Estimating Passenger Car Equivalent using the HCM-6 PCE Methodology on Four-Lane Level Freeway Segments in Western U.S.

The passenger car equivalent (PCE) of a truck is used to account for the presence of trucks in the Highway Capacity Manual (HCM). The HCM-6 employed an equivalency capacity methodology to estimate PCE. It is hypothesized in this paper that the HCM-6 PCE values are not appropriate for the western U.S., which consistently experiences truck percentages higher than 25%. Furthermore, the HCM PCE procedure assumes that truck and passenger cars travel at the same desired free-flow speed on level terrain. However, many heavy trucks in the western U.S. are governed through the use of speed limiters so that their speeds are considerably less than the speed limit. Thirdly, the HCM-6 PCEs are based on the freeways having three lanes per direction, which might not be appropriate for the freeways with two lanes per direction that predominate in the rural sections of the western U.S. Lastly, the trucks used in the HCM-6 simulation might not be representative of the empirical trucks observed on rural freeways in western states. This paper examines these effects on PCEs using data from I-80 in western Nebraska. The PCEs were estimated using the HCM-6 equal-capacity method and VISSIM 9.0 simulation data under (1) the HCM-6 conditions and (2) the Nebraska empirical conditions. It was found that the PCEs recommended in HCM-6 underestimate the effects of trucks on four-lane level freeway segments that experience high truck percentages having large differences in free-flow speed distributions, and which have different truck lengths.

[1]  QiYan,et al.  Passenger car equivalents of trucks on four-lane rural freeways under lane restriction and different traffic conditions , 2012 .

[2]  Lily Elefteriadou,et al.  Development of Passenger Car Equivalents for Freeways, Two-Lane Highways, and Arterials , 1997 .

[3]  Ahmed Al-Kaisy,et al.  Developing passenger car equivalents for heavy vehicles on freeways during queue discharge flow , 2002 .

[4]  Ahmed Al-Kaisy,et al.  Car-Following Interaction and the Definition of Free-Moving Vehicles on Two-Lane Rural Highways , 2008 .

[5]  Hesham A Rakha,et al.  Developing Passenger Car Equivalency Factors for Heavy Vehicles During Congestion , 2005 .

[6]  윤태영,et al.  Transportation Research Board of the National Academies , 2015 .

[7]  Rahim F Benekohal,et al.  Delay-based passenger car equivalents for trucks at signalized intersections , 2000 .

[8]  George F. List,et al.  NCFRP Project 41 Incorporating Truck Analysis into the Highway Capacity Manual , 2014 .

[9]  Henry S.L. Fan.  Passenger car equivalents for vehicles on Singapore expressways , 1990 .

[10]  L. Rilett,et al.  Estimating Passenger Car Equivalents on Level Freeway Segments Experiencing High Truck Percentages and Differential Average Speeds , 2018, Transportation Research Record: Journal of the Transportation Research Board.

[11]  Beyond Traffic: Trends and Choices 2045—A National Dialogue About Future Transportation Opportunities and Challenges , 2017 .

[12]  P. Boggs,et al.  Sequential quadratic programming for large-scale nonlinear optimization , 2000 .

[13]  Yiik Diew Wong,et al.  Lane-harmonised passenger car equivalents for heterogeneous expressway traffic , 2015 .

[14]  Ahmed Al-Kaisy,et al.  Estimating Truck Equivalencies for Freeway Sections , 2007 .

[15]  S. Miaou,et al.  Exploration of the Relationships between Operating Speed and Roadway Features on Tangent Sections , 2005 .

[16]  Lily Elefteriadou,et al.  A simulation study of truck passenger car equivalents (PCE) on basic freeway sections , 1999 .