A simulation study of truck passenger car equivalents (PCE) on basic freeway sections

Trucks have an effect on the quality of traffic flow on freeways. The passenger car equivalency of a truck represents the number of passenger cars that would have an equivalent effect on the quality of the traffic flow. This research estimated truck passenger car equivalents using simulation, based on traffic density. It investigates the effect of several characteristics related to freeway design, vehicle performance, and the traffic stream on truck passenger car equivalents. Traffic density is a good indicator of the driver's freedom to maneuver and proximity to other vehicles, and is consistent with the measure of effectiveness for freeways used in the Highway Capacity Manual (HCM)[TRB (Transportation Research Board), 1994. Special Report 209: Highway Capacity Manual, Third ed. Transportation Research Board, Washington, DC]. The Freeway Simulation (FRESIM) model, developed by the Federal Highway Administration, was used in this research. FRESIM is a microscopic, stochastic computer simulation model, capable of simulating the operations of traffic on freeways. Based on the output of numerous simulation runs, flow-density curves were developed, and passenger car equivalents were estimated for a wide range of design and traffic conditions, and a range of vehicle performance characteristics. These passenger car equivalents were compared to values provided in the 1994 HCM.