Making the Traffic Operations Case for Congestion Pricing: Operational Impacts of Congestion Pricing

Congestion begins when an excess of vehicles on a segment of roadway at a given time, resulting in speeds that are significantly slower than normal or "free flow" speeds. Congestion often means stop-and-go traffic. The transition occurs when vehicle density (the number of vehicles per mile in a lane) exceeds a critical level. Once traffic enters a state of congestion, recovery or time to return to a free-flow state is lengthy; and during the recovery process, delay continues to accumulate. The breakdown in speed and flow greatly impedes the efficient operation of the freeway system, resulting in economic, mobility, environmental and safety problems. Freeways are designed to function as access-controlled highways characterized by uninterrupted traffic flow so references to freeway performance relate primarily to the quality of traffic flow or traffic conditions as experienced by users of the freeway. The maximum flow or capacity of a freeway segment is reached while traffic is moving freely. As a result, freeways are most productive when they carry capacity flows at 60 mph, whereas lower speeds impose freeway delay, resulting in bottlenecks. The traffic engineering community has developed an arsenal of integrated tools to mitigate the impacts of congestion on freeway throughput and performance, including pricing of capacity to manage demand for travel. Congestion pricing is a strategy which dynamically matches demand with available capacity. A congestion price is a user fee equal to the added cost imposed on other travelers as a result of the last traveler’s entry into the highway network. The concept is based on the idea that motorists should pay for the additional congestion they create when entering a congested road. The concept calls for fees to vary according to the level of congestion with the price mechanism applied to make travelers more fully aware of the congestion externality they impose on other travelers and the system itself. The operational rationales for the institution of pricing strategies are to improve the efficiency of operations in a corridor and/or to better manage congestion. The objectives of this project were to: 1. Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the study of actual projects, and 2. Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the use of modeling and other analytical methods.

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  • Corporate Authors:

    Oak Ridge National Laboratory

    2360 Cherahala Boulevard
    Knoxville, TN  United States  37932

    Battelle Columbus Laboratories

    505 King Avenue
    Columbus, OH  United States  43201

    Department of Energy

    1000 Independence Avenue, SW
    Washington, DC  United States  20585
  • Authors:
    • Hu, Patricia S
    • Chin, Shih-Miao
    • Davidson, Diane
  • Publication Date: 2010-7


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Tables;
  • Pagination: 94p

Subject/Index Terms

Filing Info

  • Accession Number: 01495419
  • Record Type: Publication
  • Report/Paper Numbers: ORNL/TM-2010/147
  • Contract Numbers: DE-AC05-00OR22725
  • Files: TRIS
  • Created Date: Oct 8 2013 1:36PM