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Assessing Interactions Between Access Management Treatments and Multimodal Users (2018)

Chapter: Appendix C: Assessment of Data and Information Needs

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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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Suggested Citation:"Appendix C: Assessment of Data and Information Needs." National Academies of Sciences, Engineering, and Medicine. 2018. Assessing Interactions Between Access Management Treatments and Multimodal Users. Washington, DC: The National Academies Press. doi: 10.17226/25344.
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114 A P P E N D I X C : A S S E S S M E N T O F D A T A A N D I N F O R M A T I O N N E E D S Assessment of Data and Information Needs Introduction This appendix describes the process used to identify access management (AM) techniques that should be studied in Phase 2 of the project. This process is based on consideration of (1) the extent to which information about the safety or operational effect of a technique is needed by practitioners and (2) the resources required to develop relationships that quantify this effect. The focus of the assessment was on the information practitioners need when evaluating the effect of alternative techniques on the safety and operational characteristics of pedestrians, bicycles, buses, or trucks. The identification of techniques is partly based on the findings from the review of the literature and the findings from an agency survey, as documented in Chapter 2. The identification is also partly based on the findings from an assessment of the “utility” and development cost of new performance relationships, as described in this appendix. In this regard, utility describes the value a performance relationship indirectly provides to the traveling public by more reliably informing decision-makers during the project development process. The technique assessment process consists of three stages that were completed in sequence. During each stage, the number of candidate AM techniques were winnowed down to a smaller number of high- priority techniques for which information is most needed and can be cost-effectively obtained. This appendix consists of five sections. The first section describes the process used in Stage 1 to assess the utility and cost of developing performance relationships for alternative AM techniques. The second section describes the process used in Stage 2 to outline the study design for (and refine the estimated cost of) developing performance relationships for the viable techniques. The third section describes the process used in Stage 3 to select the few techniques recommended for study in Phase 2. The fourth section describes the findings from a reassessment of several techniques (conducted at the request of the project panel). The fifth section presents the final set of techniques to be studied in Phase 2. Stage 1 – Initial Selection of Techniques The Stage 1 activities initially focused on developing the following items: (1) a definition of “utility,” (2) a procedure for quantifying the utility of the performance relationships associated with each AM technique, and (3) a procedure for estimating the approximate cost of developing the performance relationships associated with each technique. Then, the subset of techniques was selected that yielded the highest total utility (if the corresponding performance relationships were developed). Finally, the researchers reviewed the selected techniques and used their judgment to refine the results. The details of these activities are summarized in the next several subsections. A total of 74 techniques were identified during the literature review process (as described in Appendix A). Most of the techniques are expected to have some effect on the safety or operation of the four travel modes (i.e., pedestrians, bicycles, buses, or trucks) of interest to the project. Table 70 shows all 592 possible performance relationships (= 74 techniques × 2 performance categories × 4 travel modes), where one table cell represents one performance relationship. The cells in columns 2 through 9 of this table

115 indicate which of the relationships are documented in the literature (i.e., “Yes” if quantitative, “Trend” if qualitative), which ones are undocumented but may be developed through research (i.e., “Possible”), and which ones are undocumented and unlikely to exist (i.e., “No”). About 550 of the 592 relationships shown in Table 70 are identified as “undocumented but may be developed through research” and, as such, are candidates for development in Project 03-120. Table 70. Technique influence on operations and safety. Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty Primary Techniques Identified in NCHRP Report 420 1a. Establish traffic signal spacing criteria Yes Yes Trend Pos- sible Trend Trend Pos- sible Pos- sible Corridor Simula- tion Crash Reports 1b. Establish spacing for unsignalized access Trend Yes Trend Pos- sible Yes Trend Pos- sible Pos- sible Corridor Simula- tion Simula- tion 1c. Establish corner clearance criteria No No Pos- sible Pos- sible No No Pos- sible Pos- sible Site Simula- tion Crash Reports 1d. Establish access separation distances at interchanges Trend Trend Trend Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Crash Reports 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median Yes Trend Yes Pos- sible Yes Yes Pos- sible Pos- sible Corridor Simula- tion Crash Reports 2c. Close existing median openings Trend Trend Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Simula- tion Crash Reports 2d. Replace full median opening with median designed for left turns from the major roadway Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion 3a. Install left-turn deceleration lanes where none exists Trend Trend Trend Yes Pos- sible Pos- sible Pos- sible Yes Site Simula- tion Simula- tion 3b. Install left-turn acceleration lane at unsignalized intersection Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field 3c. Install continuous two-way left-turn lane on undivided highway Yes Pos- sible Yes Pos- sible Yes Pos- sible Pos- sible Pos- sible Corridor Simula- tion Crash Reports 3d. Install U-turns as an alternative to direct left turns Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Pos- sible Pos- sible Corridor Simula- tion Simula- tion 3e. Install jug handle and eliminate left turns along highways Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion 4a. Install right-turn deceleration lane or right-turn lane Yes Trend Trend Trend Yes Yes Pos- sible Trend Site Simula- tion Simula- tion 4b. Install continuous right-turn lane Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Crash Reports 5a. Consolidate driveways Yes Trend No Pos- sible Trend Trend No Pos- sible Corridor Simula- tion Simula- tion 5b. Channelize driveways to discourage or prohibit left turns on undivided highways Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Simula- tion

116 Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty 5c. Install barrier to prevent uncontrolled access along property frontage Yes Trend Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor or Site Field Crash Reports 5d. Coordinate driveways on opposite sides of street Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field 6a. Install frontage road to provide access to individual parcels Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Simula- tion Crash Reports 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Crash Reports Selected Other Techniques Identified in NCHRP Report 420 B-1 Interchanges B-1-1 Build interchange (at major intersection or activity center). Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Crash Reports B-1-2 Modify freeway ramps to improve access. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-1-3 Build freeway frontage road. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Simula- tion Crash Reports B-2 Frontage Roads B-2-2 Construct a bypass road. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible System or Corridor Simula- tion Crash Reports B-2-3 Build a reverse frontage road (i.e., Backage Road). Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Simula- tion Crash Reports B-3 Medians - Left Turns B-3-1 Install median barrier with no direct left-turn ingress or egress. Yes Pos- sible Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Site Simula- tion Simula- tion B-3-7 Install channelizing islands to prevent left-turn deceleration lane vehicles from returning to through lanes. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-3-8 Install median channelization to control the merge of left-turn egress vehicles. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-3-12 Install alternating left-turn lane. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Field Crash Reports B-3-13 Install isolated median and deceleration lane to shadow and store left-turning vehicles. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-3-14 Install left-turn deceleration lane in lieu of right-angle crossover. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-3-15 Install median storage for left- turn egress vehicles. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-3-16 Increase storage capacity of existing left-turn deceleration lane. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-3-17 Channelize left-turn lanes across wide medians. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field

117 Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty B-3-20 Construct flyover to accommodate left-turn egress/and ingress movements. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-3-21 Prohibit left turns. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor or Site Field Reports or sim. B-3-22 Build left-turn connecting roads. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor or Site Simula- tion Crash Reports B-4 Right Turns B-4-5 Install channelizing islands to move ingress merge point laterally away from the highway. Yes Yes Pos- sible Trend Yes Yes Pos- sible Trend Site Simula- tion Simula- tion B-4-6 Move sidewalk–driveway crossing laterally away from highway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-5 Access/Driveway Location – Retrofit Consolidation B-5-1-2 Consolidate existing access whenever separate parcels are assembled under one purpose, plan, entity, or usage. Pos- sible Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-5-2-1 Encourage connections between adjacent properties (even when each has highway access). Trend Trend Trend Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Not amen- able to analysis -- -- B-5-2-2 Require access on collector street (when available) in lieu of additional driveway on highway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-5-2-3 Relocate or reorient access. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion Relocation B-5-3-2 Locate a new driveway opposite an intersection or driveway and install a traffic signal where warranted and properly spaced. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-5-3-3 Install two one-way driveways in lieu of one two-way driveway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-5-3-4 Install two two-way driveways with limited turns in lieu of one standard two-way driveway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-5-3-5 Install two one-way driveways in lieu of two two-way driveways. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-5-3-6 Install two two-way driveways with limited turns in lieu of two standard two-way driveways. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-6 Traffic Controls B-6-1 Install traffic signal at high-volume driveways. Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Crash Reports B-6-2 Install traffic signals to manage traffic flow and meter traffic for larger gaps. Trend Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Crash Reports

118 Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty B-6-3 Restrict parking on the roadway next to driveways to increase driveway turning speeds. Trend Pos- sible No No Trend Pos- sible No No Corridor or Site Simula- tion Crash Reports B-6-4 Provide reversible operation of access drive. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-6-5 Implement curbside loading controls. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Field Crash Reports B-6-6 Prohibit left-turn driveway maneuvers on an undivided highway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Field Crash Reports B-6-7 Install one-way operations on the highway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible System or Corridor Simula- tion Crash Reports B-6-8 Rep lace parallel on-street parking with off-street parking. Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor Simula- tion Crash Reports B-6-10 Install roundabout2 Yes Yes Yes Pos- sible Trend Pos- sible Pos- sible Pos- sible Site Simula- tion Simula- tion B-7 Access/Driveway Design Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 Trend Trend Trend Trend Trend Trend Pos- sible Pos- sible Site Simula- tion Simula- tion B-7-1 Widen right through lane to limit right-turn encroachment onto the adjacent lane to the left. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-7-6 Install driveway channelizing island to prevent left-turn driveway encroachments conflicts. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-7-7 Install driveway channelizing island to prevent right-turn deceleration lane vehicles from returning to the through lanes. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-7-8 Install driveway channelizing island to control the merge area of right- turn egress vehicles. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-7-9 Regulate the maximum width of driveways, B-7-23 widen driveways to improve storage Trend Pos- sible No Pos- sible Pos- sible Pos- sible No Pos- sible Not amen- able to analysis -- -- B-7-10 Install visual cues of the driveway. Trend Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Not amen- able to analysis -- -- B-7-11 Improve driveway sight distance and B-7-12 Regulate minimum sight distance Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-7-13 Optimize sight distance in the permit authorization stage. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Not amen- able to analysis -- --

119 Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty B-7-14 Increase the effective approach width of the driveway (horizontal geometrics). Trend Trend Trend Trend No No Pos- sible Pos- sible Site Field Field B-7-15 Improve the vertical geometrics of the driveway. Trend Trend Trend Trend No No Pos- sible Pos- sible Site Field Field B-7-16 Increase the turning speed of right-angle median crossovers by increasing the effective approach width. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site Field Field B-7-17 Install additional exit lane on driveway. Pos- sible Pos- sible No Pos- sible Pos- sible Pos- sible No Pos- sible Site Simula- tion Simula- tion B-7-18 Require two-way driveway operation where internal circulation is not available. Pos- sible Pos- sible No Pos- sible Pos- sible Pos- sible No Pos- sible Site Field Field B-7-19 Control driveway design elements. Trend Trend Trend Trend Pos- sible Pos- sible Pos- sible Pos- sible Not amen- able to analysis -- -- B-7-21 Provide full driveway access with steady flow in one direction of travel on arterial road. Pos- sible Pos- sible No Pos- sible Pos- sible Pos- sible No Pos- sible Not amen- able to analysis -- -- B-7-22 Design driveways so signals impact only one side of artery at any one location. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Not amen- able to analysis -- -- Notes: 1 -Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 - Technique added or modified by the NCHRP 03-120 research team. 3 – Treatment effect indicators: “Yes” documented quantitative effect; “Trend” documented qualitative effect (but no documented quantitative effect); “Possible” no study found but possible effect; and “No” effect is unlikely or negligible. Two application scales are identified in Table 70, they include: corridor scale and site scale. Techniques are considered to be corridor applications if they specify a change in the design or operation of a major arterial roadway and this change extends for a significant length of the facility (e.g., access spacing, median type). In contrast, some changes are intended to improve access at a specific location on the roadway (e.g., an intersection or driveway), or along a short length of roadway (e.g., a street segment). These techniques are generally tactical in nature and are considered to be site-specific applications. Thus, a “site” is defined to be an intersection, driveway, or street segment. In general, the effect of a technique on safety or operation can be most accurately quantified by matching the study area with the application scale. In this regard, the evaluation of a technique with corridor scale would likely require the collection of corridor-level data (i.e., data describing the entire corridor). There are several alternative sources of data that can be used to quantify most performance relationships. The sources considered for this project included field measurements, simulation, and crash records. The choice of data source was influenced by the technique being studied, the performance measure category (i.e., operations or safety) of interest, and the cost of data collection.

120 The information in the last three columns of Table 70 is discussed in a subsequent section. The terms data source and application scale are described more fully in Chapter 3. Summary of Technique Categories As described in Appendix B, the agency survey included several questions that asked the respondents about 16 technique categories. The questions inquired about the respondent’s use of the techniques; the technique’s impact on the performance of the pedestrian, bicycle, bus, and truck travel modes; and the respondent’s need for more information about these impacts. Six of the 16 technique categories correspond directly to one of the 74 techniques identified in Table 30 (e.g., Manage spacing of traffic signals). Other categories were associated with two or more techniques (e.g., Manage the location and spacing of unsignalized access includes five different techniques). Fifteen of the 16 technique categories in the survey collectively represent 33 of the 74 techniques. The sixteenth category in the survey (i.e., “Other”) generally represents the remaining 41 techniques. The 16 categories are identified in Table 71. Table 71. Technique categories addressed in survey. Technique Category Technique 1. Install non-traversable medians a. Install non-traversable median on undivided highway; and replace two- way left-turn lane with non-traversable median; b. Install isolated median barriers (with no direct left-turn ingress or egress). 2. Manage the location, spacing and design of median openings a. Close existing median openings; b. Replace full median opening with median designed for left turns from the major roadway; c. Install U-turns as an alternative to direct left turns. 3. Manage spacing of traffic signals a. Establish traffic signal spacing criteria 4. Manage the location and spacing of unsignalized access a. Establish spacing for unsignalized access (e.g., driveways); b. Establish corner clearance criteria; c. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection; d. Require access on collector street (when available) in lieu of direct on highway; e. Relocate or reorient access as part of roadway reconstruction. 5. Consolidate driveways a. Consolidate existing access whenever separate parcels are assembled under one purpose, plan, entity, or usage; b. Consolidate driveways during roadway projects. 6. Manage the spacing of signalized and unsignalized access on crossroads in the vicinity of freeway interchanges a. Establish access separation distances at interchanges 7. Install continuous two-way left-turn lane on undivided highway (non-road diet scenarios) a. Install continuous two-way left-turn lane on undivided highway 8. Install left-turn lanes a. Install left-turn deceleration lanes at roadway intersections; b. Install left-turn deceleration lanes at median openings; c. Increase storage capacity of existing left-turn deceleration lane. d. Install alternating left-turn lane. 9. Install right-turn lanes a. Install right-turn deceleration lane at roadway intersections; b. Install right-turn deceleration lane at site driveways

121 Technique Category Technique 10. Control driveway design elements a. Require design of driveways with the appropriate return radii, throat width, channelization, number of lanes and throat length for the type of traffic to be served; b. Channelize driveways to discourage or prohibit left turns on undivided highways and to guide ingress/egress movements; c. Improve the vertical geometrics of the driveway; d. Install barrier to prevent uncontrolled access along property frontage; e. Install visual cues of the driveway. 11. Provide adequate sight distance at access points a. Improve driveway sight distance and regulate minimum sight distance 12. Manage the location and placement of parking a. Replace curb parking with off-street parking; b. Restrict parking on the roadway in the vicinity of driveways to improve sight distance. 13. Install roundabout a. Install roundabout at roadway intersection; and install roundabout at interchange. 14. Install service or frontage roads a. Install frontage road to provide access to individual parcels; b. Install rear service road to provide access to individual parcels. 15. Improve supporting network a. Connect existing street networks to relieve primary roadway; and encourage connections between adjacent properties. 16. Other techniques (not listed above) (not applicable) Definition of Technique Utility In general, the term utility is used to describe the value a performance relationship indirectly provides to the traveling public by more reliably informing decision-makers during the project development process. Following this general concept, the utility of a performance relationship was based on the following components:  Frequency that the associated technique is implemented by a public agency.  Likelihood that the technique will have an impact (positive or negative) on the safety or operation of a pedestrian, bicycle, bus, or truck.  Practitioner need for a performance relationship to assist with the evaluation of alternative AM techniques. Utility Assessment Procedure The utility assessment procedure consisted of the use of survey results to develop a score for each of the three components of utility (as listed in the previous subsection). The utility was then based on the average of the three scores. The score for each of the three components of utility is represented as a ranking from 1 to 16 (based on the use of 16 technique categories). A rank value was used to make the score for each component comparable. This need was introduced because (1) a count (i.e., the number of respondents) was used to quantify the “frequency of implementation,” (2) a percentage was used to quantify the “likelihood of impact,” and (3) a count (based on 178 respondents) was used to quantify “practitioner need.” Other methods for combining these three scores were considered but they were found to be unnecessarily complicated or to bias the computed utility such that it unfairly favored one of the three components more than the other components.

122 Frequency of Implementation The agency survey included a question that asked the respondents to indicate which of the 16 technique categories are being used in their jurisdiction. The respondents provided a “Yes/No” indication for each category. The “frequency of implementation” score was based on the count of respondents that indicated “Yes” to the question (i.e., they are using the technique). Specifically, the survey count for each of the 16 technique categories was converted to a rank (from 1 to 16), with 1 being assigned to the technique category receiving the highest count. For example, the category Manage the location, spacing and design of median openings had the highest count of respondents, so it was assigned a rank of 1. Likelihood of Impact on Safety or Operation The survey included a series of questions that inquired about known positive and negative impacts of a technique category on the safety or operation of the pedestrian, bicycle, bus, or truck travel modes. A set of four questions individually addressed the direction of impact (i.e., positive, negative) and the performance measure category (i.e., safety, operations). The respondents provided a “Yes/No” indication for each of the four travel modes, for each of the 16 technique categories (i.e., each of the four questions had 64 responses = 4 × 16). The number of respondents to each of the four questions varied from 139 to 144. To make the responses comparable among the four questions, they were converted into the percentage of respondents indicating “Yes.” For a given travel mode, there were four questions (i.e., positive impact on safety, positive impact on operations, negative impact on safety, negative impact on operations), with each question having one percentage value for each of the 16 technique categories. This percentage indicated the percentage of respondents indicating “Yes” to the question for the associated technique category. For a given travel mode and technique category, the percentages associated with the two mutually exclusive questions about safety (i.e., positive impact on safety, and negative impact on safety) were added. This sum represented the percentage of respondents that believed the technique category had an impact on the safety of the associated travel mode (the impact could be positive or negative). Similarly, the percentages associated with the two mutually exclusive questions about operations (i.e., positive impact on operations, and negative impact on operations) were added. As a result, for a given travel mode, the survey results were reduced from four questions to two questions (i.e., some impact on safety, some impact on operations), with each question having one percentage value for each of the 16 technique categories. For a given travel mode and technique category, the percentages associated with the aforementioned two questions were further combined to represent an estimate of the percentage of respondents that believe there is a safety impact, operational impact, or both. This percentage was computed using the following equation (percentages are entered as real numbers in the range of 0.0% to 100.0%): Equation 1 , 100 1 1 0.01 , , 1 0.01 , , where Pm,c = estimated percentage of respondents that believe technique category c has a safety impact, operations impact, or both on travel mode m (m = pedestrian, bike, bus, truck); Psafety,m,c = percentage of respondents that believe technique category c has a safety impact on travel mode m; and Poperations,m,c = percentage of respondents that believe technique category c has an operations impact on travel mode m.

123 Using this equation, the survey results were reduced to one equivalent response (i.e., some impact on safety, operations, or both) for each travel mode. In other words, for each travel mode, this technique produced one percentage value for each of the 16 technique categories. As a final step, the results from Equation 1 were combined into one response (per technique category) that reflected all four travel modes. Specifically, for a given technique category, the four percentages from Equation 1 were further combined to represent an estimate of the percentage of respondents that believe there is a safety impact, operational impact, or both on one or more modes. This percentage was computed using the following equation: Equation 2 100 1 1 0.01 , 1 0.01 , 1 0.01 , 1 0.01 , where Pc = estimated percentage of respondents that believe technique category c has a safety impact, operations impact, or both on one or more travel modes. Using this equation, the survey results were reduced to one equivalent response (i.e., some impact on the safety, operations, or both of one or more modes). In other words, this technique produced one percentage value for each of the 16 technique categories. The percentage computed using Equation 2 was converted into a rank (from 1 to 16), with 1 being assigned to the technique category receiving the highest percentage. For example, the category Install non-traversable medians had the highest percentage (i.e., 99 percent) so it was assigned a rank of 1. Information Need The survey included a question that asked the respondents to indicate their analysis needs and priorities for each of the technique categories. The question was focused on categories for which more information was needed about the associated techniques’ effect on the safety or operation of the pedestrian, bicycle, bus, or truck travel mode. The respondents were asked to identify the three categories for which more information was most needed. The “information need” score was based on the count of respondents that identified a category as one for which they needed more information. Specifically, the survey count for each of the 16 technique categories was converted to a rank (from 1 to 16), with 1 being assigned to the technique category receiving the highest count. For example, the category Manage spacing of traffic signals had the highest count (i.e., 44 based on 178 respondents) so it was assigned a rank of 1. Technique Category Utility The utility of each technique category was computed by first taking an average of the score (i.e., rank) for each of three components of utility. This average score was then subtracted from 17 (= total number of categories + 1) to produce a utility value that ranged from 1 to 16, with 16 used to indicate the category with the largest utility (i.e., most used, most likely to impact a non-auto mode, and for which information is most needed). The utility value was computed using the following equation. Equation 3 17 , , ,3 where Uc = utility for technique category c; Suse,c = score for frequency of implementation for technique category c; Simpact,c = score for likelihood of impact for technique category c; and

124 Sneed,c = score for information need for technique category c. Technique Utility The survey questions focused on technique categories (as opposed to individual techniques) to ensure the respondents could complete the survey in a reasonable amount of time. In this manner, the utility of each category was computed rather than that of the individual techniques that comprise the category. It was determined that the most reasonable approach for determining a technique’s utility was to assign the computed utility for a technique category to each technique in that category. For example, the category “consolidate driveways” was found to have a utility of 8.7. This category consists of two techniques (i.e., consolidate driveways during roadway projects; and consolidate existing access whenever separate parcels are assembled under one purpose, plan, entity, or usage), so each technique was assigned a utility of 8.7. Through this process, a utility value was assigned to each of the 74 techniques. In general, this approach provided satisfactory estimates of technique utility. However, in a few instances, this approach was believed to overstate or understate the utility of a given technique. This outcome occurred when (1) a category included multiple techniques and (2) the utility was believed to vary widely among the techniques (i.e., one or two techniques had a low utility and one or two techniques had a high utility). The researchers decided that this issue could be addressed as a final activity in Stage 1 wherein they reviewed the list of techniques with the highest utility, and then used their judgment to refine the list. Expected Technique Utility The utility score is intended to be an indication of the value that a newly developed performance relationship may indirectly provide to the traveling public by more reliably informing decision-makers during the project development process. However, this value would not likely be realized if the research undertaken to develop the new relationship was unsuccessful. Thus, research undertaken to develop each technique is associated with a “probability of success.” This probability was judged by the researchers based on their consideration of (1) the likely difficulty of acquiring data in the time needed, (2) anticipated difficulty in finding sufficient numbers of sites to ensure statistical validity of the findings, and (3) amenability of the technique to study. The “probability of success” was used to compute an expected utility for each technique. Specifically, the expected utility was computed by multiplying the utility value for each technique by the probability of success. This formulation is based on the assumption that the utility of the research results are “0.0” if the research is likely to be unsuccessful. The expected utility is computed using the following equation. Equation 4 , where EUt = expected utility for technique t; Ut = utility for technique t; and ps,t = probability of success of new research conducted for technique t. The computed utility, probability of success, and expected utility for each technique is listed in columns 2, 3, and 4, respectively, of Table 72. The data in the remaining columns are described in a subsequent section.

125 Table 72. Estimated utility and development cost by technique for Stage 1. Technique (listed by ID code1) All Techniques Selected Techniques U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity Performance C os t o f S tu dy Te ch ni qu es Se le ct ed To ta l U til ity To ta l C os t O pe ra tio n Sa fe ty Total: 335.7 $6,143,750 15 193.3 $1,206,250 Primary Techniques Identified in NCHRP Report 420 1a. Establish traffic signal spacing criteria 12.0 1.0 12.0 2 4 $105,000 1 12.0 $105,000 1b. Establish spacing for unsignalized access 13.7 1.0 13.7 4 4 $130,000 1 13.7 $130,000 1c. Establish corner clearance criteria 13.7 1.0 13.7 4 4 $55,000 1 13.7 $55,000 1d. Establish access separation distances at interchanges 5.0 1.0 5.0 4 4 $65,000 0 0.0 $0 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non- traversable median 14.0 1.0 14.0 2 3 $85,000 1 14.0 $85,000 2c. Close existing median openings 14.0 1.0 14.0 4 4 $130,000 1 14.0 $130,000 2d. Replace full median opening with median designed for left turns from the major roadway 14.0 1.0 14.0 4 4 $55,000 1 14.0 $55,000 3a. Install left-turn deceleration lanes where none exists 8.7 1.0 8.7 3 3 $41,250 0 0.0 $0 3b. Install left-turn acceleration lane at unsignalized intersection 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 3c. Install continuous two-way left-turn lane on undivided highway 5.3 1.0 5.3 3 4 $117,500 0 0.0 $0 3d. Install U-turns as an alternative to direct left turns 14.0 1.0 14.0 4 4 $130,000 1 14.0 $130,000 3e. Install jug handle and eliminate left turns along highways 1.0 1.0 1.0 4 4 $55,000 0 0.0 $0 4a. Install right-turn deceleration lane or right-turn lane 9.3 1.0 9.3 2 2 $27,500 1 9.3 $27,500 4b. Install continuous right-turn lane 9.3 1.0 9.3 4 4 $65,000 1 9.3 $65,000 5a. Consolidate driveways 8.7 1.0 8.7 2 3 $85,000 0 0.0 $0 5b. Channelize driveways to discourage or prohibit left turns on undivided highways 7.0 1.0 7.0 4 4 $150,000 0 0.0 $0 5c. Install barrier to prevent uncontrolled access along property frontage 7.0 1.0 7.0 3 4 $132,500 0 0.0 $0 5d. Coordinate driveways on opposite sides of street 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 6a. Install frontage road to provide access to individual parcels 2.3 1.0 2.3 4 4 $130,000 0 0.0 $0 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection 13.7 1.0 13.7 4 4 $55,000 1 13.7 $55,000 Selected Other Techniques Identified in NCHRP Report 420 B-1 Interchanges B-1-1 Build interchange (at major intersection or activity center). 1.0 1.0 1.0 4 4 $65,000 0 0.0 $0 B-1-2 Modify freeway ramps to improve access. 1.0 1.0 1.0 4 4 $55,000 0 0.0 $0 B-1-3 Build freeway frontage road. 1.0 1.0 1.0 4 4 $130,000 0 0.0 $0 B-2 Frontage Roads

126 Technique (listed by ID code1) All Techniques Selected Techniques U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity Performance C os t o f S tu dy Te ch ni qu es Se le ct ed To ta l U til ity To ta l C os t O pe ra tio n Sa fe ty B-2-2 Construct a bypass road. 1.0 1.0 1.0 4 4 $130,000 0 0.0 $0 B-2-3 Build a reverse frontage road (i.e., Backage Road). 2.3 1.0 2.3 4 4 $130,000 0 0.0 $0 B-3 Medians - Left Turns B-3-1 Install median barrier with no direct left-turn ingress or egress. 14.0 1.0 14.0 4 4 $130,000 1 14.0 $130,000 B-3-7 Install channelizing islands to prevent left-turn deceleration lane vehicles from returning to through lanes. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-3-8 Install median channelization to control the merge of left-turn egress vehicles. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-3-12 Install alternating left-turn lane. 8.7 1.0 8.7 4 4 $150,000 0 0.0 $0 B-3-13 Install isolated median and deceleration lane to shadow and store left-turning vehicles. 8.7 1.0 8.7 4 4 $55,000 0 0.0 $0 B-3-14 Install left-turn deceleration lane in lieu of right-angle crossover. 1.0 1.0 1.0 4 4 $55,000 0 0.0 $0 B-3-15 Install median storage for left-turn egress vehicles. 1.0 1.0 1.0 4 4 $55,000 0 0.0 $0 B-3-16 Increase storage capacity of existing left-turn deceleration lane. 8.7 1.0 8.7 4 4 $55,000 0 0.0 $0 B-3-17 Channelize left-turn lanes across wide medians. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-3-20 Construct flyover to accommodate left-turn egress/and ingress movements. 1.0 1.0 1.0 4 4 $55,000 0 0.0 $0 B-3-21 Prohibit left turns. 1.0 1.0 1.0 4 4 $150,000 0 0.0 $0 B-3-22 Build left-turn connecting roads. 1.0 1.0 1.0 4 4 $130,000 0 0.0 $0 B-4 Right Turns B-4-5 Install channelizing islands to move ingress merge point laterally away from the highway. 1.0 1.0 1.0 2 2 $27,500 0 0.0 $0 B-4-6 Move sidewalk–driveway crossing laterally away from highway. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-5 Access/Driveway Location – Retrofit Consolidation B-5-1-2 Consolidate existing access whenever separate parcels are assembled under one purpose, plan, entity, or usage. 8.7 1.0 8.7 3 4 $48,750 0 0.0 $0 B-5-2-1 Encourage connections between adjacent properties (even when each has highway access). 4.7 0.0 0.0 4 4 $130,000 0 0.0 $0 B-5-2-2 Require access on collector street (when available) in lieu of additional driveway on highway. 13.7 1.0 13.7 4 4 $55,000 1 13.7 $55,000 B-5-2-3 Relocate or reorient access. 13.7 1.0 13.7 4 4 $55,000 1 13.7 $55,000 Relocation B-5-3-2 Locate a new driveway opposite an intersection or driveway and install a traffic signal where warranted and properly spaced. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-5-3-3 Install two one-way driveways in lieu of one two-way driveway. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0

127 Technique (listed by ID code1) All Techniques Selected Techniques U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity Performance C os t o f S tu dy Te ch ni qu es Se le ct ed To ta l U til ity To ta l C os t O pe ra tio n Sa fe ty B-5-3-4 Install two two-way driveways with limited turns in lieu of one standard two-way driveway. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-5-3-5 Install two one-way driveways in lieu of two two-way driveways. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-5-3-6 Install two two-way driveways with limited turns in lieu of two standard two-way driveways. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-6 Traffic Controls B-6-1 Install traffic signal at high-volume driveways. 1.0 1.0 1.0 1 4 $46,250 0 0.0 $0 B-6-2 Install traffic signals to manage traffic flow and meter traffic for larger gaps. 1.0 1.0 1.0 4 4 $65,000 0 0.0 $0 B-6-3 Restrict parking on the roadway next to driveways to increase driveway turning speeds. 7.7 1.0 7.7 2 2 $65,000 0 0.0 $0 B-6-4 Provide reversible operation of access drive. 1.0 1.0 1.0 4 4 $55,000 0 0.0 $0 B-6-5 Implement curbside loading controls. 1.0 1.0 1.0 4 4 $150,000 0 0.0 $0 B-6-6 Prohibit left-turn driveway maneuvers on an undivided highway. 1.0 1.0 1.0 4 4 $150,000 0 0.0 $0 B-6-7 Install one-way operations on the highway. 1.0 1.0 1.0 4 4 $130,000 0 0.0 $0 B-6-8 Rep lace parallel on-street parking with off- street parking. 7.7 1.0 7.7 2 4 $105,000 0 0.0 $0 B-6-10 Install roundabout2 13.7 1.0 13.7 3 4 $48,750 1 13.7 $48,750 B-7 Access/Driveway Design Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 7.0 0.0 0.0 4 4 $55,000 0 0.0 $0 B-7-1 Widen right through lane to limit right-turn encroachment onto the adjacent lane to the left. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-7-6 Install driveway channelizing island to prevent left-turn driveway encroachments conflicts. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-7-7 Install driveway channelizing island to prevent right-turn deceleration lane vehicles from returning to the through lanes. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-7-8 Install driveway channelizing island to control the merge area of right-turn egress vehicles. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-7-9 Regulate the maximum width of driveways, B- 7-23 widen driveways to improve storage 1.0 0.5 0.5 3 3 $48,750 0 0.0 $0 B-7-10 Install visual cues of the driveway. 7.0 0.0 0.0 4 4 $65,000 0 0.0 $0 B-7-11 Improve driveway sight distance and B-7-12 Regulate minimum sight distance 10.7 1.0 10.7 4 4 $80,000 1 10.7 $80,000 B-7-13 Optimize sight distance in the permit authorization stage. 1.0 0.0 0.0 4 4 $130,000 0 0.0 $0 B-7-14 Increase the effective approach width of the driveway (horizontal geometrics). 1.0 1.0 1.0 4 2 $57,500 0 0.0 $0 B-7-15 Improve the vertical geometrics of the driveway. 7.0 1.0 7.0 4 2 $57,500 0 0.0 $0 B-7-16 Increase the turning speed of right-angle median crossovers by increasing the effective approach width. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0

128 Technique (listed by ID code1) All Techniques Selected Techniques U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity Performance C os t o f S tu dy Te ch ni qu es Se le ct ed To ta l U til ity To ta l C os t O pe ra tio n Sa fe ty B-7-17 Install additional exit lane on driveway. 1.0 1.0 1.0 3 3 $41,250 0 0.0 $0 B-7-18 Require two-way driveway operation where internal circulation is not available. 1.0 0.5 0.5 3 3 $60,000 0 0.0 $0 B-7-19 Control driveway design elements. 1.0 1.0 1.0 4 4 $65,000 0 0.0 $0 B-7-21 Provide full driveway access with steady flow in one direction of travel on arterial road. 1.0 1.0 1.0 3 3 $48,750 0 0.0 $0 B-7-22 Design driveways so signals impact only one side of artery at any one location. 1.0 1.0 1.0 4 4 $65,000 0 0.0 $0 Notes: 1 -Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 - Technique added or modified by the NCHRP 03-120 research team. Cost Assessment Procedure The cost of developing the needed performance relationships for a given technique was estimated based on consideration of the technique analysis scale (i.e., corridor or site), proposed source of data, and number of unknown relationships for the technique. The analysis scale describes the size of the study area that would be needed to fully quantify the impact of a technique on modal safety or operations. This scale is often dictated by the technique’s application scale. Some techniques are applied to an intersection and others are applied along several miles of a street or highway. The application scale is identified for each technique in Table 70. The data source (i.e., simulation, field, or crash reports) is also identified in Table 70. The cost assessment procedure included some simplifying assumptions that provided sufficient accuracy to meet the objectives of Stage 1. One simplifying assumption was that a technique’s analysis scale is equivalent to its application scale. Another assumption, derived from past experience, is that the cost of developing relationships for a given technique using a corridor analysis scale is about twice the cost of developing relationships using a site analysis scale. These assumptions were believed to be adequate for Stage 1 purposes. The subset of 20 techniques advanced from Stage 1 was re-evaluated in Stage 2 on the basis of a more detailed assessment of development cost. For a given technique, the initial cost estimate of developing performance relationships at the “site” analysis scale is listed in Table 73. Each cost listed in the table represents the cost of developing the four performance relationships (one for each non-auto mode) for a given performance measure category. The costs are estimates based on the experience of the research team. Table 73. Performance relationship development costs for techniques applied at “site” scale. Performance Measure Category Data Source Cost to Develop Relationships, $/technique Operations Simulation 25,000 Field 35,000 Safety Simulation 30,000 Crash reports 40,000 Field 45,000

129 The availability of existing performance relationships in the literature was considered in the cost estimate. This availability was identified during the literature review (refer to columns 2 to 9 in Table 70. The costs listed in Table 73 were reduced (by ratio) when one or more of the relationships were known to be available in the literature. They were also reduced if it was determined that a relationship is not needed because the technique is unlikely to have an effect on the corresponding mode. The reduced cost represented the funds needed to develop undocumented relationships for those techniques that are likely to have an effect on one or more of the non-auto modes. The resulting computed development cost for each technique is listed in column 7 of Table 72. The following example is used to illustrate the cost assessment for Technique 1a - Establish traffic signal spacing criteria. Table 70 indicates that the data source for the operations-based performance measures is simulation. The cost to develop the four operations relationships at the site analysis scale is estimated as $25,000, as shown in the first row of Table 73. However, two of the four possible operations-based performance relationships are indicated in Table 70 to be available in the literature (i.e., one or more studies were identified that quantified the effect of the technique on the operation of the pedestrian and bicycle modes). Therefore, the development cost was reduced (by ratio) to $12,500 (= 2/4 × $25,000). For Technique 1a, Table 70 indicates that the data source for the safety-based performance measures is crash reports. Based on Table 73, the cost to develop the four safety relationships at the site level using crash reports is estimated as $40,000. None of the four possible safety-based performance relationships are indicated in Table 70 to be available in the literature. Therefore, all four relationships would be developed using the $40,000 budget. The application scale is indicated in Table 70 to be “corridor.” Therefore, the corridor analysis scale is used to define the study area. This relatively large study area is assumed to double the cost of the site- level study. Thus, the cost of developing performance relationships for this technique is estimated as $105,000 (= 2 × [12,500 + 40,000]). This cost assessment procedure was used in Stage 1 to (1) verify that the cost of studying any individual technique would not exceed the available budget and (2) to estimate the total cost of studying the techniques moved forward from Stage 1 to Stage 2. All individual study costs were determined to be within the available budget; therefore, it was not necessary in Stage 1 to eliminate any techniques on the basis of study cost. Selection Process An initial list of 15 techniques was identified to carry forward to Stage 2 solely on the basis of total expected utility. The identified techniques are ones that the practitioner survey indicates would be of greatest value to study, as these techniques are: (1) used frequently by public agencies, (2) believed by practitioners to impact one or more non-auto modes, and (3) believed by practitioners to require more information on their impacts to non-auto modes. Setting a cutoff of a total expected utility value of 9.3 produced a set of 15 techniques. These techniques are indicated by a “1” in column 8 of Table 72. They represent the following seven categories:  Installing non-traversable medians;  Managing the location, spacing, and design of median openings;  Managing the location and spacing of unsignalized accesses;  Installing roundabouts;  Managing the spacing of traffic signals;  Providing adequate sight distance at access points; and  Installing right-turn lanes.

130 The 15 techniques were supplemented by five additional techniques identified through the application of the research team’s professional judgment. These techniques came from categories which were assigned lower utilities on the basis of the practitioner survey results, but which nevertheless were judged to have potential merit to study. In particular, the 41 techniques assigned to the “other” category in the practitioner survey (which collectively had the lowest utility score) were reviewed to make sure that no promising technique was overlooked simply by having been assigned to this category. The five additional techniques selected by the research team are identified in the following list:  Consolidate driveways. The utility value for this technique was just below the cutoff, it is a commonly used AM technique, and it potentially provides benefits for all non-auto modes.  Channelize driveways to discourage or prohibit left turns. This is a commonly used AM technique whose impacts on non-auto modes are not well-understood.  Replace curb parking with off-street parking. Depending on how the freed-up space is used, this technique potentially provides benefits for all non-auto modes.  Install a continuous two-way left-turn lane on an undivided highway. This is a common road diet technique that is often used to provide space for bicycle lanes and space for median treatments to improve pedestrian crossings.  Move the sidewalk–driveway crossing laterally away from the roadway. This technique directly impacts the pedestrian mode. Selection Results The 20 techniques most needing research (to identify their performance relationships) are identified in Table 74. The estimated cost to study the 15 techniques with the highest total expected utility was approximately $1,206,250, while the five additional techniques identified by the research team added approximately another $537,500. The total development cost for all 20 techniques was estimated as $1,743,750. As this cost was more than five times the available budget, the Stage 2 evaluation procedure was used next to reduce the number of techniques to one that could be studied within the funds available to the project. Sample Calculation This section demonstrates the calculation of utility and cost associated with Technique 1a - Establish traffic signal spacing criteria. Calculation of Technique Utility In general, the term utility is used to describe the value a performance relationship indirectly provides to the traveling public by more reliably informing decision-makers during the project development process. Following this general concept, the utility of a performance relationship was based on the following components:  Frequency that the associated technique is implemented by a public agency.  Likelihood that the technique will have an impact (positive or negative) on the safety or operation of a pedestrian, bicycle, bus, or truck.  Practitioner need for a performance relationship to assist with the evaluation of alternative AM techniques.

131 Table 74. Top 20 AM Techniques selected in Stage 1. Technique (listed by ID code1) All Techniques U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity Available Relationships C os t o f S tu dy O pe ra tio n Sa fe ty Total: 233.0 $1,743,750 Primary Techniques Identified in NCHRP Report 420 1a. Establish traffic signal spacing criteria 12.0 1.0 12.0 2 4 $105,000 1b. Establish spacing for unsignalized access 13.7 1.0 13.7 4 4 $130,000 1c. Establish corner clearance criteria 13.7 1.0 13.7 4 4 $55,000 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median 14.0 1.0 14.0 2 3 $85,000 2c. Close existing median openings 14.0 1.0 14.0 4 4 $130,000 2d. Replace full median opening with median designed for left turns from the major roadway 14.0 1.0 14.0 4 4 $55,000 3c. Install continuous two-way left-turn lane on undivided highway 5.3 1.0 5.3 3 4 $117,500 3d. Install U-turns as an alternative to direct left turns 14.0 1.0 14.0 4 4 $130,000 4a. Install right-turn deceleration lane or right-turn lane 9.3 1.0 9.3 2 2 $27,500 4b. Install continuous right-turn lane 9.3 1.0 9.3 4 4 $65,000 5a. Consolidate driveways 8.7 1.0 8.7 2 3 $85,000 5b. Channelize driveways to discourage or prohibit left turns on undivided highways 7.0 1.0 7.0 4 4 $150,000 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection 13.7 1.0 13.7 4 4 $55,000 Selected Other Techniques Identified in NCHRP Report 420 B-3 Medians - Left Turns B-3-1 Install median barrier with no direct left-turn ingress or egress. 14.0 1.0 14.0 4 4 $130,000 B-4 Right Turns B-4-6 Move sidewalk–driveway crossing laterally away from highway. 1.0 1.0 1.0 4 4 $80,000 B-5 Access/Driveway Location – Retrofit Consolidation B-5-2-2 Require access on collector street (when available) in lieu of additional driveway on highway. 13.7 1.0 13.7 4 4 $55,000 B-5-2-3 Relocate or reorient access. 13.7 1.0 13.7 4 4 $55,000 B-6 Traffic Controls B-6-8 Rep lace parallel on-street parking with off-street parking. 7.7 1.0 7.7 2 4 $105,000 B-6-10 Install roundabout2 13.7 1.0 13.7 3 4 $48,750 B-7 Access/Driveway Design B-7-11 Improve driveway sight distance and B-7-12 Regulate minimum sight distance 10.7 1.0 10.7 4 4 $80,000 Notes: 1 -Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 - Technique added or modified by the NCHRP 03-120 research team.

132 Frequency of Implementation The agency survey included a question that asked the respondents to indicate which of the 16 technique categories are being used in their jurisdiction. The respondents provided a “Yes/No” indication for each category. The “frequency of implementation” score was based on the count of respondents that indicated “Yes” to the question (i.e., they are using the technique). Specifically, the survey count for each of the 16 technique categories was converted to a rank (from 1 to 16), with 1 being assigned to the technique category receiving the highest count. This question received 186 “Yes” responses for the technique category associated with Technique 1a (i.e., category 3). Relative to the other 15 technique categories (identified in Table 71), the 186 responses ranked eighth. Seven of the technique categories received more “Yes” responses, implying more frequent use of the techniques in categories 1 through 7. Likelihood of Impact on Safety or Operation The survey included a series of questions that inquired about known positive and negative impacts of a technique category on the safety or operation of the pedestrian, bicycle, bus, or truck travel modes. A set of four questions individually addressed the direction of impact (i.e., positive, negative) and the performance measure category (i.e., safety, operations). The respondents provided a “Yes/No” indication for each of the four travel modes, for each of the 16 technique categories (i.e., each of the four questions had 64 responses = 4 × 16). The number of respondents to each of the four questions varied from 139 to 144. To make the responses comparable among the four questions, they were converted into the percentage of respondents indicating “Yes.” For a given travel mode, there were four questions (i.e., positive impact on safety, positive impact on operations, negative impact on safety, negative impact on operations), with each question having one percentage value for each of the 16 technique categories. This percentage indicated the percentage of respondents indicating “Yes” to the question for the associated technique category. The responses for the technique category associated with Technique 1a (i.e., category 3) are listed in Table 75. For each travel mode, the percentages associated with the two mutually exclusive questions about safety (i.e., positive impact on safety, and negative impact on safety) were added. This sum represented the percentage of respondents that believed Technique 1a had an impact on the safety of the associated travel mode (the impact could be positive or negative). Similarly, the percentages associated with the two mutually exclusive questions about operations (i.e., positive impact on operations, and negative impact on operations) were added. The results of these additions are shown in the last column of the table for Technique 1a. This process was repeated for each of the other technique categories that were considered.

133 Table 75. Survey responses regarding safety or operations impact of Technique 1a. Impact by Performance Category and Mode Responses with “Yes” indication Percentage of all respondents Percent Indicating Some Impact 4. Adversely impacting safety of ped. mode 34 24.5 50.8 7. Positive safety impacts on ped. Mode 38 26.4 4. Adversely impacting safety of bike mode 21 15.1 38.0 7. Positive safety impacts on bike mode 33 22.9 4. Adversely impacting safety of bus mode 4 2.9 25.1 7. Positive safety impacts on bus mode 32 22.2 4. Adversely impacting safety of truck mode 1 0.7 21.5 7. positive safety impacts on truck mode 30 20.8 4. Adversely impacting operation of ped. mode 32 22.4 43.4 7. Positive operation impacts on ped. Mode 30 21 4. Adversely impacting operation of bike mode 17 11.9 33.6 7. Positive operation impacts on bike mode 31 21.7 4. Adversely impacting operation of bus mode 10 7 42.7 7. Positive operation impacts on bus mode 51 35.7 4. Adversely impacting operation of truck mode 8 5.6 39.9 7. Positive operation impacts on truck mode 49 34.3 For a given travel mode, the percentages in the last column of Table 75 were further combined to represent an estimate of the percentage of respondents that believe there is a safety impact, operational impact, or both. This percentage was computed using Equation 1. Equation 1 was used four times—once for each travel mode, as follows: , 100 1 1 0.01 50.8 1 0.01 43.4 72.2 , 100 1 1 0.01 38.0 1 0.01 33.6 58.8 , 100 1 1 0.01 25.1 1 0.01 42.7 57.1 , 100 1 1 0.01 21.5 1 0.01 39.9 52.8 Using Equation 1, the survey results were reduced to one equivalent response (i.e., some impact on safety, operations, or both) for each travel mode for a given technique category. This process was repeated for each of the other technique categories that were considered. In other words, for each travel mode, this technique produced one percentage value for each of the 16 technique categories. As a final step, the results from Equation 1 were combined into one response (per technique category) that reflected all four travel modes. Specifically, for a given technique category, the four percentages from Equation 1 were further combined to represent an estimate of the percentage of respondents that believe there is a safety impact, operational impact, or both on one or more modes. This percentage was computed using Equation 2. Equation 2 was used to compute the percentage of respondents that believe technique category 3 has an impact. This computation is shown below: Using this equation, the survey results were reduced to one

134 equivalent response (i.e., some impact on the safety, operations, or both of one or more modes). In other words, this technique produced one percentage value for each of the 16 technique categories. 100 1 1 0.01 72.2 1 0.01 58.8 1 0.01 57.1 1 0.01 52.8 97.7 This computation indicated that 97.7 of the respondents believe that the technique category associated with Technique 1a (i.e., category 3) has some impact on safety or operation of one or more of the four travel modes. Relative to the other 15 technique categories (identified in Table 71), the value 97.7 ranked sixth. Five of the technique categories received a larger percentage, implying more respondents believe the techniques associated with the other five have an impact. Information Need The survey included a question that asked the respondents to indicate their analysis needs and priorities for each of the technique categories. The question was focused on categories for which more information was needed about the associated techniques’ effect on the safety or operation of the pedestrian, bicycle, bus, or truck travel mode. The respondents were asked to identify the three categories for which more information was most needed. This question received 44 “Yes” responses for the technique category associated with Technique 1a (i.e., category 3). Relative to the other 15 technique categories (identified in Table 17), the 44 responses ranked first. None of the technique categories received more “Yes” responses, implying the respondents collectively believe that information is most needed for this technique category. Technique Category Utility The utility of each technique category was computed by first taking an average of the score (i.e., rank) for each of three components of utility. This average score was then subtracted from 17 (= total number of categories + 1) to produce a utility value that ranged from 1 to 16, with 16 used to indicate the category with the largest utility (i.e., most used, most likely to impact a non-auto mode, and for which information is most needed). The utility value was computed using Equation 3. For technique category 3, the utility was computed as follows: 17 8 6 13 12 Expected Technique Utility The utility score is intended to be an indication of the value that a newly developed performance relationship may indirectly provide to the traveling public by reliably informing decision-makers during the project development process. The “probability of success” was used to compute an expected utility for each technique. Specifically, the expected utility was computed by multiplying the utility value for each technique by the probability of success. This formulation is based on the assumption that the utility of the research results are “0.0” if the research is likely to be unsuccessful. The expected utility is computed using Equation 4. The computed utility, probability of success, and expected utility for each technique is listed in columns 2, 3, and 4, respectively, of Table 72. For Technique 1a, the probability of success was judged to be 1.0. As a result, the expected utility for Technique 1a was computed as: 12.0 1.0 12.0

135 Cost Assessment Procedure – Stage 1 The following example is used to illustrate the cost assessment for Technique 1a - Establish traffic signal spacing criteria. Table 70 indicates that the data source for the operations-based performance measures is simulation. The cost to develop the four operations relationships at the site analysis scale is estimated as $25,000, as shown in the first row of Table 73. However, two of the four possible operations-based performance relationships are indicated in Table 70 to be available in the literature (i.e., one or more studies were identified that quantified the effect of the technique on the operation of the pedestrian and bicycle modes). Therefore, the development cost was reduced (by ratio) to $12,500 (= 2/4 × $25,000). For Technique 1a, Table 70 indicates that the data source for the safety-based performance measures is “crash reports.” Based on Table 73, the cost to develop the four safety relationships at the site level using crash reports is estimated as $40,000. None of the four possible safety-based performance relationships are indicated in Table 70 to be available in the literature. Therefore, all four relationships would be developed using the $40,000 budget. The application scale is indicated in Table 70 to be “corridor.” Therefore, the corridor analysis scale is used to define the study area. This relatively large study area is assumed to double the cost of the site- level study. Thus, the cost of developing performance relationships for this technique is estimated as $105,000 (= 2 × [12,500 + 40,000]). This cost assessment procedure was used in Stage 1 to (1) verify that the cost of studying any individual technique would not exceed the available budget and (2) to estimate the total cost of studying the techniques moved forward from Stage 1 to Stage 2. All individual study costs were determined to be within the available budget; therefore, it was not necessary in Stage 1 to eliminate any techniques on the basis of study cost. Stage 2 – Final Selection of Techniques The objective of this stage was to reduce the list of techniques to include just those techniques for which developed performance relationships would be of maximum utility to practitioners while staying reasonably close to the available funds for this development. Specifically, the Stage 2 assessment identified the combination of techniques that maximize the total expected utility while not exceeding the funds available to the project. The researchers reviewed the techniques identified in this manner and used their judgment to refine the results. The estimates of development cost for the top 20 techniques selected in Stage 1 were refined in Stage 2 based on a more detailed evaluation of each technique. The refined development cost estimates were based on two sources of information. One source was the findings from a detailed review of the recent research literature that focused on identifying sound quantitative performance relationships. The second source was the findings from the development of a study design for each technique using the framework described in Chapter 3. The findings associated with these two sources are summarized in the next two subsections. The third subsection describes the refinements made to the cost assessment procedure. The fourth subsection describes the technique selection process. The recommended list of techniques from Stage 2 is described in the last subsection. Review of Research Literature The findings from a second, more in-depth, review of the literature were used to update the information in Table 70, as it related to the 20 techniques selected in Stage 1. The updated findings are shown in Table 76. The word “Yes” is shown in a table cell if one or more studies were identified that quantified the

136 effect of the technique on the corresponding travel mode. Those combinations of technique-and-mode for which a relationship was identified during the update are identified by the underlined “Yes” in Table 76. Table 76. Updated information about technique influence on operations and safety. Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale (Study Method4) Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty Primary Techniques Identified in NCHRP Report 420 1a. Establish traffic signal spacing criteria Yes Yes Yes Pos- sible Trend Trend Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports 1b. Establish spacing for unsignalized access Trend Yes Trend Pos- sible Yes Trend Pos- sible Pos- sible Corridor (C-S) Simula- tion Simula- tion 1c. Establish corner clearance criteria No No Pos- sible Pos- sible No No Pos- sible Pos- sible Site (C-S) Simula- tion Crash Reports 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median Yes Trend Yes Pos- sible Yes Yes Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports 2c. Close existing median openings Trend Trend Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Corridor (B-A) Simula- tion Crash Reports 2d. Replace full median opening with median designed for left turns from the major roadway Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Site (B-A) Simula- tion Simula- tion 3c. Install continuous two-way left-turn lane on undivided highway Yes Pos- sible Yes Pos- sible Yes Pos- sible Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports 3d. Install U-turns as an alternative to direct left turns Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Pos- sible Pos- sible Corridor (B-A) Simula- tion Simula- tion 4a. Install right-turn deceleration lane or right-turn lane Yes Trend Trend Trend Yes Yes Pos- sible Trend Site (B-A) Simula- tion Simula- tion 4b. Install continuous right-turn lane Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (B-A) Simula- tion Crash Reports 5a. Consolidate driveways Yes Trend No Pos- sible Trend Trend No Pos- sible Corridor (C-S) Simula- tion Simula- tion 5b. Channelize driveways to discourage or prohibit left turns on undivided highways Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Site (C-S) Field Simula- tion 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial– crossroad intersection Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (C-S) Simula- tion Crash Reports Selected Other Techniques Identified in NCHRP Report 420 B-3 Medians - Left Turns B-3-1 Install median barrier with no direct left-turn ingress or egress. Yes Pos- sible Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible Site (B-A) Simula- tion Simula- tion B-4 Right Turns B-4-6 Move sidewalk–driveway crossing laterally away from highway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (C-S) Field Field

137 Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale (Study Method4) Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty B-5 Access/Driveway Location–Retrofit Consolidation B-5-2-2 Require access on collector street (when available) in lieu of additional driveway on highway. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (B-A) Simula- tion Simula- tion B-5-2-3 Relocate or reorient access. Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (B-A) Simula- tion Simula- tion B-6 Traffic Controls B-6-8 Rep lace parallel on-street parking with off-street parking. Yes Yes Yes Pos- sible Pos- sible Yes Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports B-6-10 Install roundabout2 Yes Yes Yes Pos- sible Trend Pos- sible Pos- sible Pos- sible Site (B-A) Simula- tion Simula- tion B-7 Access/Driveway Design B-7-11 Improve driveway sight distance and B-7-12 Regulate minimum sight distance Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (C-S) Field Field Notes: 1 –Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team. 3 – Treatment effect indicators: “Yes” documented quantitative effect; “Trend” documented qualitative effect (but no documented quantitative effect); “Possible” no study found but possible effect; and “No” effect is unlikely or negligible. 4 – Study method: C-S = cross-sectional study; B-A = before–after study. The relationships identified in Table 76 were evaluated to assess the need for (and cost of) developing relationships suitable for practitioner implementation. In this regard, one of three status levels was assigned to each relationship identified in the literature. These levels are described in the following list.  Level “A” was assigned to relationships that are technically sound and documented in a manner suitable for direct use by a practitioner. No additional development effort would be needed in Project 03-120.  Level “B” was assigned to relationships that are technically sound, but not documented in a manner suitable for use by a practitioner. A small amount of Project 03-120 funds would be needed to describe the relationship in a format suitable for practitioner use.  Level “C” was assigned to relationships that are not sufficiently complete for practical application. A moderate amount of Project 03-120 funds would be needed to further develop the relationship and document it in a format suitable for practitioner use. The detailed findings and status level assignments from the review of recent research publications are documented in Appendix A (i.e., they are in the last column of Table 23 to Table 62 in Appendix A). These levels are not shown in Table 76 because, in some cases, there are multiple publications for a given travel mode and performance measure category.

138 Initial Study Design An initial study design was developed for each of the 20 techniques selected in Stage 1. The initial study design provided a study description and identified the major elements of the study design. The study description summarizes the study objectives, method, scope, and output results. The major elements of the study design include specification of the analysis scale, data source, independent variables, and performance measures. The activities involved in the development and documentation of an initial study design are described in Chapter 3. The key components of the study design for each technique are listed in the last three columns of Table 76. These components include the application scale, study method, and data source. The initial study design for each technique is provided in Appendix D. Analysis scale describes the spatial limits of the study area. The study area is dictated largely by the extent to which a technique has an effect on traffic operations or safety. In this regard, the analysis scale is often dictated by the technique’s application scale (i.e., the area over which the technique is typically applied). To facilitate study design development, the analysis scale was rationalized to match the application scale. Two study methods were considered, they include: before–after and cross-sectional. The before–after method is based on the assumption that there are no changes at the treated corridor or site, except for the implementation of the AM technique. This assumption is difficult to satisfy for corridor analyses (unless the data are obtained from a corridor simulation model) because agencies often make many changes to the roadway during a single resurfacing, rehabilitation, or reconstruction project. The cross-sectional study method is based on the use of a large database that collectively describes the traffic, road, and crash history of several corridors or sites. This method is based on the assumption that the differences in performance among the corridors or sites in the database can be explained by the differences in the measured variables associated with each corridor or site. There are several alternative sources of data that can be used to quantify the performance relationships. The sources considered for this project include: field measurements, simulation, and crash records. The choice of data source is influenced by the technique being studied and the performance measure category (i.e., operations or safety). For operations-based relationships, the more viable sources include field measurements and simulation. Field data include the measurement of traffic characteristic, roadway, and traffic control device data at one or more locations. Field data collection is expensive and time- consuming, relative to the budget and schedule of most projects. Simulation data would be obtained from an appropriate microscopic traffic simulation software product (e.g., VISSIM). Simulation is attractive because (1) the performance data are relatively cost-effective to acquire and (2) it allows the analyst to control changes in the traffic and roadway conditions similar to a before–after study. For safety-based performance relationships, viable sources of data include: crash reports, field measurements, and simulation. Crash reports may be either a summary crash record (possibly in electronic format) or a copy of the actual crash report, depending on the information needed to evaluate a specific technique. Field measurements and simulation can be used to quantify the number of vehicle-related conflicts for each travel mode of interest (e.g., vehicle-pedestrian conflicts). The challenge of using conflicts is that their relationship to crash frequency or severity is not typically known. This deficiency is true for the vehicle-related conflicts that are of interest to this project. If conflicts are used, some project resources should also be expended to investigate (and quantify if possible) the relationship between the measured conflicts and crash frequency or severity.

139 Refinements to the Cost Assessment Procedure The cost of developing the needed performance relationships for a given technique were reassessed for Stage 2 based on consideration of the analysis scale, study method, data source, number of unknown performance relationships, and the status level associated with each known relationship. The refined cost assessment procedure included some simplifying assumptions that provided sufficient accuracy to meet the objectives of Stage 2. One simplifying assumption is that a technique’s analysis scale is equivalent to its application scale. Another assumption, derived from past experience, is that the cost of developing relationships for a given technique using a corridor analysis scale is about twice the cost of developing relationships using a site analysis scale. Both of these assumptions were also used for estimating development costs in Stage 1. Several additional assumptions were made for the Stage 2 evaluation based on the experience of the research team. One assumption is that a before–after study method that uses field data has a cost that is 25 percent higher than the costs cited in Table 73. This increase is needed for the additional challenges encountered when identifying study sites, coordinating the technique implementation with the responsible agency, and collecting data in a timely manner during the “before” and “after” study periods. For similar reasons, it was also assumed that a before–after study method that uses reported crash data has a cost that is 5 percent higher than the costs in Table 73. This increase is needed for (1) obtaining and reviewing crash reports, and (2) the additional challenges encountered when identifying study sites for which the technique has been implemented in the recent past (and no other changes were made). Another assumption is that the development cost of a performance relationship for a specific technique- and-mode combination is a function of its status level (i.e., A, B, or C), as described previously (in the text following Table 76). The association between status level and cost is expressed as a percentage of the cost of developing a quantitative relationship that is not documented in the literature. It is assumed that 0, 30, and 70 percent describe the relative development cost for status levels A, B, and C, respectively. For example, assume a relationship costs $25,000 to develop from newly collected data. However, if a relationship is found in the literature and it is assigned a status level “B” then the development cost is estimated as $7,500 (= 0.3 × $25,000). For a given technique, the initial cost estimate of developing performance relationships at the “site” analysis scale is listed in Table 73. Each cost listed in the table represents the cost of developing the four performance relationships (one for each non-auto mode) for a given performance measure category (i.e., operations or safety). When the literature review indicated that less than four performance relationships would need to be developed for a given technique and performance measure category, the development cost was computed as follows: one-half of the cost listed in Table 73 was assumed to be the base cost of the study regardless of the number of relationships developed. The other one-half of the cost listed in Table 73 was divided among the four possible relationships. If less than four relationships were developed, then this one-half of the cost was reduced proportionally. For example, if four safety relationships based on crash reports are needed, Table 73 indicates the development cost is $40,000. However, if only one safety relationship is needed (because those for the other three travel modes are available in the literature) then the cost is estimated as $25,000 (= $40,000/2 + $40,000/[2 × 4 relationships] × 1 relationship developed). In this manner, the cost of the study can be estimated as $25,000, $30,000, $35,000, or $40,000 when 1, 2, 3, or 4 relationships are developed, respectively, using crash reports. The computed development cost for each technique is listed in column 7 of Table 77. The total cost indicated at the top of this column (i.e., $1,521,000) is less than that shown in column 7 of Table 74. This reduction reflects the revised procedure for estimating technique development costs and the fact that additional performance relationships were identified in the literature during Stage 2.

140 Table 77. Estimated utility and development cost by technique for Stage 2. Technique (listed by ID code1) All Techniques Selected Techniques U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity Available Relationships C os t o f S tu dy Te ch ni qu e Se le ct ed To ta l U til ity To ta l C os t O pe ra tio n Sa fe ty Total: 223.0 $1,521,000 10 131.3 $595,875 Primary Techniques Identified in NCHRP Report 420 1a. Establish traffic signal spacing criteria 12.0 1.0 12.0 1 4 $92,500 1 12.0 $92,500 1b. Establish spacing for unsignalized access 13.7 1.0 13.7 3 3.3 $98,500 1 13.7 $98,500 1c. Establish corner clearance criteria 13.7 1.0 13.7 4 4 $48,750 1 13.7 $48,750 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median 14.0 1.0 14.0 2 2.6 $103,500 0 0.0 $0 2c. Close existing median openings 14.0 1.0 14.0 4 3 $123,500 0 0.0 $0 2d. Replace full median opening with median designed for left turns from the major roadway 14.0 1.0 14.0 4 3 $51,250 1 14.0 $51,250 3c. Install continuous two-way left-turn lane on undivided highway 5.3 1.0 5.3 2 3.3 $110,500 0 0.0 $0 3d. Install U-turns as an alternative to direct left turns 14.0 1.0 14.0 3.7 4.0 $108,125 0 0.0 $0 4a. Install right-turn deceleration lane or right-turn lane 9.3 1.0 9.3 3 2.3 $45,500 1 9.3 $45,500 4b. Install continuous right-turn lane 9.3 1.0 9.3 4 4 $67,000 0 0.0 $0 5a. Consolidate driveways 8.7 1.0 8.7 3 4 $90,000 0 0.0 $0 5b. Channelize driveways to discourage or prohibit left turns on undivided highways 7.0 1.0 7.0 4 3 $61,250 0 0.0 $0 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection 13.7 1.0 13.7 1 4 $55,625 1 13.7 $55,625 Selected Other Techniques Identified in NCHRP Report 420 B-3 Medians - Left Turns B-3-1 Install median barrier with no direct left-turn ingress or egress. 14.0 1.0 14.0 3 3 $48,125 1 14.0 $48,125 B-4 Right Turns B-4-6 Move sidewalk–driveway crossing laterally away from highway. 1.0 1.0 1.0 4 4 $80,000 0 0.0 $0 B-5 Access/Driveway Location – Retrofit Consolidation B-5-2-2 Require access on collector street (when available) in lieu of additional driveway on highway. 13.7 1.0 13.7 4 4 $55,000 1 13.7 $55,000 B-5-2-3 Relocate or reorient access. 13.7 1.0 13.7 4 4 $55,000 1 13.7 $55,000 B-6 Traffic Controls B-6-8 Replace parallel on-street parking with off-street parking. 7.7 1.0 7.7 1 3 $101,250 0 0.0 $0 B-6-10 Install roundabout2 13.7 1.0 13.7 1 4 $45,625 1 13.7 $45,625 B-7 Access/Driveway Design B-7-11 Improve driveway sight distance and B-7-12 Regulate minimum sight distance 10.7 1.0 10.7 4 4 $80,000 0 0.0 $0 Notes:

141 1 – Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team. Selection Process An initial set of 10 techniques was identified that produced the largest total utility for a specified total cost. A procedure was developed to identify these techniques. The procedure incorporated an optimization algorithm with the objective to maximize the total expected utility. The key constraint was that the total cost of developing all selected techniques could not exceed the specified total cost. The simplex algorithm in Excel was used to automate the procedure. The algorithm evaluated alternative subsets of the 20 techniques. The procedure reported the one subset that had the maximum total expected utility while not exceeding the specified total cost constraint. The funds available in Phase 2 for relationship development were estimated as $325,000. The specified total cost constraint used to identify the initial set of 10 techniques was estimated to be $600,000. This value was set to equal the available funds multiplied by 1.85. The factor 1.85 resulted in the identification of more techniques than could be funded, but it also ensured that truly viable techniques were not overlooked by relying too heavily on the optimization algorithm for selection. The 10 techniques selected in this manner are identified in column 8 of Table 77 by the number “1”. The 10 techniques that were identified using the $600,000 specified total cost constraint were then reviewed by the researchers to identify the final set of techniques recommended for further consideration in Stage 3. During this review, the researchers used their judgment and experience to identify the techniques for which (1) performance information is most needed by practitioners and (2) the total development cost was nearly equal to the Phase 2 budget of $325,000. Six of the 10 techniques were selected for Stage 3 consideration as a result of this review. They are described in the next section. Selection Results The six techniques for which information is needed by practitioners and that can be accommodated within the project resources are identified in Table 78. The estimated cost to develop performance relationships for these techniques was approximately $336,125. This cost slightly exceeded the $325,000 budget for Phase 2. However, it was sufficiently close for this planning phase of the project.

142 Table 78. Techniques selected in Stage 2. Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Selected Techniques the Operation (or LOS) of... the Safety of... Te ch ni qu e Se le ct ed Ex pe ct ed U til ity C os t o f S tu dy Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k Total: 6 76.3 $336,125 Primary Techniques Identified in NCHRP Report 420 1a. Establish traffic signal spacing criteria Yes Yes Yes Pos- sible Trend Trend Pos- sible Pos- sible 1 12.0 $92,500 1c. Establish corner clearance criteria No No Pos- sible Pos- sible No No Pos- sible Pos- sible 1 13.7 $48,750 4a. Install right-turn deceleration lane or right-turn lane Yes Trend Trend Trend Yes Yes Pos- sible Trend 1 9.3 $45,500 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial– crossroad intersection Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible 1 13.7 $55,625 Selected Other Techniques Identified in NCHRP Report 420 B-3 Medians - Left Turns B-3-1 Install median barrier with no direct left-turn ingress or egress. Yes Pos- sible Pos- sible Pos- sible Pos- sible Yes Pos- sible Pos- sible 1 14.0 $48,125 B-6 Traffic Controls B-6-10 Install roundabout2 Yes Yes Yes Pos- sible Trend Pos- sible Pos- sible Pos- sible 1 13.7 $45,625 Notes: 1 –Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team. 3 – Treatment effect indicators: “Yes” documented quantitative effect; “Trend” documented qualitative effect (but no documented quantitative effect); “Possible” no study found but possible effect; and “No” effect is unlikely or negligible. The specific performance relationships to be developed are also identified in Table 78. These relationships are indicated by the cells containing the words “Possible” or “Trend.” There are 30 relationships identified in this manner. For example, for Technique 1a – Establish traffic signal spacing criteria, there are five relationships planned for development. Collectively, they can be used to evaluate: truck operations, pedestrian safety, bicycle safety, transit safety, and truck safety. For Technique 1a, relationships for pedestrian operations, bicycle operations, and transit operations are indicated in Table 78 to be available in the literature (i.e., they are identified by the cells with the word “Yes”) so they were not planned for development in Phase 2. The source documents that describe these existing relationships are identified in Appendix A. Stage 3 – Detailed Assessment of Selected Techniques The objective of this stage was to develop a prioritized list of techniques for which performance relationships could be developed in Phase 2. The techniques considered in this section are the six techniques identified at the end of the Stage 2 assessment and summarized in Table 78. The six techniques identified in Table 78 were prioritized because it was recognized that the total cost of developing all corresponding relationships could exceed the funds available to the project. The priority

143 rank was assigned on a technique-by-technique basis, with consideration of the utility of the collective set of associated performance relationships. This approach recognized that an economy-of-scale was likely to be realized when research is undertaken to develop all needed relationships for a given technique. The expected utility score and the estimated development cost were used to determine the priority rank for each technique. The utility-to-cost ratio was used to define the cost effectiveness of developing relationships for a given technique. The technique with the largest ratio was determined to be the most cost-effective technique, so it was given a rank of 1. The technique with the next highest ratio was given a rank of 2, and so on for the remaining techniques. The ranked list of techniques is provided in Table 79. Table 79. Prioritized list of techniques to evaluate in Phase 2. Technique (listed by ID code1) Selected Techniques Rank Expected Utility Cost of Study Ratio3 Total: 76.3 $336,125 B-6-10 Install roundabout2 1 13.7 $45,625 0.30 B-3-1 Install median barrier with no direct left-turn ingress or egress. 2 14.0 $48,125 0.29 1c. Establish corner clearance criteria 3 13.7 $48,750 0.28 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection 4 13.7 $55,625 0.25 4a. Install right-turn deceleration lane or right-turn lane 5 9.3 $45,500 0.21 1a. Establish traffic signal spacing criteria 6 12.0 $92,500 0.13 Notes: 1 – Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team. 3 – Ratio = expected utility / cost of study × 1000. Assessment of Supplemental Techniques The recommended techniques listed in Table 79 were discussed with the project panel at an interim point of the project. The panel identified four additional techniques to be considered for study in Phase 2. The panel requested an assessment of these techniques using the process that was used to prioritize the techniques in Table 79. The four techniques that the panel identified include:  Two-way left-turn lane (TWLTL) versus restrictive (i.e., non-traversable) median, to include: o Install TWLTL on undivided highway o Install non-traversable median on highway with TWLTL o Install non-traversable median on undivided highway  Replace curb parking with off-street parking  Install appropriate driveway width and radius  Limit access in the functional intersection area (signalized) Review of Research Literature Each of the four techniques identified by the panel was judged to be very similar to one or two of the original 74 techniques. As a result, the findings from the original assessment process were used as the basis for assessing the four supplemental techniques. The four techniques and their corresponding original techniques are listed in the first two columns of Table 80.

144 Table 80. Information about influence of supplemental techniques on operations and safety. Supple- mental Technique Original Technique (listed by ID code1) Does Technique Implementation have an Effect on...3 Appli- cation Scale (Study Method4) Data Source the Operation (or LOS) of... the Safety of... Pe de st ria n B ik e Tr an si t Tr uc k Pe de st ria n B ik e Tr an si t Tr uc k O pe ra tio ns Sa fe ty TWLTL vs. non- traversable median 2a.& 2b. Install non- traversable median on undivided highway and replace TWLTL with non- traversable median Yes Trend Yes Pos- sible Yes Yes Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports 3c. Install continuous two-way left-turn lane on undivided highway Yes Pos- sible Yes Pos- sible Yes Pos- sible Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports Replace curb parking with off-street parking B-6-8 Rep lace parallel on- street parking with off-street parking. Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Corridor (C-S) Simula- tion Crash Reports Install appropriate driveway width and radius Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 Trend Trend Trend Trend Trend Trend Pos- sible Pos- sible Site (C-S) Simula- tion Simula- tion Limit access in the functional intersection area 1c. Establish corner clearance criteria No No Pos- sible Pos- sible No No Pos- sible Pos- sible Site (C-S) Simula- tion Crash Reports 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial– crossroad intersection Yes Yes Yes Pos- sible Pos- sible Pos- sible Pos- sible Pos- sible Site (C-S) Simula- tion Crash Reports Notes: 1 – Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team. 3 – Treatment effect indicators: “Yes” documented quantitative effect; “Trend” documented qualitative effect (but no documented quantitative effect); “Possible” no study found but possible effect; and “No” effect is unlikely or negligible. 4 – Study method: C-S = cross-sectional study; B-A = before–after study. The findings from a review of the literature are identified in Table 80. The quantitative performance relationships that were found in the literature are indicated by the word “Yes” in the table cells. The word “Yes” is shown if one or more studies were identified that quantified the effect of the technique on the corresponding travel mode. Initial Study Design An initial study design was developed for each of the techniques identified in Table 80. The initial study design provided a study description and identified the major elements of the study design. The study description summarizes the study objectives, method, scope, and output results. The major elements of the study design include specification of the analysis scale, data source, independent variables, and performance measures. The key components of the study design for each technique are summarized in the last three columns of Table 80. These components include the analysis scale, study method, and data source. The initial study design for each technique is provided in Appendix D.

145 Utility Assessment Procedure The utility assessment procedure consisted of the use of survey results to develop a score for each of the three components of utility. The utility was then based on the average of the three scores. The utility value for each technique ranges from 1 to 16. A higher value of utility represents a technique that is more helpful to practitioners (i.e., most used, most likely to impact a non-auto mode, and for which information is most needed). The cost of developing the needed performance relationships for a given technique was estimated based on consideration of the technique analysis scale (i.e., application scale), proposed source of data, and number of unknown relationships for the technique. Assessment Results for Four Techniques The computed utility and development cost for each of the four techniques is listed in Table 81. The techniques listed in this table are not ranked; their order of presentation does not imply any priority of one technique relative to another. The estimated total development cost for the four techniques was $474,625. Table 81. Estimated utility and development cost for four supplemental techniques. Supplemental Technique Original Technique (listed by ID code1) Original Technique New Techniques Ex pe ct ed U til ity C os t o f S tu dy U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity C os t o f S tu dy R at io 2 Total: 57.8 $474,625 57.8 $474,625 TWLTL vs. non- traversable median 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non- traversable median 14.0 $103,500 19.3 1.0 19.3 $214,000 0.09 3c. Install continuous two-way left-turn lane on undivided highway 5.3 $110,500 Replace curb parking with off- street parking B-6-8 Rep lace parallel on-street parking with off- street parking. 7.7 $101,250 7.7 1.0 7.7 $101,250 0.08 Install appropriate driveway width and radius Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 3.5 $55,000 7.0 0.5 3.5 $55,000 0.06 Limit access in the functional intersection area 1c. Establish corner clearance criteria 13.7 $48,750 27.3 1.0 27.3 $104,375 0.26 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection 13.7 $55,625 Note: 1 – Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Ratio = expected utility / cost of study × 1000. With one exception, the probability of success for all techniques is 1.0. The technique install appropriate driveway width and radius is associated with a probability of 0.5. The original technique was assigned a probability of 0.0 (see Table 72). This lower probability of success relates to the relatively subtle effect of driveway width and radius on the operation or safety of pedestrian, bicycle, or truck

146 travel, combined with the relatively low pedestrian, bicycle, and truck volumes at driveway in suburban areas (where variations in driveway width and radius are typically found). The probability was raised to 0.5 for Table 81 based on study design guidance offered by the panel. Column 7 of Table 81 shows the expected utility associated with the four new techniques. The total expected utility of the performance relationships is 57.8. For the two new techniques that are each based on two original techniques, the total expected utility was computed as the sum of the utility for each of the two original techniques. For example, for the TWLTL vs. non-traversable median technique, the two original techniques had utilities of 14.0 and 5.3; their total utility is 19.3. This summation of the utilities of the original techniques (to estimate the utility of the new/combined technique) recognizes that the new technique delivers the products associated with both of the original techniques. Hence, in terms of maximizing the total utility of all projects selected for Phase 2 (as was the objective in Stage 1 and Stage 2), the conduct of Technique “2a & 2b” and Technique “3c” yields a total utility of 19.3, regardless of whether Technique “2a & 2b” and “3c” are undertaken as separate development projects, or as one combined project. The expected utility values for the two new/combined projects are relatively high, which suggest they may be very helpful to practitioners. However, their development cost is also relatively high, such that the new/combined techniques are not as attractive as any of the six techniques identified in Table 79 when expressed on a utility-to-cost ratio basis. Final Assessment and Prioritization of Techniques A follow-up meeting was convened with the panel to discuss the recommended six techniques listed in Table 79 and the four new techniques in Table 81. This discussion led to the panel’s ranking of these techniques in order of priority for Phase 2 research. The decisions reached by the panel during this meeting are summarized in this section. One technique (i.e., 1c-Establish corner clearance criteria) was common to the two lists in Table 79 and Table 81. As a result, there were nine uniquely titled techniques in the combined list. This combined list is provided in Table 82. The first column of the table lists the “short title” for each technique. This title was used during the panel meeting. The third column lists the corresponding original title.

147 Table 82. Final list of techniques for further study in Phase 2. Short Title Supplemental Technique Original Technique (listed by ID code1) Appli- cation Scale (Study Method3) Data Source O pe ra tio ns Sa fe ty Driveway design Install appropriate driveway width and radius Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 Site (C-S) Simula- tion Field Simula- tion Crash Reports Right-turn deceleration -- 4a. Install right-turn deceleration lane or right-turn lane Site (B-A) Simula- tion Simula- tion TWLTL vs. non- traversable median TWLTL vs. non-traversable median 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median Corridor (C-S) Simula- tion Crash Reports 3c. Install continuous two-way left-turn lane on undivided highway Corner clearance Limit access in the functional intersection area (Part 1) 1c. Establish corner clearance criteria Site (C-S) Simula- tion Crash Reports Signal spacing -- 1a. Establish traffic signal spacing criteria Corridor (C-S) Simula- tion Crash Reports Median barrier w/no lefts -- B-3-1 Install median barrier with no direct left-turn ingress or egress. Site (B-A) Simula- tion Simula- tion Replace parking Replace curb parking with off- street parking B-6-8 Rep lace parallel on-street parking with off-street parking. Corridor (C-S) Simula- tion Crash Reports Relocate access Limit access in the functional intersection area (Part 2) 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection Site (C-S) Simula- tion Crash Reports Roundabout -- B-6-10 Install roundabout2 Site (B-A) Simula- tion Simula- tion Notes: 1 –Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team. 3 – Study method: C-S = cross-sectional study; B-A = before–after study. Based on guidance from the panel, revisions were made to the study design for three techniques. The revised study designs are provided near the end of Appendix D, in the section titled Study Designs for Supplemental Techniques. The first revised study was that for the Driveway Design technique, as listed in Table 82. The study design for this technique was revised such that (1) field data would be used for the operations study component, (2) field-measured conflict data and crash data would be used for the safety study component, and (3) the study would examine only the pedestrian and bicycle travel modes. These changes were made to improve the probability of success for the overall study. They reflect a concern that simulation models are not well-suited to the analysis of driveway operation or safety for pedestrians, bicycles, transit vehicles or trucks. These changes are recognized in the last two columns of the table using strikeout font. The second revised study was that for the TWLTL vs. non-traversable median technique. The scope of this study was revised to exclude the need to study the undivided cross section. Rather, the study would focus on developing performance relationships for just the TWLTL cross section and the non-traversable median cross section. This change in study scope is indicated by strikeout font in column 3 of Table 82. The third revised study was that for the corner clearance technique. The scope of this study was expanded to include consideration of the pedestrian and bicycle travel modes. As indicated in columns 3,

148 4, 7, and 8 of Table 80 (and prior versions of this table), corner clearance was not believed to have an effect on the operation or safety of pedestrian and bicycle modes. However, members of the panel felt that there may be an effect of corner clearance on these two travel modes and that the study should include the cost of investigating this effect. As a result, the study scope was expanded to include the cost of developing performance relationships for all eight combinations of travel mode and performance measure category. This change doubled the number of performance relationships planned for development in this study. The cost of developing the needed performance relationships for a given technique was estimated based on consideration of the technique analysis scale (i.e., application scale), proposed source of data, and number of unknown relationships for the technique. The procedures for calculating the utility and development cost for a technique are described in a previous section. The application scale, data source, and study method for the nine techniques are provided in the last three columns of Table 82. The computed utility and development cost for each of the nine techniques is listed in Table 83. The estimated total development cost for the nine techniques is $654,275. Table 83. Utility and development cost for final list of techniques. Short Title Supplemental Technique Original Technique (listed by ID code1) U til ity Pr ob ab ili ty o f Su cc es s Ex pe ct ed U til ity C os t o f S tu dy A cc um ul at ed C os t Total: 101.5 $654,275 Driveway design Install appropriate driveway width and radius Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 7.0 0.5 3.5 $55,000 $75,000 $75,000 Right-turn deceleration -- 4a. Install right-turn deceleration lane or right-turn lane 9.3 1.0 9.3 45,500 $120,500 TWLTL vs. non- traversable median TWLTL vs. non-traversable median 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median 19.3 14.0 1.0 19.3 14.0 $214,000 $93,150 $213,650 3c. Install continuous two-way left-turn lane on undivided highway Corner clearance Limit access in the functional intersection area (Part 1) 1c. Establish corner clearance criteria 13.7 1.0 13.7 $48,750 $97,500 $311,150 Signal spacing -- 1a. Establish traffic signal spacing criteria 12.0 1.0 12.0 $92,500 $403,650 Median barrier w/no lefts -- B-3-1 Install median barrier with no direct left-turn ingress or egress. 14.0 1.0 14.0 $48,125 $451,775 Replace parking Replace curb parking with off-street parking B-6-8 Rep lace parallel on-street parking with off-street parking. 7.7 1.0 7.7 $101,250 $553,025 Relocate access Limit access in the functional intersection area (Part 2) 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterial–crossroad intersection 13.7 1.0 13.7 $55,625 $608,650 Roundabout -- B-6-10 Install roundabout2 13.7 1.0 13.7 $45,625 $654,275 Notes: 1 –Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 – Technique added or modified by the NCHRP 03-120 research team.

149 Further discussion occurred at the panel meeting to identify those techniques for which (1) performance information is most needed by practitioners and (2) the total development cost was nearly equal to the Phase 2 budget of $325,000. After this discussion, a series of straw polls were taken of the panel members to identify the relative priority of the nine techniques. The priorities that were established in this manner are indicated in Table 83 by the order in which the techniques are listed. The techniques listed in this table in ranked order of priority, from top to bottom. The technique in the first row of the table was given highest priority. The accumulated cost of the ranked techniques is provided in the last column of Table 83. This column was used to identify the number of technique studies that could be undertaken in Phase 2, given that $325,000 was available for this purpose. Examination of this column indicates that the estimated development cost for the first four techniques nearly equals the available $325,000. The difference of $13,850 (=325,000 – 311,150) between the available budget and the accumulated cost for the four highest priority techniques was used as a contingency fund to accommodate unforeseen costs associated with the development of performance relationships for the four techniques. It was also noted by the panel and research team that final study designs and associated resource needs for these four techniques may further reduce the number of treatment ultimately examined in Phase 2. Resources were not believed to be sufficient to develop performance relationships for the last five techniques listed in Table 83. These techniques are identified by grey shaded cells in the table. They are described in Chapter 5 as areas deserving of future research. A final study design for each technique was developed at the start of Phase 2. The final study design expanded upon the initial study designs by identifying site selection factors, potential test sites, specific database variables, sample sizes, and data collection techniques suitable for quantifying the specified performance relationships. The final study designs are provided in Appendix E.

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Assessing Interactions Between Access Management Treatments and Multimodal Users Get This Book
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TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 256: Assessing Interactions Between Access Management Treatments and Multimodal Users describes operational and safety relationships between access management techniques and the automobile, pedestrian, bicycle, public transit, and truck modes. This contractor's report may help assist in the selection of alternative access management techniques based on the safety and operation performance of each affected travel mode.The roadway system must accommodate many types of users—bicyclists, passenger cars, pedestrians, transit, and trucks. This report examines the interactions between multimodal operations and access management techniques and treatments, and the trade-off decisions that are necessary.

NCHRP Research Report 900: Guide for the Analysis of Multimodal Corridor Access Management accompanies this report.

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