Estimating the Social Cost of Congestion Using the Bottleneck Model

Modern consumers devote a large amount of money and time to commuting. According to the 2009 National Household Travel Survey, the average American worker spends about one hour every weekday commuting in an automobile. Some of that time is spent in delays caused by traffic congestion, and economists have long understood that such congestion is the most important source of inefficiency in highway transportation. Although the theory of traffic congestion has become one of the main themes in the field of transportation economics, empirical research quantifying the social cost of congestion is relatively rare. The main goal of this research is to fill that gap by providing new evidence on the social costs of traffic congestion, and to identify their determinants for guiding congestion-reduction policies. This project measures commuter's wasted time due to traffic congestion using a unique dataset that measures the trips and characteristics of individual commuters. The project will develop a new approach to measuring congestion delays, which is simple to estimate and widely applicable. Specifically, the project will first estimate how much time each commuter would have spent if she had experienced no congestion delays on her route. The project then compare this counterfactual travel time to the commuter's actual travel time and compute the difference. The project will exploit recent developments in econometrics to measure congestion costs in this manner. With those congestion-cost estimates, the project can then evaluate alternative policies designed to reduce traffic congestion. Within a traditional economic framework, the optimal policy is usually a congestion toll that depends both on time of day and location of traffic. However, that policy is often difficult to implement for various reasons, and policymakers must consider alternatives such as land-use reforms and highway construction or expansion. To evaluate those alternative policies, the project will identify geographic determinants of traffic congestion. Specifically, the project will examine variations in congestion costs by local geographic conditions, such as population and employment density, and other characteristics measured at the Metropolitan Statistical Area (MSA) level. This will yield an MSA-level index of traffic congestion, allowing the project to identify relationships between congestion and geographical characteristics, including roadway infrastructure and the availability of public transit. As a result, the project will address questions such as: are land-use controls (such as controls on population density) an effective way to reduce congestion? Are more sprawled cities more congested? Will building more highway capacity reduce congestion for travelers residing in the city? If so, how could its benefits be compared to its construction costs? This research aims at answering these questions from our novel theoretical and empirical framework.


    • English


    • Status: Completed
    • Funding: $52724
    • Contract Numbers:


    • Sponsor Organizations:

      METRANS Transportation Center

      University of Southern California
      Los Angeles, CA  United States  90089-0626

      National Center for Metropolitan Transportation Research

      University of Southern California
      650 Childs Way, RGL 107
      Los Angeles, CA  United States  90089-0626

      California Department of Transportation

      1227 O Street
      Sacramento, CA  United States  95843

      Office of the Assistant Secretary for Research and Technology

      University Transportation Centers Program
      Department of Transportation
      Washington, DC  United States  20590
    • Project Managers:

      Brinkerhoff, Cort

    • Principal Investigators:

      Kim, Jinwon

    • Start Date: 20170930
    • Expected Completion Date: 20180930
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01642994
    • Record Type: Research project
    • Source Agency: National Center for Metropolitan Transportation Research
    • Contract Numbers: 17-14
    • Files: UTC, RiP
    • Created Date: Aug 1 2017 7:23PM