Sensitivity Analysis of Speed Limit, Truck Lane Restrictions, and Data Aggregation Level on the HCM-6 Passenger Car Equivalent Estimation Methodology for Western U.S. Conditions

In the 2016 Highway Capacity Manual (HCM-6), the impact of trucks on freeway operations is measured by passenger car equivalents (PCEs). PCEs are estimated by the equal capacity methodology. The HCM-6 PCE values are based on the assumptions that passenger cars and trucks travel at the same free-flow speed, that they travel on freeways with three lanes per direction, and that they travel in traffic with no more than 25% trucks. On Interstate 80 in western Nebraska, it is observed that the interaction of high truck percentages and large speed differences between passenger cars and trucks may result in moving bottlenecks. It was hypothesized that the current HCM-6 PCEs may be not appropriate for these conditions. A companion paper showed this was true and that the major cause was speed differentials between trucks and passenger cars. In essence, when slow-moving trucks pass each other they create moving bottlenecks, which results in increased PCE values. This paper is an extension to a companion paper and examines a number of issues related to estimation of PCEs. The paper examines the effect of speed limit, truck passing restrictions, and data aggregation interval on PCEs. The results show that: (i) if a higher speed limit is implemented, trucks will affect the passenger cars more severely; (ii) if truck passing is restricted by lane restrictions, the negative impacts of trucks on passenger car operation may be mitigated; and (iii) using a longer data aggregation interval results in lower PCE values, all else being equal.

• Record URL:
  • https://doi.org/10.1177/0361198119851451
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03611981
• Supplemental Notes:
  • The Standing Committee on Highway Capacity and Quality of Service (AHB40) peer-reviewed this paper (19-02463). © National Academy of Sciences: Transportation Research Board 2019.
• Authors:
  • Zhou, Jianan
  • Rilett, Laurence
  • Jones, Elizabeth
• Publication Date: 2019-11

Language

• English

Media Info

• Media Type: Web
• Features: References;
• Pagination: pp 493-504
• Serial:
  • Transportation Research Record: Journal of the Transportation Research Board
  • Volume: 2673
  • Issue Number: 11
  • Publisher: Sage Publications, Incorporated
  • ISSN: 0361-1981
  • EISSN: 2169-4052
  • Serial URL: http://journals.sagepub.com/home/trr

Subject/Index Terms

• TRT Terms: Case studies; Four lane highways; Free flow speeds; Freeways; Passenger car equivalence; Rural areas; Sensitivity analysis; Speed limits; Trucks
• Candidate Terms: Data aggregation
• Identifier Terms: Highway Capacity Manual 2016
• Uncontrolled Terms: Lane restrictions; Moving bottlenecks
• Geographic Terms: Nebraska; Western States
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 01708182
• Record Type: Publication
• Files: TRIS, TRB, ATRI
• Created Date: Jun 23 2019 5:02PM