspections (Personal/Vehicle) Inspections of both vehicles (including cargo) and persons are efficient measures of tracking who and what is entering the tunnel and to interdict potential hazards and threats. Establishment of the inspection cordon may deter people from perpetrating an intentional disruption and provide a means of detecting intentional or unintentional hazards and threats. Inspections provide a layer of screening, thereby decreasing the chance of a hazard or threat being successfully delivered. This countermeasure typically inspires public con- fidence in the overall security posture of the tunnel and lim- its the decrease in tunnel use. See Table 62. The specific vehicles or vessels to be searched will be deter- mined by the owner or operator in conjunction with law enforcement and will be based on their combined intelli- gence. In each jurisdiction, law enforcement will be the authority vested with the power to conduct the inspections. Vessels may appear on suspicion lists because of ownership, cargo, origin, or destination. Vessels with a measure of risk Countermeasure Description Program to conduct regularly scheduled, full-scale emergency response exercises. Types/Components Module-based; initial training; refresher sessions. Use Required practice for all tunnel employees and emergency responders. Category Minimum measures. Strengths Low-cost, effective method of teaching tunnel employees and emergency responders how to handle various tunnel emergencies. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance None—measure is not mechanical. Training Requirements High—initial and refresher training of all employees is necessary. Life Expectancy 2–5 years to properly train newly hired employees. Comments Table 60. Countermeasure 19: Full-scale emergency response exercises. Countermeasure Description Placement of trained police or security guards in fixed posts at the portals of tunnel structures to inspect machinery and items entering the tunnel and to observe all activities occurring in and around the portal. Types/Components Police; private security. Use Fixed posts must be placed at each portal. Category Measures for an elevated threat level. Strengths Provides a thorough screening of all persons and material entering the tunnel through the portals. The use of trained police or security allows flexibility and rapidity of deployment. Weaknesses Potentially expensive. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance None—measure is not mechanical. Training Requirements High—each police officer or security guard placed at the portal needs to be highly trained to spot potential threats and to respond to confirmed threats. Life Expectancy Short-term duration, equal to elevated threat condition. Comments Table 61. Countermeasure 20: Guards at portals.

134 toward the tunnel may be excluded from passing near or over the subaqueous structure. Implementation of this inspection measure may require the installation of specialized machinery and/or the addition of personnel who are trained and legally authorized to con- duct inspections. There is a cost associated with these deployments, some of which may be offset by the use of existing, in-house resources. Total outlays must include staffing costs, thereby having a variable cost element. The tunnel may also lose users to other transportation assets if the suitability of a replacement is deemed viable to the delays associated with the inspections being conducted at the por- tals. The longer the inspection measure is deployed, the higher the cost will be to the owner or operator. The eco- nomic cost to the public may also increase as the shipment of goods becomes delayed. The inspection measure is most effective when coupled with a viable method to determine which persons or vehi- cles to inspect. An unfounded, blanket inspection ritual may not be as effective as a measured one based on sound assumptions. To achieve the proper mix, tunnel owners/ operators are encouraged to tailor their inspection methodol- ogy and surrounding protocols to local applicable conditions. Countermeasure 22: Bomb-Sniffing Dogs Another common, existing practice among tunnel own- ers and operators is to conduct sweeps of the tunnel areas in search of explosives. A persistent program of frequent visits will decrease the opportunity for an aggressor to leave explosives within or near the tunnel. Deployment of bomb- sniffing dogs can be expanded to tunnel portals, support facilities (such as electrical substations), and nearby docks and marine facilities. The origin of an explosive threat will be outside the tunnel, allowing a sufficient window of opportunity for detection. The K-9 approach may also serve as an effective deterrent. Because of the success rate of dogs detecting even the faintest traces of explosives, an aggressor could anticipate that his or her attempt to move or plant an explosive would fail with this countermeasure in place. See Table 63. A trained K-9 is very effective at detecting explosives and can be deployed and moved rapidly to a specific location. The K-9 program requires ongoing costs and maintenance to keep and train the dogs. A dog can typically only work for 3 to 5 hours a day and has a service life of only 4 to 5 years. There- fore, there is a continual need to resupply K-9 units to main- tain effectiveness. Countermeasure 23: Onsite Credential Checks During periods of elevated threat, a heightened security posture may include implementation of a credentials check on jobsites. The check would focus particularly on areas of active construction or rehabilitation. A guard or similarly recognized individual would inspect the credentials of each person entering the site. The credentials would likely include a photo identification issued by the tunnel owner or operator that is valid for certain periods of time. See Table 64. Countermeasure 24: Waterborne Patrols When a tunnel crosses below a navigable waterway, water- borne patrols may be instituted in response to an elevated Countermeasure Description The implementation of a system to inspect all persons and vehicles (including cargo) entering a tunnel structure. Types/Components Vehicle; ship; persons; cargo; automated inspection; hand inspection. Use Inspection system must be applied at all entry points to ensure equal application. Category Measures for an elevated threat level. Strengths Properly applied, inspection system should ensure that hazardous items are kept out of the tunnel. Weaknesses Greatly increases costs to shippers that use the tunnel system, and decreases the flow of traffic through the tunnel. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Use of automated inspection device, such as a scanner, will require external vendors and maintenance. Training Requirements High—each screener placed at the portal needs to be highly trained to spot potential hazards and threats and to respond to confirmed hazards and threats. Life Expectancy Short-term duration. Comments Table 62. Countermeasure 21: Inspections (personal/vehicle).

135 threat condition. Waterborne patrols over the footprint of the tunnel elevate the security posture of the tunnel by providing a flexible deterrence, detection, and interdiction force at a major access point to the tunnel structure. Waterborne patrols can be tasked to conduct inspections of vessels cross- ing the footprint or to halt traffic into the same area. They can be deployed based on timeframes of expected vessel traffic or can maintain a fixed post. The use of waterborne patrols in the area over the tunnel footprint is effective in securing that area. See Table 65. The cost of this measure includes the capital investment of a boat and the variable costs associated with operating and maintaining the boat as well as a trained crew. Maintenance costs will depend on the amount of time for which the boat is used. The sum of the costs depends on how often this meas- ure is deployed in response to an elevated threat level. Countermeasure 25: Ship-Tracking Protocols A longer, strategic measure conducted in advance of, in place of, or in conjunction with waterborne patrols may be the institution of ship-tracking protocols in navigable waterways above a tunnel footprint. These protocols will allow the tunnel owner or operator to have input into the restrictions placed on vessels transiting the area. Content, speed, and time of crossing may be regulated. These regula- tions would require the tunnel owner or operator to work with the U.S. Coast Guard, which maintains jurisdiction over navigable waterways. The effectiveness of the protocols depends on the enforcement. Widespread adherence to the protocols may allow easier detection and, therefore, interdic- tion of a noncomplying transiting vessel. See Table 66. Implementation of this countermeasure would require substantial resources and time to gain the voluntary acquies- cence of local shippers and users of the waterway. Cost vari- ables would also include software and tracking devices. Countermeasure 26: Explosive Detectors—Mobile Mechanical devices with the intent of detecting explosives within the tunnel environment may be deployed in a mobile, tactical manner for use at several locations. See Table 67. Mobile detectors have many of the same capabilities and limitations as fixed detectors. Their chief advantage is the Countermeasure Description Using mobile canines to detect explosives in the tunnel. Types/Components Police; security. Use Throughout tunnel system. Category Measures for an elevated threat level. Strengths Very flexible in deployment schemes. K-9 is very effective in detecting explosives. Weaknesses Limited by availability of trained dogs. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance None—measure is not mechanical. Training Requirements High—each K-9 handler and dog requires specialized, in-depth training. Life Expectancy 2–5 years. Comments Countermeasure Description Credential checks on each jobsite entrance. Types/Components Employees; contractors; photo identification. Use At the entrance to all jobsites. Category Measures for an elevated threat level. Strengths Ensures that unauthorized individuals are not permitted onto a site. Weaknesses None. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance Low—no mechanization. Training Requirements Medium—guard or checker must be trained to recognize a valid credential and to interdict a false identification. Life Expectancy 1 year. Comments Table 63. Countermeasure 22: Bomb-sniffing dogs. Table 64. Countermeasure 23: Onsite credential checks.

136 ability to be deployed at different locations based on chang- ing threat levels. However, these detectors require increased maintenance. Countermeasure 27: C/B/R Detectors—Mobile C/B/R detectors provide a means to detect C/B/R materi- als before they enter the tunnel environment. The C/B/R detectors can be located on mobile units for easy deployment. The C/B/R detectors may use the current technologies avail- able and may contain sensors to detect individual materials. See Table 68. The C/B/R measure requires a capital investment, special- ized handling of the machinery, and training for those oper- ating the systems. 5.4.3 Recommended Permanent Enhancements Countermeasure 28: Explosive Detectors—Fixed Mechanical devices with the intent of detecting explosives within the tunnel environment may be fixed and installed at tunnel perimeters and entrances. See Table 69. Countermeasure Description Deploy mobile, boat-based patrols to monitor boat traffic over an underwater tunnel crossing. Types/Components Mobile boat based. Use Use for water crossings only. Category Measures for an elevated threat level. Strengths Provides an active presence to the waters above a tunnel. Particularly useful in protecting tunnels under navigable waterways. Weaknesses May not be able to stop a suicide attacker intent on scuttling the boat. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance High—boats require specialized maintenance. Training Requirements High—personnel on patrol boats require specialized training to operate boat, board, or other vessels and to conduct interdiction activities. These personnel are likely drawn from law enforcement and must be authorized to conduct waterborne searches. Life Expectancy Short-term duration to match escalated threat level. Comments Countermeasure Description Establishment of restrictions for any vessel transiting the waterway above a tunnel footprint. This action may require the coordination of nearby docks and water users. Types/Components Water areas above tunnel footprint. Use Use for water crossings only. Category Measures for an elevated threat level. Strengths Provides a standard-use pattern for vessels to transit the area above the tunnel. The restrictions should prevent vessels from stopping or staging above the tunnel. Weaknesses May hamper shipping patterns in area. Also, spotlights vulnerable location. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance High—boats require specialized maintenance. Training Requirements Medium—a high level of coordination must occur. Life Expectancy Continual use of restrictions. Comments Table 65. Countermeasure 24: Waterborne patrols. Table 66. Countermeasure 25: Ship-tracking protocols.

137 Countermeasure Description Implementation of fixed or mobile explosive detection devices in and around the tunnel area. Types/Components Fixed and mounted inside tunnel structure or mobile and moved by mechanical means. Use At tunnel portals or inside traffic areas. Category Measures for an elevated threat level. Strengths Provides a measure of detection to find explosives in the tunnel. Weaknesses Detection devices may be impaired by the harsh environment of most tunnels. The systems may be impacted by dirt, grime, and poor air quality. Rough Cost of Implementation Low—less than $1 million per mobile unit. Medium—between $1 and $3 million per fixed unit. Operation and Maintenance High—units require specialized maintenance. Training Requirements Medium—supplemental training is required. Life Expectancy 5–10 years. Comments New technology with increasing reliability is continually being researched and designed. Improvements to reliability and durability are in the future. The fixed explosive detector typically consists of a mechanical device that extracts air samples and, using a variety of means, tests them for explosive residue. Some models are capable of performing the test immediately, and others rely on a technician removing the sample and con- ducting the detection test in another location. The fixed detector relies on the extraction of air samples that are clean enough to be tested. Impurities that may contaminate the air sample must be low to allow a true measure of explosive residue to be detected. Foul air or clogged intake lines can alter the integrity of the explosive detection test. Fixed detectors are designed to mechanically emulate the chemi- cal sensing abilities of a dog. Explosive detectors are not guaranteed to prevent the entry of explosives, and this tech- nology is continually being reworked. Countermeasure 29: C/B/R Detectors—Fixed C/B/R detectors provide a means to detect C/B/R materi- als before they enter the tunnel environment. The C/B/R detectors can be permanently installed. The C/B/R detectors may use the current technologies available and may contain sensors to detect individual materials. See Table 70. The C/B/R measure requires a capital investment, special- ized handling of the machinery, and training for those oper- ating the systems. Countermeasure 30: Redundant Ventilation Systems To ensure an adequate supply of fresh air to the tunnel and the exhaust of contaminated, foul, or smoke-filled air Countermeasure Description Install sensors at tunnel portals to provide notification of C/B/R material entering the tunnel. The detectors provide a means to detect and interdict the material. Types/Components Chemical; biological; radiological. Use Located at portals. Category Measures for an elevated threat level. Strengths Provides a measure of detection and interdiction of C/B/R material. Weaknesses Current technology is imperfect. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance High—machinery and detectors require specialized maintenance and handling. Training Requirements Medium—technicians or personnel operating the detectors require specialized training. Life Expectancy 5–10 years. Comments Table 67. Countermeasure 26: Explosive detectors—mobile. Table 68. Countermeasure 27: C/B/R detectors—mobile.

138 during an incident, the tunnel owner or operator may wish to install a redundant ventilation system. The system may be designed and built to supply air to and/or exhaust air from specific critical areas, evacuation shelters, and path- ways or to ventilate air throughout the entire tunnel struc- ture. The redundant system may be designed to operate independently of the main ventilation system, with a dif- ferent power source and air source. Both systems will be controlled from a control station located outside the tun- nel. The system may provide pressurized stairwells and evacuation zones dictated by local code or installed as part of original design for newer assets. Existing structures or systems may sometimes be used to reduce the cost of instal- lation. See Table 71. A redundant ventilation system requires a significant capital investment by the tunnel owner or operator. The effectiveness of the redundant system relies on a commitment to maintain- ing the system and testing its functionality at regular intervals. Countermeasure 31: Interior Liner Steel Plates or Panels The thickness of the steel plates or energy-absorbing steel panels will depend on the specific tunnel construction type, the construction materials (concrete, brick, etc.), the sur- rounding soil or earth geology, the groundwater conditions, the size of the IED or fire being considered, and the proxim- ity of the hazard or threat to the liner. See Figure 15. Countermeasure Description Implementation of fixed or mobile explosive detection devices in and around the tunnel area. Types/Components Fixed and mounted inside tunnel structure or mobile and moved by mechanical means. Use At tunnel portals or inside traffic areas. Category Measures for an elevated threat level. Strengths Provides a measure of detection to find explosives in the tunnel. Weaknesses Detection devices may be impaired by the harsh environment of most tunnels. The systems may be impacted by dirt, grime, and poor air quality. Rough Cost of Implementation Low—less than $1 million per mobile unit. Medium—between $1 million and $3 million per fixed unit. Operation and Maintenance High—units require specialized maintenance. Training Requirements Medium—supplemental training is required. Life Expectancy 5–10 years. Comments New technology with increasing reliability is continually being researched and designed. Improvements to reliability and durability are in the future. Countermeasure Description Install sensors at tunnel portals to provide notification of C/B/R material entering the tunnel. The detectors provide a means to detect and interdict the material. Types/Components Chemical; biological; radiological. Use Located at portals. Category Permanent enhancements. Strengths Provide a measure of detection and interdiction of C/B/R material. Weaknesses Current technology is imperfect. Rough Cost of Implementation Low—less than $1 million per tunnel. Operation and Maintenance High—machinery and detectors require specialized maintenance and handling. Training Requirements Medium—technicians or personnel operating the detectors require specialized training. Life Expectancy 5–10 years. Comments Table 70. Countermeasure 29: C/B/R detectors—fixed. Table 69. Countermeasure 28: Explosive detectors—fixed.

139 Constructability issues include the following: • Interior clearances for installation of steel plates or energy- absorbing panels. • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment and material). • Contractor staging area outside of tunnel. • Work trains for rail tunnels; portable platforms for high- way tunnels. • Protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 32: Interior Liner Concrete Panels The thickness of the precast or cast-in-place concrete pan- els will depend on the specific tunnel construction type, the construction materials (concrete, brick, etc.), the surround- ing earth geology, the groundwater conditions, the size of the IED or fire being considered, and the proximity of the hazard or threat to the liner. See Figure 16. Constructability issues include the following: • Interior clearances for installation of concrete panels. • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment, and material). • Contractor staging area outside of tunnel. Countermeasure Description Establishment of redundant ventilation to be used to supply fresh air and remove impure air in an emergency condition if the main ventilation system is not available. Types/Components Supply fans (blowers); exhaust fans; ducts; dampers; louvers; power source; backup power source. Use Installation to provide redundancy to critical tunnel areas, including evacuation routes. Strengths Provides redundancy to airflow systems. Weaknesses Requires high level of maintenance. Rough Cost of Implementation High—over $10 million per tunnel. Cost depends on tunnel length, ventilation system type, and scope of redundant system. Operation and Maintenance High—system must be kept in constant state of readiness. Training Requirements None. Life Expectancy 20–25 years. Comments Table 71. Countermeasure 30: Redundant ventilation systems. Figure 15. Interior liner steel plates or panels. Figure 16. Interior liner concrete panels.

140 • Work trains for rail tunnels; portable platforms for high- way tunnels. • Protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 33: Interior Concrete or Chemical Grouting To provide more strength for existing tunnels within the zone influenced by the hazard or threat of explosion or fire, and to overcome problems associated with these hazards and threats, a variety of protective systems can be applied. These protective systems include ground treatment measures such as cement-rich concrete and chemical grouting, which enable the tunnel liners to withstand higher forces. However, grouting mechanisms are difficult to verify and site-specific geotechni- cal information varies from project to project. See Figure 17. Constructability issues include the following: • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment, and material). • Contractor staging area outside of tunnel. • Work trains for rail tunnels; portable platforms for high- way tunnels. • Protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 34: Interior Liner Bolting or Tie-Backs Another method of strengthening the tunnel liner is to use bolting or tie-backs with wire mesh and to apply shotcrete over it. The suitability of this method depends greatly on the surrounding geology. For example, this method is very effec- tive for strong to medium rock types, but not for medium to weak rock types. See Figure 18. Constructability issues include the following: • Interior clearances for installation of bolting or tie-backs, wire mesh, and shotcrete. • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment, and material). • Contractor staging area outside of tunnel. • Work trains for rail tunnels; portable platforms for high- way tunnels. • Protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 35: Exterior (Ground) Concrete or Chemical Grouting Grouting mechanisms are difficult to verify, and site- specific geotechnical information varies from project to Figure 17. Interior concrete or chemical grouting.

141 project. To provide more strength for existing tunnels within the zone influenced by the hazard or threat of explo- sion or fire, and to overcome problems associated with these hazards and threats, a variety of protective systems can be applied. These protective systems include ground treatment measures (such as cement-rich concrete and chemical grouting), which enable the tunnel liners to withstand higher forces. See Figure 19. Constructability issues include the following: • All work is conducted outside of the tunnel. • The interior of the tunnel must be monitored by employ- ees or expert contractors to ensure that the grouting process is not negatively impacting the tunnel. • Depending on the land use above, – Permits may be required from the agency owning the land of the grout injection sites, – Coordination with other agencies may be required, – Utility relocation and coordination may be required, and/or – Work hours may depend solely on the contractor’s schedule. Countermeasure 36: Rip-Rap over Tunnel Rip-rap can consist of stones, blocks of concrete, or other similar material. It is laid on the bottom of a water body, such as a river bed or stream, to protect the tunnel below from threats such as large IEDs or explosive containers dropped from a passing ship. See Figure 20. Constructability issues include the following: • Material is delivered via barge and lowered by cranes. • Environmental issues require permits and approval from responsible agencies. • Coordination with water traffic authorities is required. • All work is conducted outside of the tunnel. Countermeasure 37: Precast Concrete Slab over Tunnel Similar to rip-rap, the precast concrete slab is laid on the bottom of a water body, such as a river bed or stream, to pro- tect the tunnel below from threats such as large IEDs or explosive containers dropped from a passing ship. The thickness of the slab should depend on the size of the IED being considered and the amount of cover over the tunnel. However, the ground geology and the structural capacity of the tunnel may limit the amount of weight that can be added and, thus, must be taken into consideration. See Figure 21. Constructability issues include the following: • Material is delivered via barge and lowered by cranes. The size of the concrete segments depends on the capacity of the crane. • Environmental issues require permits and approval from responsible agencies. • Coordination with water traffic authorities is required. • All work is conducted outside of the tunnel. Figure 18. Interior liner bolting or tie-backs.

142 Countermeasure 38: Interior Roof Steel Plates Interior roof steel plates are appropriate only for flat- topped, cut-and-cover tunnels. The thickness of the steel plates will depend on the available clearances, the tunnel con- struction materials (concrete or brick), the depth of cover over the tunnel, the surrounding soil or earth geology, the groundwater conditions, the size of the IED or fire being con- sidered, and the proximity of the hazard or threat to the liner. See Figure 22. Constructability issues include the following: • Interior clearances for installation of steel plates. • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment, and material). • Contractor staging area outside of tunnel. • Work trains for rail tunnels; portable platforms for high- way tunnels. • Protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 39: Interior Roof Concrete Panels Interior roof concrete panels are appropriate only for flat- topped, cut-and-cover tunnels. The thickness of the concrete panels will depend on the available clearances, the tunnel construction materials (concrete or brick), the depth of cover Figure 19. Exterior (ground) concrete or chemical grouting.

143 over the tunnel, the surrounding soil or earth geology, the groundwater conditions, the size of the IED or fire being con- sidered, and the proximity of the hazard or threat to the liner. See Figure 23. Constructability issues include the following: • Interior clearances for installation of concrete panels. • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment, and material). • Contractor staging area outside of tunnel. • Work trains for rail tunnels; portable platforms for high- way tunnels. • Protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 40: Exterior Roof Steel Plates Exterior roof steel plates are appropriate only for flat- topped, cut-and-cover tunnels. The thickness of the steel plates will depend on the tunnel construction materials (concrete or brick), the depth of cover over the tunnel, the surrounding soil or earth geology, the groundwater conditions, the size of the IED or fire being considered, and the proximity of the hazard or threat to the liner. See Figure 24. Figure 20. Rip-rap over tunnel.

144 Constructability issues include the following: • All work is conducted outside of the tunnel. • Depending on the land use above, – Permits may be required, – Coordination with other agencies may be required, – Utility relocation and coordination may be required, and/or – Work hours may depend solely on the contractor’s schedule. Countermeasure 41: Exterior Roof Concrete Panels The thickness of the concrete panels will depend on the size of the IED being considered and the amount of cover over the tunnel. However, the ground geology and the structural capacity of the tunnel may limit the amount of weight that can be added and, thus, must be taken into consideration. See Figure 25. Constructability issues include the following: • All work is conducted outside of the tunnel. • Depending on the land use above, – Permits may be required, – Coordination with other agencies may be required, – Utility relocation and coordination may be required, and/or – Work hours may depend solely on the contractor’s schedule. Figure 21. Precast concrete slab over tunnel.

145 Countermeasure 42: Bollards to Control Access Bollards are typically constructed around the outside perimeter or across the front entrances of stations or buildings in order to protect the buildings and occupants from vehicles, including those that may be carrying IEDs. The bollards are designed to withstand the force of a speeding van or truck. Depending on the application, bollards can be permanent or removable. See Figure 26. Constructability issues include the following: • There must be sufficient property (width and depth) to accommodate the bollards. • Depending on who owns the property, – Permits may be required, – Coordination with other agencies may be required, – Utility relocation and coordination may be required, and/or – Work hours may depend solely on the contractor’s schedule. Figure 22. Interior roof steel plates. Figure 23. Interior roof concrete panels.

146 Figure 24. Exterior roof steel plates. Figure 25. Exterior roof concrete panels. Figure 26. Bollards to control access.

147 to the columns. The concrete increases the fire resistance of the column. If additional fire resistance is desired, the concrete can be mixed with polypropylene fibers. See Figure 28. Constructability issues include the following: • Interior clearances for installation of concrete encasement. • Coordination of passengers or other users if area is occupied. Countermeasure 45: RFP Wrapping of Columns Reinforced fiber protection (RFP) systems are used for blast hardening and mitigation for circular reinforced con- crete columns that support stations and air-rights structures. The RFP wrapping provides strength and ductility to mini- mize damage; prevent collapse; and enhance blast perform- ance of columns, beams, walls, and ceiling slabs. If fire Figure 28. Concrete encasement of columns. Countermeasure 43: Fencing to Control Access Fencing is built around the perimeter of a building or facil- ity to keep intruders from entering. There are many different types of fencing. See Figure 27. Constructability issues include the following: • There must be sufficient property to accommodate the fencing. • Depending on who owns the property, – Permits may be required, – Coordination with other agencies may be required, – Utility relocation and coordination may be required, and/or – Work hours may depend solely on the contractor’s schedule. Countermeasure 44: Concrete Encasement of Columns Existing support columns can be strengthened by adding concrete encasements around the steel. This measure can be done for all columns or selected columns. The thickness of the encasement will depend on the size of the IED or fire being considered and the relative proximity of the hazard or threat Figure 27. Fencing to control access.

148 Constructability issues include the following: • The facility must have sufficient space to accommodate the additional columns and/or walls. • Applicable fire and life-safety (i.e., egress) codes must be considered if new walls are constructed. • Coordination of passengers or other users if area is occupied. Countermeasure 48: Floodgates Flooding in a tunnel can be extremely dangerous and damaging. This is particularly true if an underwater tunnel is interconnected with other tunnels and/or passenger stations because the water has the potential to travel farther, cause more destruction, and interrupt tunnel operations. To lessen the potential for extensive flooding from situa- tions such as these, floodgates are sometimes installed. See Figure 32. Constructability issues include the following: • Significant vertical clearances for installation of floodgates. • Extensive tunnel utility relocation. • Work hours (weekdays, nighttime, and weekends); required track outages or highway lane closures. • Limited number of crews per shift due to space constraints. • Access to tunnel (personnel, equipment, and material). • Contractor staging area outside of tunnel. • Work trains or portable platforms; protection services for contractors (i.e., flagging); safety training for employees. Countermeasure 49: Barrier Walls Barrier walls are sometimes constructed on the water side of a tunnel portal to create a stand-off distance and protect the portal from waterborne hazards and threats, such as off- course ships or ships carrying explosives. See Figure 33. Constructability issues include the following: • Environmental issues require permits and approval from responsible agencies. • Coordination with water traffic authorities. Figure 29. RFP wrapping of columns. Figure 30. Steel jacketing of columns. Figure 31. Redundant columns or walls. resistance is an issue, there are composite systems on the mar- ket that allow the addition of a spray-applied coating on top of the RFP system to increase the fire rating. See Figure 29. Constructability issues include the following: • Minor interior clearances for installation of RFP wrapping. • Coordination of passengers or other users if area is occupied. Countermeasure 46: Steel Jacketing of Columns Steel jackets can be installed around existing support columns. The steel jacket can be designed based on the size of the IED or fire being considered and on the relative proxim- ity of the hazard or threat to the columns. See Figure 30. Constructability issues include the following: • Minor interior clearances for installation of steel jackets. • Coordination of passengers or other users if area is occupied. Countermeasure 47: Redundant Columns or Walls In some cases, such as a particularly vulnerable air-rights structure or transit station, it may be deemed necessary to build additional support columns or walls. This measure would, of course, increase the support capacity in the event of an explosive or large fire. To justify this level of effort, the haz- ard or threat scenarios should be examined closely to deter- mine the size of the IED or fire to be considered as well as the proximity of the hazard or threat to the existing and new columns and walls. See Figure 31.

149 • Contractor staging area is outside of tunnel. • Underwater construction expertise required. 5.5 Conclusion When using these guidelines, one must recognize that most mitigation countermeasures fall between two extremes. One extreme is to prevent all damage at enormous cost,and the other extreme is to spend nothing and risk enormous damage. Tun- nel owners, operators, and engineers must make balanced deci- sions in selecting countermeasures for their facilities, preferably to risk an acceptable level of damage at a reasonable cost. How- ever,finding this balance becomes more complicated when con- sidering possible loss of human life, which is extremely difficult • Contractor staging area outside of tunnel. • Underwater construction expertise required. Countermeasure 50: Bollards or Fenders in the Water Bollards or fenders can be constructed on the water side of a tunnel portal to create a stand-off distance and protect the portal from waterborne hazards and threats, such as off- course ships or ships carrying explosives. See Figure 34. Constructability issues include the following: • Environmental issues require permits and approval from responsible agencies. • Coordination with water traffic authorities. A. Original tunnel cross section. C. Tunnel plan view with floodgates. D. Tunnel cross section with floodgates. B. Tunnel elevation with floodgates. Figure 32. Floodgates

150 Figure 34. Bollards or fenders in the water. Figure 33. Barrier walls.

subjective. They depend on a number of variables, including tunnel length, tunnel construction type, construction materi- als, surrounding earth geology and groundwater conditions, available clearances, and interruption of operations. To fur- ther explore the suitability of particular countermeasures to a specific facility, in-house or outside experts should be used to develop conceptual designs and cost estimates. Once these designs and estimates meet approval, final construction doc- uments—including design drawings, specifications, construc- tion cost estimates, and schedules—should be developed. 151 if not impossible to assign a value to. Protection of human life should always receive the highest priority. While preparing budgets for tunnel-hardening counter- measures, be careful to include the costs associated with labor, material, equipment, protective services (i.e. flagging), outage costs of highways or rail lines, and interruption of traffic and operations during construction. Although the relative effec- tiveness and order-of-magnitude cost ratings in the counter- measure guides are based on many years of engineering expertise and past project experience, the rating systems are

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TRB’s National Cooperative Highway Research Program (NCHRP) Report 525: Surface Transportation Security and TRB’s Transit Cooperative Research Program (TCRP) Report 86: Public Transportation Security series publications have jointly published Making Transportation in Tunnels Safe and Secure. The report is Volume 12 in each series. The report is designed to provide transportation tunnel owners and operators with guidelines for protecting their tunnels by minimizing the damage potential from extreme events such that, if damaged, they may be returned to full functionality in relatively short periods. The report examines safety and security guidelines for owners and operators of transportation tunnels to use in identifying principal vulnerabilities of tunnels to various hazards and threats. The report also explores potential physical countermeasures; potential operational countermeasures; and deployable, integrated systems for emergency-related command, control, communications, and information.

NCHRP Report 525: Surface Transportation Security is a series in which relevant information is assembled into single, concise volumes—each pertaining to a specific security problem and closely related issues. The volumes focus on the concerns that transportation agencies are addressing when developing programs in response to the terrorist attacks of September 11, 2001, and the anthrax attacks that followed. Future volumes of the report will be issued as they are completed.

The TCRP Report 86: Public Transportation Security series assembles relevant information into single, concise volumes, each pertaining to a specific security problem and closely related issues. These volumes focus on the concerns that transit agencies are addressing when developing programs in response to the terrorist attacks of September 11, 2001, and the anthrax attacks that followed. Future volumes of the report will be issued as they are completed.

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