Synthesis of Information Related to Highway Practices. Topic 55-20. Traffic Capacity Level of Service Adaptations and Usage

The Level of Service (LOS) concept has been used for over 50 years by state departments of transportation (DOTs) for policy setting, planning, analysis, and communication efforts. Individual adoption of the LOS framework by DOTs has generally been consistent with the Highway Capacity Manual (HCM) although usage and application may vary across different state DOTs. Some agencies may also have tailored their respective LOS definitions and applications for local conditions, multimodal analysis, and threshold values such as adjustment of HCM's hard-edged LOS category definitions (e.g., extrapolating or delineating failure conditions). Additionally, there are differences in how DOTs use big data and modern communication tools in their LOS analyses. The objective of this synthesis is to document practices of state DOTs use of the HCM LOS framework for traffic capacity and multimodal analyses.


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  • Status: Active
  • Funding: $55000
  • Contract Numbers:

    Project 20-05, Topic 55-20

  • Sponsor Organizations:

    National Cooperative Highway Research Program (NCHRP) Synthesis

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Nasri, Arefeh

  • Performing Organizations:

    ,   Germany 

    University of Kansas, Lawrence

    2600 Learned Hall
    Lawrence, KS  United States  66045
  • Principal Investigators:

    Kondyli, Alexandra

  • Start Date: 20240205
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01884753
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic 55-20
  • Files: TRB, RIP
  • Created Date: Jun 9 2023 12:43PM