Passenger Car Equivalents From Network Simulation

A key input in the critical movement analysis (CMA) methodology for intersection capacity estimation is the passenger car equivalent (PCE) of heavy vehicles. Despite the increasing use of CMA, little research has been performed to estimate PCEs as a function of vehicle type and traffic volume. This research develops and tests a procedure using a macroscopic traffic simulation model on an urban network to derive passenger car equivalent estimates for large vehicles as a function of vehicle size, signal timing, and traffic volumes. Results for urban arterials are presented for each of seven visual vehicle classification types, six different levels of service, and three types of signal settings. The results indicate that the estimates of PCEs increase as the traffic volume approaches forced flow conditions, vehicles get larger, and as the signal system approaches optimum. It is also shown that these values are generally lower than those used in the Highway Capacity Manual, the Interim Materials on Highway Capacity, or in Webster's traffic delay equations.