Evaluation of Alternative Truck Lane Management Strategies along a Section of I-81 [2008]

US Transportation Collection2008PDFResearch PaperRakha, HeshamPark, SangjunArafeh, MazenEl-Shawarby, IhabVirginia Tech Transportation InstituteVirginia Tech Transportation InstituteVirginiaInterstate highwaysTruck lanesTruck facilitiesMicrosimulationMathematical modelsTruck trafficSlow lanesI-81 is one of the top eight truck routes in the U.S. In the state of Virginia, I-81 traverses 325.51 miles from Tennessee in the south to the West Virginia border in the north and passes through 12 counties. The highway was designed for a 15 percent truck volume, however trucks now account for somewhere between 20 to 40 percent of the total traffic volume. In 2001, the Virginia Department of Transportation (VDOT) developed a list of key improvements for I-81. The improvements include: developing the corridor as a multi-modal facility, incorporating a high degree of efficiency and safety for all users, which may include the physical separation of commercial and passenger vehicles; considering transit or other higher occupancy travel in and around growing urban areas, and using Intelligent Transportation Systems (ITSs) as short-, mid-, and long-term solutions to improving transportation flow and management (VDOT 2004). In 2003, a U.S. house transportation bill included $1.5 billion in federal funding for dedicated truck lanes. According to Representative Don Young (Alaska), author of the bill and a strong proponent of truck-only lanes, "Separate lanes for trucks will move freight more efficiently and make our highways significantly safer.\u201d Mr. Young expressed interest in making I-81 a national pilot project (2005). In 2005, FHWA approved the Tier 1 Draft EIS (VDOT 2005). Some of the key findings of the study were: (a) 2004 traffic volumes will nearly double by 2035; (b) Nearly the entire corridor needs additional capacity by 2035; (c) Estimates of future traffic volume do not support building two additional lanes in each direction for use only by trucks. Such a design would provide too much roadway capacity for trucks and not enough capacity for cars; and (d) Up to 37% of I-81 requires one additional lane in each direction, while much of the remainder may need up to two additional lanes in each direction to handle future traffic. In 2006, a cross-functional group of VDOT engineers recommended a number of measures, including: (a) building dedicated truck climbing lanes at selected locations; (b) increasing the number of on- and off-ramps; (c) installing guardrails along narrow medians to help prevent crossover crashes; and (d) correcting horizontal curvature problems, among others. Based on these recommendations and the Tier 1 EIS, FHWA concluded that there is an immediate need for smaller, independent safety and operational improvements along I-81. These short-term improvements include truck climbing lanes from approximately Milepost 195 to Milepost 202 northbound and Milepost 128 to 119 southbound with funding identified in SAFETEA-LU (FHWA 2007b). This report compares alternative truck and lane management strategies along a significant grade section of I-81 in the state of Virginia. These strategies are compared in terms of the transportation system efficiency, energy consumption, environmental, and safety impacts using microscopic traffic simulation. The study then conducts a benefit-cost analysis to compare all alternatives in an objective manner. Network-level impacts are determined from an analysis of microscopic simulation results using the INTEGRATION traffic simulation software (Van Aerde and Rakha 2007a; Van Aerde and Rakha 2007b). Four scenarios are analyzed. The first scenario is the base case with no addition of lanes. The second scenario involves adding an additional lane from milepost 125 to 120.7 and restricting the median lane to cars only from milepost 128 to 118. The third scenario is identical to scenario 1, with one additional lane from milepost 128 to 118. The two leftmost lanes within the 4-lane sections are dedicated as car-only lanes while a single lane is dedicated to cars only for the section from milepost 125 to 120.7. The final scenario is identical to Scenario 3 with the addition of a forth lane from milepost 125 to 120.7 and restricting the two leftmost lanes to light-duty vehicles only. The first section provides a brief background of the spatial and temporal scope of the Study Area, the concepts used to define the different management strategies and the measures of effectiveness (MOEs) considered as part of this study. Subsequently, a description of the calibration procedures that were utilized to calibrate the traffic simulation software, including the data collection efforts that were conducted and the input parameters is presented together with the procedures used to extrapolate future demands. The next section presents a summary of how the network was constructed and the results of the simulation runs. Subsequently, a benefit-cost analysis is described. Finally, the conclusions of the study are presented together with recommendations for further research.132