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Separation of Vehicles—CMV-Only Lanes (2010)

Chapter: Chapter 4 - Benefit-Cost Analysis

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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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Suggested Citation:"Chapter 4 - Benefit-Cost Analysis." National Academies of Sciences, Engineering, and Medicine. 2010. Separation of Vehicles—CMV-Only Lanes. Washington, DC: The National Academies Press. doi: 10.17226/14389.
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58 The previous chapter demonstrated from prior analyses that there are truck-only lane config- urations that, in different types of corridors, can provide positive benefits that meet regional and corridor planning objectives. The chapter also was able to identify some patterns in the types of truck-only lanes that have the highest level of benefits in different scenarios, as well as the key variables that drive benefits. Nonetheless, there were some serious shortcomings when it comes to drawing definitive con- clusions about the performance benefits and feasibility of truck-only lanes. Some of the most important shortcomings included the following: • Lack of a complete set of appropriate alternatives. The most obvious example of this prob- lem is cases in which mitigating congestion was an objective but the study did not examine an alternative that added capacity that was not a truck-only alternative. Congestion reduction benefits of truck-only lanes were often based on comparison with doing nothing (no-build alternative). Also, in some of the cases where additional mixed-flow lanes were considered in the alternatives analysis, there were differences in capacities between the mixed-flow and truck-only lane alternatives, due to which, the performance results were inconclusive in assess- ing the actual benefits of truck-only lanes relative to additional mixed-flow lanes. • Not taking into account an appropriate range of values for key variables. For example, to the extent that diversion to LCV configurations has a direct impact on the productivity ben- efits of LCV lanes, no studies did a market assessment for LCVs to determine which truck trips/ commodity flows would represent real candidates for diversion. In many cases, diversion sce- narios for trucks from general purpose to truck-only lanes looked unrealistically high. • Inability to measure all benefits with a single metric (such as monetized values) so that rel- ative importance of benefits across types (e.g., travel time savings, reliability, and safety) and relationships between benefits and costs can be assessed. Benefit-cost (B-C) analysis is needed to complete the assessment of overall economic feasibility. • Lack of important tools necessary to analyze specific truck-only lane benefits. Studies relied heavily on traditional travel demand models and relationships between V/C ratios and other performance measures. Tools such as traffic simulation models could have enhanced the effort to examine actual travel times, incident-related delay, reliability, and potential safety benefits of truck-only lanes. • Lack of data on specific performance changes when trucks and autos are separated. Changes in traffic flows and speeds and crash rates that are a direct function of the operational improve- ments of separating trucks and autos were not included in any of the analysis because there is so little field data with which to estimate these specific benefits. To the extent that data are available, they are usually associated with auto-only lanes and not with truck-only lanes. This section attempts to address the first three shortcomings to a limited degree through devel- opment of a “generic corridor” analysis framework for the B-C analysis of truck-only lanes. C H A P T E R 4 Benefit-Cost Analysis

Benefit-Cost Analysis 59 4.1 Benefit-Cost Analysis Approach As noted in the previous section, a B-C analysis would have allowed for the assessment of the relative importance of different types of benefits for any given scenario/alternative for truck-only lane application. It also would have allowed for a determination of which configurations appear to deliver the highest level of net benefits after taking costs into account. This is particularly important when comparing LCV versus non-LCV operations on truck-only lanes since costs may be higher for LCV systems off-setting some of the productivity benefits. Yet, most of the studies reviewed for the performance evaluation task did little to assess the cost-effectiveness of truck-only lanes compared to other alternatives (such as additional mixed-flow lanes) based on the development of B-C ratios. Due to this constraint, alternative approaches were developed for the B-C analysis in this study. The approach that was taken in this study was to define a representative baseline (generic) cor- ridor for each of the two scenarios/corridor types (long-haul intercity and urban), to apply the approaches and data provided by the previously reviewed studies, use standard values from the literature to monetize benefits, and use data from the prior studies to estimate costs. The B-C analysis was based on a net present value (NPV) analysis approach, which is described below. 4.1.1 Net Present Value Analysis The B-C analysis was based on an NPV analysis approach using a base year of 2008 and a time horizon of 2030 for the analysis. Monetized benefits and costs were estimated for each year in the 2008 through 2030 time period and discounted to the base year (2008) to get the NPV of B-C ratios for each alternative. Benefits were calculated for a similar set of performance measures as those evaluated in the reviewed studies. The benefits were monetized using monetary values for travel times and reliability (using auto and truck value of time estimates) and monetary val- ues for accidents (by type of accident). Costs were calculated based on unit cost factors devel- oped from the literature (a detailed discussion of the benefit monetization factors and unit costs is presented in Appendix C, which is available on the TRB website at www.TRB.org by search- ing for NCHRP Report 649/NCFRP Report 3, and summarized later in this chapter). A later sec- tion describes the traffic growth and other economic assumptions used for the NPV analysis. As described earlier, representative baseline corridors were defined for the B-C analysis, so that the relative benefits-costs of truck-only lanes in different corridor applications could be eval- uated. The following section describes the corridor concepts defined for the B-C analysis. 4.1.2 Representative Baseline Corridors The representative baseline corridors defined for the B-C analysis are not actual corridors but are generic corridors, that provided us with the opportunity to control characteristics of the cor- ridors for analysis purposes. Although not actual corridors, the characteristics (e.g., auto and truck traffic volumes, length of corridor, and number of lanes) are derived from actual corridors evaluated for truck-only lanes throughout the country. Readers should view the B-C ratios calcu- lated with this approach with some caution as they are not based on detailed analysis using data from actual corridors. However, for comparative purposes, and to give an idea of the range of assump- tions that would make truck-only lanes a preferred alternative, the approach is useful. For each baseline corridor scenario (long-haul and urban), a set of general corridor and traffic characteristics were defined. These characteristics included the following: • Length of corridor, • Number of lanes and capacity, and • Total average daily traffic (ADT) and heavy-truck ADT.

60 Separation of Vehicles—CMV-Only Lanes For each baseline corridor scenario, a set of meaningful alternatives was defined including a truck-only lane alternative (which included two operational scenarios—with and without LCVs— in the case of a long-haul corridor), a mixed-flow lane alternative (to assess the relative benefits and costs of truck-only lanes compared to additional mixed-flow lanes), and a no-build alternative. Subsequent sections provide a more detailed description of the alternatives considered within each corridor scenario. Because the data inputs for the B-C analysis for the urban and long-haul corridor scenarios have a high degree of uncertainty associated with them (such as costs and factors impacting truck diversion rates), and the magnitude of this uncertainty is unknown, the study team felt uncom- fortable computing a single B-C ratio for each alternative. In order to recognize uncertainty in key input variables, a sensitivity analysis approach was used for the B-C analysis, which is described below. 4.1.3 Sensitivity Analysis Approach To capture some of the uncertainties involved in the range of factors driving the diversion of truck traffic to truck-only lanes (which have a direct impact on the performance benefits estimates of truck lanes), as well as the uncertainties in capturing the range of costs for truck-only lane proj- ects, a sensitivity analysis approach was used for the B-C analysis. A key variable in the analysis is the assumption about how much truck traffic diverts to the truck-only lanes. In the case of truck- only lanes without LCV operations, diversion rates should be a function of the relative congestion conditions on the mixed-flow lanes (assuming trucks are not required to operate on the truck-only lanes), number and placement of the exits and entrances to the truck-only lanes (and an associated cost tradeoff), and the O-D patterns of the trucks. In the case of truck-only lanes with LCV oper- ations, diversion rates are expected to be a function of the connectivity to a larger LCV network, commodities carried (not all commodities will benefit from LCV operations), O-D patterns of the trucks, and off-system infrastructure availability (staging areas) and costs of LCV operations. None of the performance evaluations of LCV operations described in the previous chapter have con- ducted this type of thorough evaluation of the LCV market opportunities and they have tended to assume very high levels of trucks diverting to LCVs. However, analysis conducted for the I-15 Com- prehensive Corridor Study in Southern California and analysis underway at the time of this study of potential LCV operations in the I-80/90 corridor between Chicago and Boston conducted for FHWA suggest that the markets for LCV operations in real corridors might be considerably smaller than previous studies have assumed. Therefore, the sensitivity analysis involved consider- ing a range of diversion rates and assessing the impact of diversion rates on B-C ratios. The sensi- tivity analysis also considers the uncertainty in cost estimates and varies these in order to take into account potentially missing cost elements or certain widely varying unit cost factors reported in the literature. For long-haul corridors, the sensitivity analyses included the following: • Variations in rates of diversion to LCV lanes and truck-only lanes without LCVs, and • Variations in costs. For urban corridors the sensitivity analyses included the following: • Variations in rates of diversion to truck-only lanes, and • Variations in costs. The sensitivity analysis approach for the B-C analysis of truck-only lanes along long-haul and urban corridors is useful in gaining the following key insights: • Assessing the range of diversion rates that would result in truck-only lanes being cost-effective in comparison to adding mixed-flow capacity;

Benefit-Cost Analysis 61 • Assessing what the minimum level of diversion would need to be in the case of LCV opera- tions to make truck-only lanes a viable investment option in comparison to additional mixed- flow lanes; • Assessing optimal diversion rates for truck-only lanes that provide the highest levels of cost- effectiveness (for congested corridors with high truck volumes, very high diversion rates would not necessarily maximize cost-effectiveness since congestion reduction on the general purpose lanes due to truck diversion might be offset by high levels of congestion on the truck- only lanes—this would be particularly relevant in the case where use of the truck-only lanes is mandatory); and • Assessing the differences in diversion rates required for truck lanes with and without LCV operations to achieve similar levels of cost-effectiveness in the case of long-haul corridors. 4.2 Performance Metrics Considered for Benefit-Cost Analysis The performance metrics discussed in the remainder of the following subsections were con- sidered for the B-C analysis of truck-only lanes. 4.2.1 Public Benefits Public benefits could include the following: • Travel time savings that accrue to autos on general purpose lanes as trucks divert from general purpose lanes to truck-only lanes, thereby reducing congestion and improving travel speeds on the general purpose lanes. This metric is typically evaluated in terms of percent savings in travel times on the general purpose lanes due to the implementation of truck-only lanes. • Reliability benefits that accrue to autos on general purpose lanes due to the implementation of truck-only lanes. The diversion of trucks to truck-only lanes reduces congestion and truck- auto interaction on the general purpose lanes, thereby improving safety and providing asso- ciated reliability benefits (in terms of reduction in incident-related nonrecurrent delay). This metric is typically evaluated in terms of percent savings in incident-related (nonrecurrent) delay on general purpose lanes due to the implementation of truck-only lanes. • Safety benefits that accrue to all users. As discussed previously, the implementation of truck- only lanes can provide safety benefits on the general purpose lanes, since diversion of trucks to truck-only lanes would reduce congestion and truck-auto interaction on the general purpose lanes. This metric is typically evaluated in terms of percent reduction in total accidents (fatal acci- dents, if total accidents were not reported) on the general purpose lanes. Reduction in emissions due to improved travel speeds on the general purpose and truck-only lanes would be another important public benefit of implementing truck-only lanes. The capac- ity enhancement along a corridor due to the implementation of truck-only lanes would result in improved travel speeds for autos and trucks on the general purpose lanes, as well as for trucks using the truck-only lanes. This improvement in travel speeds is expected to directly contribute to a net reduction in emissions along the corridor. However, the B-C analysis conducted in this study did not include environmental benefits (reduced emissions) as a public benefit category, primarily because of the lack of data required to accurately estimate travel speeds on general pur- pose and truck-only lanes. Also, the capacity enhancement due to the implementation of truck- only lanes is expected to result in some induced traffic along the corridor, as well as the displacement of auto and truck traffic from other corridors. This resulting increase in total VMT along the corridor would offset some of the emissions reduction from improved travel speeds. However, without the availability of a travel demand model, the net impact of increased VMT and improved travel speeds on emissions could not be assessed as part of the current study. Also,

62 Separation of Vehicles—CMV-Only Lanes the analysis did not consider the negative environmental impacts of CMV-only lanes such as the noise impacts of concentrated truck traffic, due to inadequate information and methods for monetizing noise impacts (also, none of the available studies provided any data that could be used to support this analysis). 4.2.2 Private-Sector Benefits Private-sector benefits could include the following: • Productivity benefits including productivity enhancements realized by trucks using the truck-only lanes, as a result of increased speeds as well as increased payloads in the case of LCV operations. • Travel time savings and reliability benefits for trucks such that trucks diverting to truck-only lanes from the general purpose lanes will experience significant improvements in performance associated with improved travel speeds (travel time savings) and reliability benefits due to reduction in accidents as a result of more stable traffic flows and homogeneity of traffic on the truck-only lanes. Since the travel time savings benefits for trucks on the truck-only lanes are captured under the productivity benefits (due to increased speeds) above, these savings are not included under the travel time savings performance measure (to avoid double-counting benefits). Trucks choosing to remain on the general purpose lanes (i.e., trucks not diverting to the truck-only lanes) will have travel time savings and reliability benefits (due to conges- tion reduction on the general purpose lanes), which are included in the travel time savings and reliability performance measures. 4.3. Data Inputs for Monetization of Performance Metrics In order to compare benefits across benefit categories and to costs, the performance metrics had to be converted to a consistent unit of valuation. This involved monetizing the performance benefits to equivalent dollar values. In order to monetize benefits, the default factors in Table 4.1 were used. The values presented in Table 4.1 are for 2008 dollars (in the NPV analysis, these fac- Monetization Factor Default Value Source Truck Value of Time ($ per Hour)1 39 Average value (indexed to 2008) for heavy-heavy duty trucks (HHDT) derived from various sources (refer to Table C.1 in Appendix C) Auto Value of Time ($ per Hour) 10 Average value (indexed to 2008) based on the assumption that auto value of time is approximately 50% of average wage rate Fatality Accidents ($ per Accident) 4,365,164 FHWA2 Injury Accidents ($ per Accident) 131,642 FHWA2 Property-Damage-Only Accidents ($ per Accident) 8,226 FHWA2 Notes: 1. The auto and truck value of time estimates presented in the table are used to monetize travel time savings. For monetizing travel time reliability benefits (measured in terms of savings in incident-related delay), these estimates are adjusted by a factor of 1.5. 2. Federal Highway Administration, Crash Cost Estimates by Maximum Police-Reported Injury Severity Within Selected Crash Geometries, Publication No. FHWA-HRT-05-051, October 2005. Table 4.1. Default values for benefits monetization factors, indexed for 2008.

Benefit-Cost Analysis 63 tors are adjusted for inflation for the future years using average rate of inflation of 3% derived from historic growth in the consumer price index [CPI]). 4.4 Unit Cost Data Table 4.2 provides unit cost estimates associated with the implementation of truck-only lane and mixed-flow lane facilities. The unit costs in Table 4.2 include capital costs associated with right-of-way acquisition and construction costs (including lanes, interchanges, and staging areas in the case of LCV operations). Since the costs may also vary depending on the type of corridor (long-haul versus urban), the cost information is presented separately for the two corridor sce- narios. O&M costs are estimated based on the assumptions in the Georgia Statewide Truck Lane Needs Identification Study, which assumes O&M costs for truck-only toll lane corridors to be 0.5% of total project capital costs in the base year, which increase each year at a 3% rate of inflation (based on historic growth in CPI). 4.5 Economic Assumptions for Net Present Value Analysis For the purpose of the B-C analysis, it is assumed that the corridor is operational beginning in 2008, and benefits are accrued for a study time horizon up to 2030. The discount rate is assumed to be 7%, as recommended by the Office of Management and Budget (OMB) for proj- ects providing societal benefits. Average annual growth rate in truck and auto traffic for the NPV analysis is assumed to be 3.3% and 1.8%, respectively, based on truck and auto VMT growth esti- mates from FHWA’s Freight Analysis Framework (FAF).44 Annual rate of inflation for truck freight rates and operating costs (which are used as inputs in the calculation of truck productiv- ity benefits) is assumed to be 3% based on historic trends in the CPI. Key assumptions used in the NPV analysis are summarized as follows for annual changes from 2008 to 2030: • Growth rate for autos—1.8% (based on FHWA FAF VMT growth estimates), • Growth rate for trucks—3.3% (based on FHWA FAF VMT growth estimates), • Rate of inflation—3.0% (based on historic trends in CPI), and • Discount rate—7.0% (based on OMB recommendations). 4.6 Corridor Descriptions and Corridor-Specific Benefit-Cost Methodologies 4.6.1 Long-Haul Corridors Long-haul corridors can experience a wide range of traffic conditions. Unlike urban corridor scenarios where truck-only lanes are generally part of a strategy to meet capacity improvement needs (in cases where truck traffic has a disproportionate impact on corridor congestion), the rationale for truck-only lanes along long-haul corridors can sometimes be to address congestion moving in, out, or around metropolitan areas, to increase truck productivity in low-volume rural corridors, or to achieve freight efficiency and reduce costs to businesses. Examples of long-haul corridor rationales other than to address congestion include the following: • Need to operate LCVs to enhance trucking productivity along long-haul corridors. Oper- ating LCVs on general purpose lanes is known to have safety issues due to interactions of LCVs with passenger vehicles; 44See http://www.ops.fhwa.dot.gov/freight/presentations/lambert_nasto.htm, Slide 7.

64 Separation of Vehicles—CMV-Only Lanes Corridor Scenario Cost Category Alternative Value Source Mixed-flow lane 2.8 Middleton, D., S. Venglar, C. Quiroga, D. Lord, and D. Jasek, Strategies for Separating Trucks from Passenger Vehicles: Final Report, Texas Transportation Institute (TTI), September 2006. Construction costs—lanes ($ million per lane mile) Truck-only lane 5.5 Middleton, D., S. Venglar, C. Quiroga, D. Lord, and D. Jasek, Strategies for Separating Trucks from Passenger Vehicles: Final Report, Texas Transportation Institute (TTI), September 2006. Mixed-flow lane 80 Cambridge Systematics (assumption based on Highway Economic Requirements System [HERS] base case value) Construction costs— interchange ($ million per interchange) Truck-only lane 80 HERS Mixed-flow lane 1.2 Woudsma, C., T. Litman, and G. Weisbrod, A Report on the Estimation of Unit Values of Land Occupied by Transportation Infrastructures in Canada, Transport Canada, 2006. Urban Corridors Right-of-way (ROW) acquisition costs ($ million per lane mile) Truck-only lane 1.2 Woudsma, C., T. Litman, and G. Weisbrod, A Report on the Estimation of Unit Values of Land Occupied by Transportation Infrastructures in Canada, Transport Canada, 2006. Mixed-flow lane 2.8 Middleton, D., S. Venglar, C. Quiroga, D. Lord, and D. Jasek, Strategies for Separating Trucks from Passenger Vehicles: Final Report, Texas Transportation Institute (TTI), September 2006. Truck-only lane— without LCV 5.5 Middleton, D., S. Venglar, C. Quiroga, D. Lord, and D. Jasek, Strategies for Separating Trucks from Passenger Vehicles: Final Report, Texas Transportation Institute (TTI), September 2006. Construction costs—lanes ($ million per lane mile) Truck-only lane— with LCV 5.9 Incremental costs due to LCV operations derived from data presented in the Western Uniformity Scenario Analysis Mixed-flow lane 80 Cambridge Systematics (assumption based on HERS base case value) Truck-only lane— without LCV 80 HERS Construction costs— interchange ($ million per interchange) Truck-only lane— with LCV 86 Incremental costs due to LCV operations derived from data presented in the Western Uniformity Scenario Analysis Mixed-flow lane N/A N/A Truck-only lane— without LCV N/A N/A Long-Haul Corridors Construction costs— staging areas ($ million per staging facility) Truck-only lane— with LCV (staging area in rural location) 2.8 U.S.DOT’s Comprehensive Truck Size and Weight Study, http://www.fhwa.dot.gov/reports/tswstudy/tswfinal. htm. Truck-only lane— with LCV (staging area in urban location) 4.5 U.S.DOT’s Comprehensive Truck Size and Weight Study, http://www.fhwa.dot.gov/reports/tswstudy/tswfinal. htm. Table 4.2. Unit costs for truck-only and mixed-flow lane facilities.

Benefit-Cost Analysis 65 • Need to meet truck oversize/overweight (OS/OW) requirements. Operating OS/OW trucks on general purpose lanes is known to have safety issues, and is expected to have a detrimental impact on pavements; and • Need to separate trucks from autos along corridors. Terrain and other system configura- tional issues may be leading to safety problems due to truck-auto operational conflicts. Based on these observations, the representative baseline scenario for long-haul corridors assumes modest overall traffic volumes (some congestion) with high levels of truck traffic. Both average daily total and truck traffic volumes grow over the forecast period, but truck traffic grows at a faster rate. To evaluate the travel time benefits of truck-only lanes, in addition to a no-build alter- native, an alternative with additional general purpose lanes has been considered in the analysis. In addition to analyzing congestion reduction benefits (in terms of travel time savings), a major feature of the analysis involves examining the benefits and costs of LCV operations on the truck- only lanes (OS/OW truck operations were not considered as part of the current analysis since there was a limited body of research available to provide inputs to allow for a robust assessment of the performance benefits of truck-only lanes with OS/OW truck operations). Considering the increased interest of states to allow special permit OS/OW truck operations based on permit fees, however, the performance and feasibility of these operations on truck-only lanes would be an important issue to consider as part of future research on truck-only lanes. Generic Corridor Characteristics The characteristics of the generic baseline corridor for the B-C analysis of truck-only lanes along long-haul corridors were derived from the characteristics of the long-haul corridors analyzed in the Reason Foundation study45 for the selection of pilot corridors for the implementation of toll truckways. Table 4.3 summarizes these characteristics for the base year (2008). 45R. W. Poole, Jr. and P. Samuel, Policy Study 316: Corridors for Toll Truckways: Suggested Locations for Pilot Projects, Reason Foundation, February 2004. Corridor Scenario Cost Category Alternative Value Source Mixed-flow lane 0.1 Trans-Texas Corridor (TTC) cost assumptions and Washington State Department of Transportation, Washington Commerce Corridor Feasibility Study, December 2004, http://www.wsdot.wa.gov/NR/rdonlyres/5A1D7325 -AFAF-4BD1-9336- BECCDEE92ADF/0/WCC_FinalReport.pdf.. Truck-only lane— without LCV 0.1 Trans-Texas Corridor (TTC) cost assumptions and Washington State Department of Transportation, Washington Commerce Corridor Feasibility Study, December 2004, http://www.wsdot.wa.gov/NR/rdonlyres/5A1D7325 -AFAF-4BD1-9336- BECCDEE92ADF/0/WCC_FinalReport.pdf. ROW acquisition costs ($ million per lane mile) Truck-only lane— with LCV 0.1 Trans-Texas Corridor (TTC) cost assumptions, and Washington State Department of Transportation, Washington Commerce Corridor Feasibility Study, December 2004, http://www.wsdot.wa.gov/NR/rdonlyres/5A1D7325 -AFAF-4BD1-9336- BECCDEE92ADF/0/WCC_FinalReport.pdf. Table 4.2. (Continued).

66 Separation of Vehicles—CMV-Only Lanes For the baseline analysis, assumptions were needed for the level of usage of the truck-only lanes (otherwise termed truck diversion to truck-only lanes). This information is used to deter- mine V/C ratios, speeds, and travel time benefits. However, the results of the benefits analysis suggest that the level of diversion is critical to the potential success of truck-only lanes, particu- larly when LCV operations are involved. In the case of truck-only lanes without LCV operations, truck lane usage largely will be a function of the difference in speeds between the mixed-flow lanes and the truck-only lanes and the availability of access points. Generally, this can be deter- mined using standard travel demand models and commodity flow and truck O-D data. In the case of truck-only lanes with LCV operations, a more comprehensive analysis of markets that take into account the O-D patterns of the trucks, the types of commodities carried, locations of staging areas, and business characteristics of the motor carriers is required to accurately deter- mine the diversion from standard trucks to LCVs. None of the studies reviewed for this project included this type of market analysis. These studies arbitrarily hypothesized ranges of utilization that tended to be fairly high (40% or more). The I-15 Comprehensive Corridor Study in South- ern California and recent work for FHWA have made high-level estimates of diversion to LCV lanes based on data on commodities typically carried in LCVs on the existing LCV network, O-D patterns of trucks relative to the existing LCV network, and configurations that might switch to LCV operations. These estimates suggest that diversion markets might be substantially smaller than the ranges represented in the studies reviewed for this project. Therefore, a wider range of diversion rates was examined in this project as part of a sensitivity analysis approach. Description of Alternatives In addition to the baseline no-build corridor, three build alternatives were developed for the B-C analysis of long-haul corridors, which included the following: • Additional mixed-flow lanes. Although long-haul intercity corridors generally do not have high levels of congestion, in certain high-potential corridors, particularly in the industrial midwestern United States and along the U.S. coasts in certain key corridors, there are high lev- els of congestion around cities and sufficient volumes that over the time horizon of the analy- sis, congestion levels are expected to grow. Thus, the evaluation of travel time benefits would tend to favor truck-only lane solutions if they are only compared with no-build conditions, because the truck-only lanes have more capacity. In many of the studies used in the perfor- mance evaluations presented in the previous chapter, this was a shortcoming since they only compared truck-only lanes with a no-build alternative (without considering an additional mixed-flow lane alternative). Therefore, in the generic corridor analysis, a build alternative was defined that included additional mixed-flow lanes. In the long-haul corridor, this alternative Parameter Value Rationale Length of Corridor 400 mi Long-haul corridors considered in the Reason Foundation study ranged in length from 15 to 973 mi and the average length was estimated to be 400 mi Number of Lanes 6 Corridors ranged in number of lanes between 4 and 7 lanes and average was estimated to be 6 lanes Average Daily Total Traffic 105,000 Corridors ranged between 57,000 and 196,000 average daily traffic (ADT) and average was estimated to be 105,000 Average Daily Truck Traffic 14,000 Corridors ranged between 6,000 and 20,000 average daily truck traffic (ADTT) and average was estimated to be 14,000 Truck Share of Total Traffic 13.3% Table 4.3. Generic baseline long-haul corridor characteristics.

Benefit-Cost Analysis 67 includes two additional mixed-flow lanes in each direction along the entire length (400 mi) of the corridor. • Truck-only lanes without LCV operations. This alternative is comprised of two truck lanes in each direction along the entire length (400 mi) of the corridor. This alternative was included to analyze the performance benefits and relative costs of truck lanes (without LCV operations) in comparison with additional mixed-flow lanes. • Truck-only lanes with LCV operations. As discussed earlier, many long-haul corridor con- cepts are focused on improving freight operations through productivity improvements while at the same time gaining the operational and safety benefits of truck-auto separation. There- fore, this generic corridor analysis includes an alternative with LCV operations. This alterna- tive is comprised of two truck lanes in each direction along the entire length of the corridor, and these truck lanes allow LCV operations. Calculation of Benefits Net present value of productivity benefits. For the purposes of this study, the calculation of productivity benefits follows the methods used by the Reason Foundation analysis of LCV oper- ations. This approach calculates productivity benefits as a private-sector benefit that only accrues to users of the truck-only lanes (both cases, with and without LCVs). The approach is based on the estimation of the net increase in trucking industry earnings due to operations on truck-only lanes and derives from both reduced travel times (which create the opportunity to carry more loads and achieve higher equipment utilization) and the ability to carry higher payloads per unit operating costs. The specific assumptions and approaches used are described in more detail in Appendix C, along with the results of the NPV calculation of these benefits. Net present value of travel time savings for mixed-flow traffic. Travel time savings benefits are quantified for each of the years (2008 to 2030) for each of the build alternatives relative to the no-build alternative, to estimate the total NPV of travel time savings for the B-C analysis. Note that these estimates only include the total travel time savings for mixed-flow traffic (autos and trucks on the general purpose lanes). As discussed earlier, for the truck-only lane alterna- tives, travel time savings for trucks on the truck-only lanes are not included in this performance measure since these benefits are captured in the productivity benefits calculations. A more detailed description of the calculation methodology is presented in Appendix C, along with complete results of the calculations. Net present value of safety benefits. Safety benefits are quantified in terms of the NPV of mon- etary savings in total accidents (fatality, injury, and property-damage only [PDO]) for the 2008 to 2030 time period for each of the build alternatives compared to the no-build alternative. Total accidents for each of the alternatives are estimated using inputs on auto and truck VMTs, level of congestion (V/C) on the general purpose and truck lanes, and accident rates (for fatality, injury, and PDO accidents in terms of accidents per million VMT) as a function of V/C from the IDAS User Manual.46 Additionally, as discussed in the performance evaluation task, for the truck lane alternatives, the total accidents on the general purpose lanes estimated using IDAS inputs are reduced by a factor of 15%, as recommended by the Douglas handbook47 to account for the safety benefits of truck-auto separation. A more detailed discussion of the calculation methodology and results of the NPV calculation are presented in Appendix C. 4.6.2 Urban Corridors The B-C analysis approach for urban corridors compares the relative benefits and costs of truck-only lanes with additional mixed-flow lanes, based on a generic corridor analysis approach, 46See http://idas.camsys.com/userManual/App_b.pdf. 47J. G. Douglas, Handbook for Planning Truck Facilities on Urban Highways, August 2004.

68 Separation of Vehicles—CMV-Only Lanes similar to the one described in the previous section for long-haul corridors. Urban corridors with high auto and truck traffic volumes would be primary candidates requiring such a comparative assessment, since congestion, reliability, and safety are expected to be key issues along such cor- ridors, and adding capacity not only to mitigate congestion, but also to improve reliability and safety would be a primary need. It would be important to analyze if adding capacity while at the same time achieving truck-auto separation (through truck-only lanes) would be more cost effec- tive along these corridors compared to adding mixed-flow capacity. A key consideration in analyzing the differential capacity benefits of truck lanes as com- pared to mixed-flow lanes is the difference in the time-of-day characteristics of truck traffic and auto traffic. Auto volumes tend to peak during the morning and evening commuter hours whereas truck volumes tend to peak in the middle of the day. The benefits of truck- only lanes will therefore depend largely on the degree to which congestion extends through- out the day, truck and auto peaks overlap, and truck volumes are high enough to achieve high levels of truck lane use. Unfortunately, the study team was unable to account for time-of-day variations between trucks and autos in the B-C analysis because of the lack of a travel demand model or a simulation tool to assess the time-of-day variations between trucks and autos. However, future analyses to assess the performance benefits of truck-only lanes should consider time-of-day variations between trucks and autos through the use of travel demand models and/or simulation tools to conduct an accurate assessment of the true performance benefits of truck-only lanes. Since none of the reviewed studies under the urban corridor scenario provide B-C analysis results based on a one-to-one comparison between truck-only lanes and additional mixed-flow lanes, the B-C assessment presented in this section is based on comparing truck-only lanes and mixed-flow lane alternatives that add the same amount of capacity. The benefits included in the B-C analysis include travel time savings, reliability, and safety. Generic Corridor Characteristics The I-710 corridor in Southern California serves as a prime example of a corridor in an urban area with configurational, demand, and operational characteristics that are suitable for the com- parative assessment of the relative benefits and costs of truck-only lanes and additional mixed- flow lanes. Some of these characteristics include the following: • Location (impacts corridor demand characteristics): – Access to major freight facilities. Primary access route to major seaports, thereby resulting in high truck (port-related) volumes on the corridor; and – Primary urban area corridor with high auto and truck (port as well as domestic truck) traf- fic volumes. • Safety: – High accident rates due to congestion in the peak periods, as well as high level of truck-auto interactions. • Reliability: – Due to congestion and high truck-auto interactions (and associated incident-related issues) and high port truck traffic volumes, improving reliability is not only important for autos, but also for the international goods movement supply chains whose efficiency is affected by reliability issues along the corridor. Consequently, the characteristics of the urban area generic corridor for the B-C analysis, including the length, auto and truck volumes, and number of lanes, draw heavily from analysis of the I-710 corridor. The B-C analysis approach involves conducting sensitivity analyses to pro- vide a basis for drawing conclusions from a wide range of critical urban corridor characteristics and addressing uncertainty in estimates of some of the cost and benefit parameters.

Benefit-Cost Analysis 69 The demand and configurational characteristics of the generic urban corridor are defined as follows: • Length = 20 mi, • Number of lanes (bidirectional) under the no-build alternative = 10, • Daily auto volume = 200,000, • Daily truck volume = 60,000, • Daily total traffic volume = 260,000, and • Truck share of total traffic = 23%. Description of Alternatives To ensure consistency in the comparisons of relative benefits and costs between the build alternatives (additional mixed-flow and truck-only lanes), it is assumed that these alternatives provide similar levels of additional capacity along the corridor. The characteristics of these alter- natives are as follows: • Additional mixed-flow lanes. This alternative includes two additional mixed-flow lanes in each direction over the entire stretch of the corridor; and • Truck-only lanes. This alternative includes two truck-only lanes in each direction over the entire stretch of the corridor. The assumptions related to data inputs (study time period, auto and truck volume growth rates, inflation rate, and discount rate) for the NPV analysis of various benefits components have been discussed in Section 4.5. The following sections discuss the performance measures estimated. Calculation of Benefits NPV of travel time savings. The estimation of the NPV of travel time savings associated with the build alternatives (additional mixed-flow lanes and truck-only lanes) relative to the no-build alternative was based on estimating average daily V/C and associated speeds on general purpose lanes and truck-only lanes given the assumptions about utilization of the truck lanes. Since this corridor scenario does not consider productivity benefits, for the truck-only lane alternative the travel time savings for trucks diverting to the truck lanes are included in the total travel time sav- ings benefits. The estimates do not take into account time-of-day variation in traffic volumes for autos and trucks. A complete description of the methodology and the results of the calculations are presented in Appendix C. NPV of reliability benefits. Reliability benefits are quantified in terms of the monetized savings in incident-related delay. Techniques and specific performance metrics for predict- ing and measuring reliability are still very much under development. One approach to assess- ing the value of reliability benefits has been to assume that the value of time for incident-related delays is significantly higher than that of recurrent delay because incident-related delay is inherently unpredictable. For trucking, it is possible to plan for recurrent delay and to incor- porate these plans into cost structures, whereas unplanned incidents can have highly variable (and sometimes very significant) cost implications. Appendix C presents a more detailed review of the approach used to monetize reliability benefits and provides references to the supporting studies justifying this approach. In this project, incident-related delay was calcu- lated using incident-delay rates (delay per vehicle mile) from IDAS as a function of V/C and configuration of the highway and was valued at 1.5 times the recurrent delay VOT (value of time) estimates to arrive at the value of incident-related delay for the monetization of relia- bility benefits. For the truck-only lane alternative, the incident-related delays are reduced by an additional factor of 15%, to account for the reduction in incidents due to truck-auto separation.

70 Separation of Vehicles—CMV-Only Lanes NPV of safety benefits. The estimation of NPV of safety benefits associated with the build alternatives was developed by calculating accident rates per million VMT as a function of V/C using look-up factors from the previously mentioned IDAS handbook. These were further reduced by 15% for the truck-only lanes to account for the benefits of truck-auto separations based on the results of previously cited research by Douglas. A more complete description of this approach is included in Appendix C. 4.7 Results of the Benefit-Cost Analysis 4.7.1 Long-Haul Corridor In order to develop the B-C analysis of a generic corridor, a number of assumptions about key variables needed to be made. In analysis of an actual corridor, these need not be assumptions but could be based on market analysis of actual conditions. Further, without taking into considera- tion actual corridor conditions, the need for interchanges, and the need for supporting infra- structure (like staging areas), cost estimates for the long-haul corridor alternatives could vary widely from the assumptions used in the generic corridor analysis. Costs This section presents the comparative costs for all cost components of each alternative. The cost estimates are developed using the unit costs presented in an earlier section, and the config- urational and travel demand characteristics along the generic corridor. Since there is inadequate information on some of the truck-only lane cost components such as O&M costs and LCV equipment costs, the B-C analysis uses a range of costs. The range of costs was developed by first estimating a baseline total cost for each alternative, and varying the costs across the baseline (lower and upper limit costs with the baseline as the mean) using a variance of ±20% relative to the baseline. Table 4.4 presents the baseline cost components for each of the alternatives. A detailed discus- sion of the approach to calculating costs and their relationship to the NPV analysis is presented in Appendix C. As mentioned previously, to account for the uncertainty in costs in the sensitivity analysis, the total costs for each alternative in Table 4.4 are varied to arrive at a representative range of cost estimates for the B-C analysis. Table 4.5 presents these cost variations for the long-haul corridor alternatives. Truck-Only Lanes Costs Additional Mixed-Flow Lanes Without LCV Operations With LCV Operations ROW Acquisition 0.2 0.2 0.2 Construction (Lanes) 4.5 8.8 9.4 Construction (Interchanges) 0.7 0.7 0.8 Construction (Staging Areas—Rural Locations) – – 0.003 Construction (Staging Areas—Urban Locations) – – 0.009 O&M 0.4 0.8 0.8 Total 5.8 10.5 11.2 Table 4.4. Baseline cost components for long-haul corridor alternatives, in billions of dollars (indexed to 2008).

Benefit-Cost Analysis 71 Monetized Benefits As mentioned, a range of diversion rates is considered in the B-C analysis to assess the impact of diversion rates on the performance benefits of truck-only lanes and to identify the range of diversion rates for which truck-only lanes are observed to be cost-effective compared to adding mixed-flow capacity. The results for the monetized benefits under each performance measure for each alternative under different diversion rate assumptions are presented in Table 4.6. Note that the results for the additional mixed-flow lane alternative do not change under different diversion rate scenarios because they are only applicable to the truck-only lane alternative. Benefit-Cost Results Figure 4.1 shows the comparison of B-C results for each alternative as a function of diversion rates. Conclusions The following are key conclusions from the B-C analysis of truck-only lanes in the long-haul generic corridor: • The results suggest that high levels of diversion would be needed for truck-only lanes to be judged a preferred alternative both in terms of getting to a B-C ratio greater than 1.0 and exceeding the B-C ratio of adding more general purpose lanes. • In the case of truck-only lanes without LCV operations, even under the most optimistic scenario favoring this alternative (i.e., truck-only lane costs being closer to the lower threshold—20% below the baseline; and additional mixed-flow lane costs falling in the upper threshold—20% above the baseline), a minimum of 50% diversion would be required before the truck-only lanes become more cost-effective compared to adding mixed-flow capacity. Under the applicability Alternative Lower Limit for Cost (20% Below Baseline) Baseline Cost Upper Limit for Cost (20% Above Baseline) Additional Mixed-Flow Lanes 4.7 5.8 7.0 Truck-Only Lanes without LCV Operations 8.4 10.5 12.6 Truck-Only Lanes with LCV Operations 9.0 11.2 13.5 Table 4.5. Range of costs considered for the B-C analysis, in billions of dollars (indexed to 2008). Additional Mixed-Flow Lanes Truck-Only Lanes without LCVs Truck-Only Lanes with LCVs Diversion Rate (%) Productivity Travel Time Safety Total Productivity Travel Time Safety Total Productivity Travel Time Safety Total 10 – 4.9 – 4.9 0.6 0.6 0.1 1.4 1.3 0.6 0.3 2.2 20 – 4.9 – 4.9 1.2 1.1 0.3 2.6 2.6 1.1 0.5 4.2 30 – 4.9 – 4.9 1.8 1.6 0.4 3.8 3.8 1.6 0.8 6.2 40 – 4.9 – 4.9 2.4 1.9 0.5 4.9 5.1 1.9 1.1 8.1 50 – 4.9 – 4.9 3.0 2.2 0.7 5.9 6.4 2.2 1.3 9.9 60 – 4.9 – 4.9 3.6 2.4 0.8 6.8 7.7 2.4 1.6 11.7 70 – 4.9 – 4.9 4.2 2.6 0.9 7.7 9.0 2.6 1.8 13.3 80 – 4.9 – 4.9 4.8 2.7 1.0 8.5 10.2 2.7 2.0 15.0 90 – 4.9 – 4.9 5.4 2.8 1.1 9.2 11.5 2.8 2.3 16.5 100 – 4.9 – 4.9 5.9 2.8 1.2 9.9 12.8 2.8 2.5 18.0 Table 4.6. Monetized benefits of alternatives for different diversion rate assumptions, in millions of dollars (indexed to 2008).

72 Separation of Vehicles—CMV-Only Lanes of baseline conditions, the diversion rates would need to be very high (more than 85%) before this alternative performs better in terms of cost-effectiveness compared to adding mixed-flow lanes. Given this high level of diversion, which might not be achievable along long-haul cor- ridors, particularly those with relatively lower levels of congestion, truck-only lanes without LCV operations would generally appear to be an inappropriate choice under the general con- ditions described for long-haul corridors. • In the case of LCV operations on truck-only lanes, even under the most optimistic scenario favoring this alternative (i.e., lower end of the costs for truck-only lanes and upper end of the costs for mixed-flow lanes), a minimum of 30% diversion would be required before the truck- only lane alternative becomes more cost-effective compared to adding mixed-flow capacity. Under the applicability of baseline conditions, the diversion rate would need to be at least 50% before truck-only lanes with LCV operations perform better compared to mixed-flow lanes. Also, diversion to the LCVs would need to be in the range of 45% to 70% (depending on costs) to achieve B-C ratios greater than 1.0. • Based on the results, it appears that for long-haul corridors, the decision making for corridor investment options would primarily be governed by the relative B-C performance of truck- only lanes with LCV operations compared to additional mixed-flow lanes. If the market for LCVs is not present along a corridor or is such that it would only result in lower diversion rates (less than 30% based on Figure 4.1) based on the type of commodities, connectivity of the cor- ridor to the larger LCV network, and/or truck O-D patterns, it would clearly rule out the appli- cability of truck-only lanes along the corridor (given that typical conditions along long-haul corridors would make truck-only lanes without LCVs not a preferred alternative compared to adding mixed-flow lanes). Based on the market conditions, which would govern the potential rate of diversion, the results from Figure 4.1 could be applied to assess the cost-effectiveness of implementing truck-only lanes with LCV operations compared to adding mixed-flow capacity along a corridor. • As mentioned earlier, the results in Figure 4.1 are generated based on the defined characteris- tics of the representative baseline corridor. Consequently, these trends are expected to change - 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 10% 30%20% 40% 50% 60% 70% 80% 90% 100% Diversion Rate B/ C Mixed Flow Upper B/C Limit Mixed Flow Baseline B/C Mixed Flow Lower B/C Limit Truck Lane (w/o LCV) Upper B/C Limit Truck lane (w/o LCV) Baseline B/C Truck Lane (w/o LCV) Lower B/C Limit Truck Lane (w/ LCV) Upper B/C Limit Truck Lane (w/ LCV) Baseline B/C Truck Lane (w/ LCV) Lower B/C Limit Figure 4.1. B-C ratios for alternatives as a function of diversion rate.

Benefit-Cost Analysis 73 based on changes in corridor congestion characteristics, which are not reflected in the results. It is expected that these changes will be more pronounced for the mixed-flow lane and truck- only lane without LCV alternatives (compared to the truck-only lane with LCV operation alternatives) because a relatively large share of the benefits for these alternatives is associated with travel time savings (while productivity benefits from LCV operations account for a large share of the benefits for this alternative). This would mean that the relative difference in per- formance of mixed-flow lanes and truck-only lanes without LCV operations might not change much with a decrease in congestion levels (compared to the conditions defined in this analy- sis), but the relative performance of the truck-only lane alternative with LCV operations com- pared to the mixed-flow lane alternative is expected to improve. In other words, decrease in corridor congestion levels would potentially bring the minimum diversion threshold for cost- effectiveness of the truck-only lane alternative to lower than 30%. • As noted in the introduction to this chapter, the results in Figure 4.1 very likely underestimate the benefits of truck-only lanes because they do not fully account for the safety benefits of truck-only lanes as compared with additional mixed-flow lanes. This shortcoming is unlikely to significantly alter the conclusions since safety benefits are a relatively small contributor to overall benefits. • The analysis does not take into account potential market diversion from congested rail corri- dors to the LCV lanes, which could add further benefits without any increase in costs, partic- ularly in cases where LCV lanes provide significant improvements in reliability, speed, and productivity, leading to diversion from rail to LCVs. Market diversion from rail to LCV cor- ridors was not taken into consideration because this type of analysis is typically corridor spe- cific, and would require extensive market analysis to assess the types of commodities along the corridor being studied, commodity O-D patterns, and shipper surveys to assess the propen- sity for cargo diversion from rail to LCVs, which was beyond the scope of this study. How- ever, it would be critical to account for modal diversion in the feasibility analysis of CMV-only lanes (with LCV operations) along long-haul corridors as part of future research (it is antici- pated that the consideration of truck-rail diversion typically would be based on a case-by-case basis, depending on the conditions along specific long-haul corridors being studied for the feasibility of implementing CMV-only lanes). 4.7.2 Urban Corridor As in the case of the long-haul corridor scenario, the B-C analysis to evaluate the cost- effectiveness of truck-only lanes compared to adding mixed-flow capacity on urban corridors was based on a sensitivity analysis approach that involved analyzing the variations in B-C ratios for the truck-only lane alternative as a function of diversion rate, and comparing these results with the benefit-cost for the additional mixed-flow lane alternative to identify the range of diversion rates for which truck-only lanes are observed to be cost-effective when compared to adding mixed-flow capacity. The following sections present the costs, monetized benefits, and compar- isons of benefit-cost between the urban corridor alternatives for various diversion rate scenarios. Costs This section quantifies the various cost components associated with implementing the build alternatives for the purpose of conducting a comparative B-C analysis, using the unit cost esti- mates presented in an earlier section, and the configurational characteristics of the urban generic corridor. As with the long-haul corridors scenario, due to uncertainties in costs associated with implementing truck-only lanes, which could be impacted by corridor (such as number of inter- changes) as well as demand characteristics (which would potentially impact O&M costs), the B-C analysis uses a range of costs as part of the sensitivity analysis. The range of costs was devel- oped by first estimating a baseline total cost for each alternative, and varying the costs across the

74 Separation of Vehicles—CMV-Only Lanes baseline (lower and upper limit costs with the baseline as the mean), using a variance of ±20% relative to the baseline. Table 4.7 presents the baseline cost components for the urban corridor alternatives. A detailed discussion of the approach to calculating costs and their relationship to the NPV analysis is pre- sented in Appendix C. Similar to the B-C analysis for long-haul corridors, to account for the uncertainty in costs in the sensitivity analysis, the total costs for each alternative are varied to arrive at a representative range of cost estimates for the B-C analysis. Table 4.8 presents these cost variations for the urban corridor alternatives. Monetized Benefits As in the long-haul corridor scenario, a range of diversion rates is considered in the B-C analy- sis to assess the impact of diversion rates on the performance benefits of truck-only lanes and identify the range of diversion rates for which truck-only lanes are observed to be cost-effective when compared to adding mixed-flow capacity along urban corridors. The results for the mon- etized benefits under each performance measure for each alternative under different diversion rate assumptions are presented in Table 4.9. Note that the results for the additional mixed-flow lane alternative do not change under different diversion rate scenarios because they are only applicable to the truck-only lane alternative. Benefit-Cost Results Figure 4.2 shows the comparison of B-C results for each alternative as a function of diversion rates. Conclusions Following are some of the caveats associated with the current analysis, which are important to note before discussing the key conclusions from the results in Figure 4.2: • The B-C ratios from the NPV analysis for the mixed-flow and truck-only lane alternatives are observed to be significantly high, and should be viewed with caution. Since the B-C results are Costs Mixed-Flow Lanes Truck-Only Lanes (without LCV Operations) ROW Acquisition 0.1 0.1 Construction (Lanes) 0.2 0.4 Construction (Interchanges) 0.4 0.4 O&M 0.1 0.1 Total 0.8 1.0 Table 4.7. Baseline cost components for urban corridor alternatives, in billions of dollars (indexed to 2008). Alternative Lower Limit for Cost (20% Below Baseline) Baseline Cost Upper Limit for Cost (20% Above Baseline) Mixed-Flow Lanes 0.6 0.8 1.0 Truck-Only Lanes 0.8 1.0 1.2 Table 4.8. Range of costs considered for the B-C analysis, in billions of dollars (indexed to 2008).

Benefit-Cost Analysis 75 a function of a range of factors, including the demand and configurational characteristics of the representative baseline corridor (as mentioned earlier, the defined conditions along the base- line generic corridor may not be fully representative of conditions along an actual corridor, which may have an impact on B-C results), the time horizon for the NPV analysis, the benefits monetization factors (e.g., value of time estimates) used in the analysis, and uncertainties in the costs, the B-C results in Figure 4.2 are used only to assess the relative B-C performance between the mixed-flow and truck-only lane alternatives, and are not for assessing the B-C performance of each of the build alternatives individually against the no-build alternative. • The estimation of the performance benefits of alternatives does not consider differences in time-of-day distributions between auto and truck traffic volumes, which could potentially impact the benefits of truck-only lanes, and consequently, the relative B-C performance of truck-only lanes when compared to adding mixed-flow capacity. For the interpretation of the Additional Mixed-Flow Lanes Truck-Only Lanes Diversion Rate (%) Travel Time Reliability Safety Total Travel Time Reliability Safety Total 10 5.6 1.5 0.4 7.4 1.5 0.4 0.1 2.1 20 5.6 1.5 0.4 7.4 2.8 0.9 0.3 3.9 30 5.6 1.5 0.4 7.4 3.8 1.3 0.4 5.5 40 5.6 1.5 0.4 7.4 4.6 1.7 0.5 6.8 50 5.6 1.5 0.4 7.4 5.2 1.9 0.5 7.6 60 5.6 1.5 0.4 7.4 5.5 2.0 0.6 8.1 70 5.6 1.5 0.4 7.4 5.5 2.0 0.6 8.1 80 5.6 1.5 0.4 7.4 5.1 2.1 0.6 7.7 90 5.6 1.5 0.4 7.4 4.0 2.0 0.6 6.6 100 5.6 1.5 0.4 7.4 2.1 1.9 0.6 4.6 Table 4.9. Monetized benefits of alternatives for different diversion rate assumptions, in billions of dollars. - 2.0 4.0 6.0 8.0 10.0 12.0 14.0 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Diversion Rate B/ C Mixed Flow Lower B/C Limit Mixed Flow Baseline B/C Mixed Flow Upper B/C Limit Truck only Lane Lower B/C Limit Truck only Lane Baseline B/C Truck Only Lane Upper B/C Limit Figure 4.2. B-C results for alternatives as a function of diversion rate.

76 Separation of Vehicles—CMV-Only Lanes results in Figure 4.2, it is assumed that time-of-day differences between auto and truck vol- umes for the representative baseline corridor are not significant, and therefore, would not impact the performance of truck-only lanes. • Due to a lack of robust analytical tools to assess the true safety benefits of truck-auto separa- tion (which also impacts the accuracy of the estimation of reliability benefits of truck-only lanes), the results in Figure 4.2 could be amiss in providing insights into the relative B-C per- formance of truck-only lanes when compared to adding mixed-flow capacity, particularly along corridors where safety and reliability issues caused by truck-auto interactions are a major concern. Given the above caveats, however, the results in Figure 4.2 are useful in gaining insights into the relative B-C performance of truck-only lanes when compared to additional mixed-flow lanes, which are discussed as follows: • Clearly, as observed under the long-haul corridor scenario, truck diversion rates have a direct impact on the B-C performance of truck-only lanes. Truck diversion rates of 60% to 70% pro- vide the highest B-C ratios for the truck-only lane alternative. Very high diversion rates (greater than 80%) impact overall performance under this alternative as the truck-only lanes begin to experience congestion and the system does not have optimal capacity utilization (both on the general purpose and truck-only lanes). Since trucks have a higher value of time when compared to autos (more than 2.5 times auto value of time in the current analysis), mobility on truck-only lanes is important for the truck-only lane alternative to achieve high levels of performance benefits in monetary terms. The importance of this result is significant in analyzing policy issues associated with the use of truck-only lanes (e.g., in this case, manda- tory use of truck-only lanes might not be a feasible policy option because it would not ensure optimal system performance). The B-C performance of the truck-only lane alternative is observed to be low under low diversion rates because there is under-utilization of truck-only lane capacity, and low levels of diversion from the general purpose lanes result in low level of congestion relief from these lanes. These relationships are important in understanding the impacts of tolls on truck-only lanes, since higher tolls can impact diversion rates, thus affect- ing the benefits of truck-only lanes as well as the revenue potential of tolls. • Comparing the B-C performance of mixed-flow and truck-only lane alternatives, the mixed- flow lane alternative is observed to generally have a better B-C performance when compared to the truck-only lane alternative under the defined conditions of the representative baseline corridor (although there is a range in the graph where the truck-only lane alternative could have a better performance given the uncertainties in the costs and the variations in the diver- sion rates). This can be explained to a certain extent from the results in Table 4.9, which indi- cate that a large share of the benefits for both the alternatives is driven by congestion reduction (travel time savings). These results suggest that for truck-only lanes to have a higher B-C performance when compared to mixed-flow lanes, in addition to travel time sav- ings, they have to provide significantly higher safety and reliability benefits (compared to mixed-flow lanes), which is not being achieved in this case. The implications of this obser- vation include the following: – As mentioned earlier, the safety and reliability benefits of truck-only lanes (associated with truck-auto separation) were estimated based on a post-processing approach, which involved application of accident reduction factors, without the use of robust analytical tools such as simulation. Consequently, the post-processing approach could potentially be underestimating the true safety and reliability benefits of truck-auto separation. Given the constraints in the current project, it would, therefore, be important to supplement these results with more detailed analyses of the safety and reliability performance of truck-only lanes to understand the magnitude of these benefits in relation to the mobility benefits of truck-only lanes.

Benefit-Cost Analysis 77 – The results do, however, provide insights into the types of corridor applications under which truck-only lanes could be expected to have a better B-C performance (relative to mixed-flow lanes) compared to the observations in Figure 4.2. For example, the results sug- gest that truck-only lanes could be more viable compared to mixed-flow lanes on corridors for which, in addition to congestion mitigation, there are specific performance improve- ment needs that could be better met by truck-auto separation than by adding mixed-flow capacity, which may include the following:  Congested urban corridors on which, because of terrain such as grades and other system configurational issues, there may be safety problems due to truck-auto operational con- flicts. Implementation of truck-only lanes along these corridors would provide signifi- cant levels of safety and reliability benefits in addition to travel time savings from diversion of trucks from the general purpose lanes.  Urban corridors serving as key access routes to major freight facilities (such as seaports) where high truck and auto volumes, in addition to causing congestion, may be leading to reliability problems for international goods movement supply chains relying on the corridor for truck shipments. Along these corridors, the implementation of truck-only lanes would not only relieve congestion on the general purpose lanes by diverting trucks, but also provide dedicated lanes for port truck traffic, resulting in improved truck freight mobility and reliability.

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TRB's National Cooperative Highway Research Program (NCHRP) and National Cooperative Freight Research Program (NCFRP) have jointly released NCHRP Report 649/NCFRP Report 3: Separation of Vehicles—CMV-Only Lanes. The report examines major issues and concepts that should be understood in developing new applications of commercial motor vehicle-only (CMV-only) lanes as a potential method for both easing congestion and reducing the number of traffic accidents on highways.

Appendices A through D for NCHRP Report 649/NCFRP Report 3 are available online as follows:

  • Appendix A: NCHRP Project 03-73 Separation of Vehicles—CMV-Only Lanes Task 7—Interim Report
  • Appendix B: Performance Evaluation
  • Appendix C: Benefits Monetization Factors and Unit Costs
  • Appendix D: Net Present Value Calculations for Benefit-Cost Analysis
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