Examining the effect of heavy vehicles on traffic flow during congestion.

An investigation into the effect of heavy vehicles on traffic flow during congestion is presented in this paper. Empirical data and microscopic traffic simulation were used in the analysis. The simulation model was calibrated and validated using field data at two study sites in Ontario, Canada. One site is located on level terrain while the other is located on a 1 kilometer long 3 per cent upgrade. Simulation experiments were conducted using the calibrated model at the two study sites. The passenger car equivalency factor derived from the queue discharge flow was used as an indicator (measure of effectiveness) of heavy vehicles effect. While study results suggest some similarities between the free-flow and the congested regimes concerning the effect of heavy vehicles, some important differences exist due to the different mechanisms that govern heavy vehicles performance in the two regimes. Also, lane use restriction and the location of bottleneck relative to the upgrade were found to have considerable influence on heavy vehicles effect during congestion. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E213531.