Build support for operations and management activities by using data collected and archived to demonstrate data archival benefits.
National experience using archived traffic detector data for monitoring highway performance.
Made Public Date


United States

Lessons Learned: Monitoring Highway Congestion and Reliability Using Archived Traffic Detector Data


The Mobility Monitoring Program ( provides valuable insights with respect to using archived traffic detector data for monitoring highway performance (e.g., traffic congestion and travel reliability). The Mobility Monitoring Program was initiated in 2000 using archived freeway detector data from 10 cities. By 2004, the Program had grown to include nearly 30 cities with about 3,000 miles of freeway. Over the first four years of the Program, the project team gained valuable experience in the course of gathering archived data from State and local agencies. These experiences were captured in the report "Lessons Learned: Monitoring Highway Congestion and Reliability Using Archived Traffic Detector Data." The lessons documented in this report focus on three general areas: analytical methods, data quality, and institutional issues. They are useful to the Federal Highway Administration (FHWA) as it expands the national congestion monitoring program and to State and local agencies as they develop their congestion monitoring capabilities.

Lessons Learned

Public agencies typically struggle with their budgets. As a result, many transportation operations divisions have to justify their expenditures on operations and management activities or risk having their budget cut or diverted to other programs.

  • Reformulate data collected and archived while managing the transportation system to demonstrate the benefits of operations and management activities. The reuse of operations data for analytical purposes requires at least two things: 1) foresight to develop information systems that support real-time traffic management activities as well as historical analyses, and 2) commitment to collect and maintain quality data that can be used to demonstrate the benefits of operations. Such processes have long been in place in DOTs in the form of asset management systems such as those for pavement and bridge management. Operations must compete for resources internally with these interests who are usually better equipped with "hard" information about system conditions and expected benefits. Archived operations data can help to "level the playing field".
  • Anecdotal evidence from several states points to cases in which the value of operations activities was questioned by state legislators or upper-level managers within a state DOT. For example, an operations manager from Minnesota DOT highlighted the importance of accurate data in maintaining political support for the agency's incident response team. Members of the state legislature were questioning the value of the freeway service patrol, suggesting that the state agency could not afford to change commuters' tires and give away free gas. However, with their archived data, Minnesota DOT was able to show that the freeway service patrol was the initial detection source for about 20 percent of incidents that blocked state highways. Based on its quick access to this data, Minnesota DOT was able to respond to the legislators. In fact, the DOT is now looking for innovative ways to expand its freeway service patrol with its new-found support. The state DOT manager attributed this to the DOT's ability to access and analyze quality archived data.

This experience points out that when justifying expenditures, transportation operations divisions should consider how their data collection and archival positively affect traffic management and operations activities. This approach can help "level the playing field" when competing with other divisions for funding.

Lessons Learned: Monitoring Highway Congestion and Reliability Using Archived Traffic Detector Data

Lessons Learned: Monitoring Highway Congestion and Reliability Using Archived Traffic Detector Data
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Shawn Turner, Rich Margiotta, and Tim Lomax
U.S. Department of Transportation, Federal Highway Administration

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