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Conclusions and Recommendations 79 applications along key segments of major urban goods movement corridors. Efforts to obtain any performance data from this roadway were unsuccessful. There are some other limited examples of truck/auto separations providing data to assess the benefits of separating trucks and autos, and these were used to support the analysis in this study. These primarily include truck bypass lanes around interchanges and the dual-dual roadway sections of the New Jersey Turnpike that include auto-only and mixed-flow lanes. There have also been some experiments with truck lane restric- tions, such as those conducted by the North Central Texas Council of Governments (NCTCOG) in a study conducted from 2005 to 2006 that collected data on safety and travel time differences in lanes that were restricted to autos only, as compared to right-hand lanes in which trucks were restricted to travel. These experiments also provide information on approaches that might be used to collect data on operational performance of truck-only lanes in the future. Nonetheless, there continue to be some significant gaps in the data and analyses that have been conducted to date. These gaps limited the study team's ability to reach definitive conclusions on many aspects of truck- only lane performance and cost-effectiveness. This chapter will draw together the results of the analyses from the previous chapters to establish some general conclusions about truck-only lanes and to suggest particular areas of research that show reasonable prospects for providing answers to critical outstanding questions. The remainder of this chapter summarizes key conclusions regarding the applicability of truck- only lanes and configurations first in long-haul intercity corridors and then in urban corridors. This is followed by a summary of ideas for future research. The sections describing conclusions regarding applications of truck-only lanes also note where the current research and data are defi- cient with respect to the types of performance and B-C evaluations that need to be done, and pro- vide ideas for how the underlying data and analytical methods can be improved. 5.1 Truck-Only Lanes in Long-Haul Intercity Corridors The primary motivation for developing long-haul intercity truck-only lanes includes the following: Increase freight movement efficiency by increasing throughput and reducing travel times and delays for freight movement, Provide improved freight efficiency at costs that are lower than the monetized value of the benefits, Cost-effectively provide increased freight movement capacity in corridors with limited opportunities to expand rail mode or corridors without existing rail service, Provide dedicated facilities on long-haul corridors for longer combination vehicle (LCV) operations or meet truck over-size/over-weight (OS/OW) requirements, Increase safety by reducing truck-auto interactions, and Encourage economic development by drawing industries with high transport costs to the corridor. 5.1.1 Feasibility Criteria The literature sources reviewed in this study provide the basis for establishing some general cri- teria in terms of volumes of truck traffic, length of corridor, auto volumes, and congestion condi- tions along long-haul corridors to analyze the feasibility of implementing truck-only lanes. The Reason Foundation48 developed an approach to screening candidate long-haul corridors for tolled 48 R. W. Poole, Jr. and P. Samuel, Policy Study 316, Corridors for Toll Truckways: Suggested Locations for Pilot Proj- ects, Reason Foundation, February 2004.

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80 Separation of Vehicles--CMV-Only Lanes truck-only lanes and a congestion measure based on Highway Performance Monitoring System (HPMS) forecasts of truck and auto traffic in the corridors was included as one of the screening criteria. The Reason Foundation study also used a minimum truck volume threshold of 10,000 trucks per day to screen candidate corridors that would be viable (in terms of revenue generation potential) for the implementation of tolled truck-only lanes. The study reported that "a basic toll truckway probably needs between 2,000 and 4,000 trucks per day to be self-sufficient from toll revenues." Corridors were scored based on congestion considerations, so that the congestion score for each corridor was developed based on an estimate of the average daily volume capacity (V/C) ratio and fraction of the total corridor mileage with V/C greater than 1. The highest possible score was 15. Corridors with high congestion scores49 were as follows: Congestion score of 10 I-76 Pennsylvania Turnpike, I-15 Barstow--Las Vegas, I-81 Knoxville--Harrisburg, I-5 Bakersfield--Sacramento, I-94 Chicago--Minneapolis, I-85 Montgomery--Richmond, I-78 Harrisburg--New York City, and I-80 Oakland--Nevada Line. Congestion score of 9 I-75 Toledo--Tampa and I-65 Nashville--Gary. Congestion score of 8 I-10 Los Angeles--Phoenix, I-20 Dallas--Atlanta, and I-90 Cleveland--Buffalo. As indicated, the work of the Reason Foundation indicated potential corridors that might be good candidates for LCV operations based on some key feasibility criteria, which include the following: Daily truck volumes; Fraction of corridor length with daily truck volumes greater than a threshold (typically, 10,000 trucks per day); Congestion (V/C); Connectivity (whether the corridor provides connectivity to the existing national LCV net- work); and Trucking company responses (willingness of trucking companies to use LCV corridors with tolled truck-only lanes). However, there is a need for additional analysis beyond what has been done to date to confirm the benefits of LCV operations, establish concepts of operations, and establish optimum configu- rations. Some examples of work needed to analyze the feasibility of LCV operations on truck-only lanes are as follow: Gaining a better understanding of what types of commodities and trucking operations most ben- efit from LCV operations and developing better corridor-level origin-destination (O-D) infor- mation for these commodities in the priority corridors. The Reason Foundation work has approached the demand issue in terms of scenarios that assume a particular level of market pen- 49 R. W. Poole, Jr. and P. Samuel, Policy Study 316, Corridors for Toll Truckways: Suggested Locations for Pilot Projects, Reason Foundation, February 2004.

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Conclusions and Recommendations 81 etration of LCVs expressed as a percentage of some average level of truck demand on a heavily truck-trafficked rural corridor. But not every commodity and trucking operation is a candidate for LCV operations, and there is no basis for determining whether the assumed scenarios in the Reason Foundation work are at all representative of what might occur in these corridors. Analy- sis that takes into account the types of commodities hauled and the O-Ds (to reflect potential links to a multistate LCV network) might provide a better idea of potential demand levels for LCV operations. Understanding the impact of LCV operations on rail-truck mode share. In selecting LCV corri- dors, highest priority should be given to corridors that do not have rail service or that have very congested rail systems. In these cases, it is appropriate to look at the tradeoffs between adding new LCV lanes and investments in rail systems. In any event, the Reason Foundation corridors should at least be screened to see what opportunities exist to expand rail services in these corri- dors and the degree to which there are commodities moving in these corridors for which rail and trucking modes compete. In order to conduct these analyses, state DOTs will need access to good modal diversion models in order to analyze the propensity for cargo diversion between truck and rail modes. Developing concepts of operations for the high-priority LCV corridors. B-C studies need to be conducted in each corridor to determine what types of trucking configurations would be opti- mal (in terms of productivity benefits traded off against cost of design features), how to best link new LCV corridors with the existing national LCV network, the design of the optimal system of truck staging areas to provide off-network access, and regulatory/enforcement mechanisms to ensure compliance and efficiency in LCV operations. Once these issues are addressed in the screening of corridors and the designing of a concept of operations, it would be beneficial to focus on those corridors that meet the more rigorous screen- ing criteria and repeat the B-C analysis with new information about configurations and costs, esti- mate new demand volumes and re-set tolling and revenue forecasts to develop advanced financial models and establish the most cost-effective corridor configurations. 5.1.2 Productivity With respect to improving productivity and freight movement efficiency, truck-only lanes on long-haul corridors have two potential benefits: the potential to increase truck average speeds (truck mobility and the benefits of improved speeds on trucking productivity) and the potential to improve productivity through use of LCVs (productivity improvements due to increased pay- loads). Eliminating auto-truck interactions and addressing geometric issues could provide oppor- tunities to increase speeds on truck-only lanes. As described in the interim report, design of a roadway dedicated to trucks could focus on reducing roadway curvature and grades and improv- ing sight-distance geometries, thereby allowing for higher truck speeds while maintaining safety. Most of the studies reviewed for this project that focus on long-haul corridors show that the alternatives that incorporate LCV operations provide the greatest benefits. There is the potential for significant benefit to motor carriers and shippers from LCV operations (due to substantial pro- ductivity enhancements for motor carriers, and associated cost savings for shippers) and there is the potential to capture some of this value and finance the facilities through tolling schemes. If motor carriers can increase revenue without increasing many of their costs or without increasing them in proportion to the increase in payload, then these operations will be very profitable. These benefits are expected to be significant enough to be shared among motor carriers, shippers, and the public-sector providers of the LCV lanes. The analysis conducted in this study provides a frame- work for the estimation of total productivity benefits of LCV operations, which is based on an enhancement of the basic approach developed by the Reason Foundation, related to data inputs such as congestion and speeds.

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82 Separation of Vehicles--CMV-Only Lanes 5.1.3 Mobility The opportunity to reduce travel times along general purpose lanes from implementing truck- only lanes appears to be relatively limited in long-haul corridors. Although they may pass through or around congested urban areas, long-haul intercity truck corridors generally are not character- ized by high levels of congestion. The analysis suggests that the limited opportunity to reduce travel times on long-haul corridors would include cases in which a high volume route passes through many urban centers such that a typical long-haul trip would make it difficult for trucks to avoid traveling through at least one or more of these congested urban areas during peak peri- ods. Examples would include certain parts of the industrial Midwest (possibly I-70) and the I-95 corridor. The results compiled in the performance evaluation task corroborate this point, with truck-only lanes along long-haul corridors in Georgia estimated to provide around 20% savings in travel times along the general purpose lanes. This can be attributed to savings along corridor segments close to, or along, the periphery of the Atlanta metropolitan area with notable peak period congestion. One of the deficiencies of current research on travel time benefits of truck-only lanes in long- haul corridors has to do with the inability of existing travel demand models to take into account the operational benefits of separating trucks and autos. To some extent, this could be better cap- tured with a different approach to measuring passenger car equivalents (PCE) and incorporating this in the analysis. For example, the Southern California Association of Governments (SCAG) heavy-duty truck model incorporates variable PCE factors that are calculated for each link in the network during assignment. The PCE factors are adjusted based on road grade, level of congestion, and percent trucks. Taking this approach one step further, it could be useful to develop simulation models of the corridors in question to examine actual travel times with and without auto-truck separation. The American Transportation Research Institute (ATRI) is collecting data on corridor travel times and travel time reliability using GPS data sets from in-use trucks and these data, cou- pled with other local data sets, can be used to calculate differences in truck speeds and auto speeds with different levels of truck volumes. These can be used to help calibrate simulation models to take into account the flow characteristics of trucks as compared to autos. Using data on crash rates and other random events, the simulations also could be structured to see if there is any difference in recovery times between truck-only lanes and mixed-flow lanes. Thus, the simulations could pro- vide a better picture of the actual travel time benefits of separating autos and trucks under various traffic conditions. 5.1.4 Safety Given the large amount of truck VMT on certain long-haul intercity corridors, the ability to improve safety by separating trucks from autos appears to be an important issue. Also, safety impli- cations of truck-auto interactions would be a key issue along long-haul corridors with truck driver fatigue issues (due to long hours of driving) and significant nighttime truck traffic. There have been some studies and historic data from real-world projects that have highlighted the safety benefits of truck-auto separation, namely the Douglas report50, historic accident data for the New Jersey Turnpike, and the NCTCOG Truck Lane Pilot Study51. However, these studies and data are more representative of truck-auto separation in an urban corridor environment and, consequently, their discussion is presented under the discussion of urban corridors (Section 5.2). Clearly, there appears to be inadequate research into the safety benefits of truck-only lanes along 50 J. G. Douglas, Handbook for Planning Truck Facilities on Urban Highways, August 2004. 51 See

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Conclusions and Recommendations 83 long-haul corridors. The following sections present some discussion of potential approaches that could be undertaken to account for this research need. First, with the corridors identified by the Reason Foundation as high priority long-haul corri- dors for LCV operations as a starting point, it would be useful to conduct a much more compre- hensive national assessment of crash data as a function of the level of truck-auto interactions. This analysis would look at correlations between the level of truck-auto interaction as a function of total VMT to understand the relationship between level of truck-auto interaction and accidents. In addition, the analysis would conduct a more detailed examination of the conditions under which truck-involved accidents occur to the extent that this information is available in crash databases. One approach for doing this would be to develop regression models to estimate relationships between accident rates (by type of accident) and key parameters including level of congestion, truck shares of total traffic, grade, and number of lanes. Applications such as the Freeway Performance Measurement System (PeMS) developed by the University of California at Berkeley can be used to obtain incident data (including incidents by time of day and severity), which can be supplemented with other data inputs, such as truck and total traffic counts, to obtain truck shares to feed into a regression analysis framework. With this information it may be possible to predict lower crash rates due to the implementation of truck-only lanes. 5.1.5 Benefit-Cost Evaluation of Truck-Only Lanes on Long-Haul Corridors The primary objectives of the B-C analysis of truck-only lanes under the long-haul corridor sce- nario were the following: Assessing the B-C performance of truck-only lanes without LCV operations compared to adding mixed-flow capacity on long-haul corridors, and Assessing the incremental benefits and costs associated with LCV operations on truck-only lanes, and how these impact the B-C performance of this alternative compared to truck-only lanes without LCV operations and to adding mixed-flow capacity. As discussed in Chapter 4, a sensitivity analysis approach was used for the B-C analysis. Some of the key conclusions from the B-C analysis are summarized as follow: 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 exceed- ing the B-C ratio of adding more general purpose lanes; Given the high levels of diversion required to achieve a high B-C performance for truck-only lanes without LCV operations, which might not be achievable along long-haul corridors, par- ticularly those with relatively lower levels of congestion, truck-only lanes without LCV oper- ations would generally appear to be an inappropriate choice compared to adding mixed-flow capacity under the general conditions described for long-haul corridors. Based on the previous observation, it appears that for long-haul corridors, the decision making for corridor investment options primarily would be governed by the relative B-C performance of truck-only lanes with LCV operations compared to additional mixed-flow lanes. Even under the most optimal scenario, a minimum of 30% diversion would be required before the truck- only lane alternative with LCV operations becomes more cost-effective compared to adding mixed-flow capacity. This observation would be useful in analyzing the viability of implement- ing truck-only lanes with LCV operations along long-haul corridors, based on a market analy- sis of the diversion potential of truck-only lanes. The results from the B-C analysis 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