Estimating Passenger Car Equivalent of Heavy Vehicles at Roundabout Entry Using Micro-Traffic Simulation

Abstract

Passenger Car Equivalent (PCE) is a unit used to represent the impact of a large vehicle on a road by expressing it as the number of equivalent passenger vehicles. This paper focuses on estimating the PCE of various sized heavy vehicles in roundabouts with respect to different entry flow rates. A single-lane roundabout was tested under predefined mixed traffic and demand scenarios in VISSIM micro-simulation environments. The individual and group behavior of four separate heavy-vehicle types were tested: single-unit trucks, buses, small semitrailers, and large semitrailers. The obtained PCE values were found to be on average lower than those suggested in the United States guidelines for roundabouts. The estimated PCE values for heavy vehicles in mixed traffic conditions are 1.30 for single unit trucks, 1.40 for small semitrailers, 1.60 for buses, and 1.70 for large semitrailers. Additional factors such as varying inflow (balanced, unbalanced, and congested traffic) show direct influences on the PCE values. The PCE value under these conditions ranged from 1.25 to 1.75 for smaller vehicles (single-unit trucks, buses, and small semitrailers) and 1.45-2.10 for larger heavy vehicles (large semitrailers). A general equation was developed based on the data to relate vehicle proportions and heavy-vehicle reduction factors that would be useful for professionals to analyze the operational performance of roundabouts with better accuracy.

The sustainability of shared mobility: Can a platform for shared rides reduce motorized traffic in cities?

“…PCE factors represent the number of passenger cars that would have an equivalent effect on the traffic flow (Zhou et al, 2019). PCE equivalency factors between 1.5 and 2.5 are common for trucks and buses according to size (TRB, 2010;Pajecki et al, 2019;Zhou et al, 2019). PCE values between 1.5 and 2.5 for minibuses, standard buses and large (BRT) buses are adopted in Table 4.…”

Estimation of Passenger Car Equivalents for Two-Lane and Turbo Roundabouts Using AIMSUN

“…With specific reference to roundabouts it should be noted that little information from specialized sources and published studies is still available on calculation of PCEs; see e.g., Giuffrè et al (2019), Pajecki et al (2019), Macioszek (2012), (Fortuijn, 2009a), Brilon (2005). The Highway Capacity Manual 2000, Highway Capacity Manual (2010), and Highway Capacity Manual 2016propose PCE values for heavy vehicles equal to two for all types of roundabouts.…”