Traffic signals are one of the most commonly recognized symbols of traffic control by the general public. Even the most uninformed traveler recognizes the impact that traffic signals have on travel. Travelers are also surprisingly astute in realizing when signals do not meet their needs for efficient travel. In fact, the FHWA 2000 Omnibus survey results showed that improving traffic operations is a significant issue for travelers. When asked what they recommended to improve operations, “improve traffic signal timing” was the second highest response and “checking traffic signals often” was the sixth highest.

Well-timed and maintained traffic signals and elements of traffic management such as work zone operations, managing special events and traffic incident response, monitoring of traffic and weather conditions and removal of localized traffic bottlenecks are routine operations strategies of public agencies. However, continuing growth in passenger and freight traffic indicates that a more proactive approach will be necessary to resolve congested conditions and the resulting unreliable service to motorists. Proactive management is only possible with a good analytical foundation and an objectives-based plan for how the traffic signal systems should be operated. This foundation should include the use of appropriate performance metrics, targets for performance, appropriate analysis tools to identify, develop and evaluate solutions to operational problems and an investment plan and capable workforce necessary to implement the chosen solutions. This proactive approach to traffic signal operations also requires the use of a systems approach to determine the most appropriate investment in existing or new technology to enable the implementation of solutions to operational problems.

There is little doubt that signal timing has a greater impact on transportation system efficiency than any other operational measure in the traffic engineering toolkit. Delays experienced in highway travel have been steadily increasing during the past 20 years. Delays at traffic signals contribute an estimated 25 percent to this total. Thus there is little doubt that focusing on traffic signal timing has potentially enormous payoffs for the quality of travel experienced by the U.S. public.

National Report Card: How Are We Doing?

For years, transportation professionals have effectively identified pavement and bridge deficiencies and estimated the resources needed to maintain and improve those conditions. Traffic signals, a highly visible traffic operational tool, have not enjoyed the same level of attention.

NTOC, an informal coalition of associations interested in advancing transportation system management and operation, with support from the Federal Highway Administration (FHWA) developed a National Report Card on traffic signal operations. The National Report Card was to:

  • Bring attention to the current state of signal operation;
  • Create awareness of the congestion reducing benefits of good traffic signal operation; and
  • Make a case for additional investment in traffic signal operation.

The 2005 National Traffic Signal Report Card was released through a media event, on April 20, 2005. The results contained in the 2005 National Report Card were based on responses to the 2005 Traffic Signal Operations Self Assessment. More than 300 state and local governments completed the self assessment and returned the results for compilation into the 2005 National Traffic Signal Report Card. The 2005 National Traffic Signal Report Card showed that traffic signal operation in the U.S. scored a "D-". A "D-" means that traffic signals are not operating as efficiently as they could be, resulting in unnecessary delay to travelers.

Subsequently, NTOC released the 2007 National Traffic Signal Report Card on October 9, 2007 based on the results of more than 400 state, county and municipal agencies that completed the 2006 Traffic Signal Operations Self Assessment. While the score improved marginally to a “D” it did show that a number of agencies experienced a marked improvement by taking a critical look at their traffic signal management program and making targeted investments in infrastructure, systems and/or agency processes.

Institute of Transportation Engineers

American Association of State Highway and Transportation Officials

Federal Highway Administration

American Public Works Association IMSA Intelligent Transportation Society of America