Measuring Passenger Car Equivalents (PCE) for Heavy Vehicle on Two Lane Highway Segments Operating Under Various Traffic Conditions

Abstract

Passenger Car Equivalent (PCE) is essential for transportation engineering to assess heavy vehicles’ (HV) impact on highway operations and capacity planning. Highway Capacity Manual 2010 (HCM 2010) used PCE values and percent of heavy vehicles to account the impacts on both highway planning and operation, however, PCE values in the latest version of HCM derived based on the steady and balanced two-lane-two-way (TLTW) traffic flows. The objective of the study is to identify PCE values for TLTW highway at various traffic volume with an emphasis on congestion conditions. This study introduces an analytical model, combining a headway-based and a delay-based algorithms, for estimating PCEs of HV on a TLTW highway. This study contributes to the literature by providing relationships among PCE, the traffic volume level (TVL) of both lanes, and the TVL duration on a TLTW highway. Traffic volume was categorized into five levels: TVL A (<250 pc/h), TVL B (250–375 pc/h), TVL C (375–600 pc/h), TVL D (600–850 pc/h), and TVL E (>850 pc/h). The results indicate that on a TLTW highway, the TVLs of both lanes and their durations have significant impact on PCE values. In general, PCE values increase as TVL duration increases. Trucks have much higher impacts on operation under unbalanced conditions of TVL A with D, TVL B with C, and TVL D with B, when duration time is greater than one hour. When both lanes are saturated, trucks’ effect on capacity diminishes over time, and PCE values are approaching to 1.0.

Applying Two-parameter Weibull Distribution to Model Stochastic Capacity of Arterial Roads During Peak Hours due to Changing Proportion of Heavy Vehicles

“…The proportion of HVs in the traffic stream is not either monotonic or linear. The results in Table 3 are consistent with the assumption from a past study that the PCE value is considered insensitive to the level of HVs presence in both undersaturated and saturated traffic conditions [6]. It is likely that as the level of congestion increases, the presence of HVs becomes more obvious and interrupts traffic flow when compared to the absence of HVs.…”

“…PCE factor measures the magnitude of large vehicles' effect on the following traffic compared to passenger cars. In other words, PCE factors have a significant impact on road capacity and LoS [6].…”

“…HVs consume more road capacity than passenger cars and have a greater impact on oncoming traffic. Measuring such differences is therefore of great importance for local governments and other authorities to address road design and congestion challenges [6].…”

“…Since HVs are longer than other vehicle types, the distance between vehicles is longer. HVs occupy more space on the road than passenger cars and have a greater impact on oncoming traffic [6]. The impedance that different types of his HVs pose to other vehicles in mixed traffic affects the overall capacity and level of service (LoS) of highways [7].…”

Modeling Traffic Flow, Energy Use, and Emissions Using Google Maps and Google Street View: The Case of EDSA, Philippines

“…Second, a future research study should develop updated values of PCEFs considering the current traffic characteristics of Philippine highways. Relevant literature in measuring PCEFs includes [55,74,75]. To reduce uncertainty in data, a probabilistic analysis could be used to improve the robustness of the results.…”