Passenger Car Equivalents for Heavy Vehicles in Work Zones

There are no Passenger Car Equivalents (PCE) values developed for work zones. Consequently the PCE values of basic freeway section are borrowed despite the reservations about their applicability to work zones. This paper extended the delay-based methodology that was developed for intersections to work zones, and developed PCE values for heavy vehicles in work zones. Delay is used for defining the equivalence because it captures the effects of the heavy vehicles better than headway. Simulation was used to quantify the delays caused by the heavy vehicles so PCE values can be determined. Delay and consequently delay-based PCE (D-PCE) values are affected by the length of the work zone, the speed difference between cars and heavy vehicles, traffic volume, percentage trucks and other work zone factors. The D-PCE values computed when there is a 10 mph speed difference between cars and heavy vehicles ranged from 2.8 to 7.7. The D-PCE values decreased with increasing heavy vehicle percentage and increased with volume.