Commit to acquiring the proper level of staffing and knowledge required for the operations and maintenance of Adaptive Traffic Control System (ATCS) prior to deployment.
Lessons learned from a synthesis of domestic and foreign state of highway signal control practice.
Made Public Date


United States





NCHRP Synthesis 403 Adaptive Traffic Control Systems: Domestic and Foreign State of Practice


A study published in 2010 reported the survey results of agencies with Adaptive Traffic Control Systems (ATCS). The survey results described the benefits and lessons learned acquired by domestic and foreign ATCS agencies in terms of working principles of ATCS, aspects of training, institutional factors, and benefits. Responses were obtained from 34 of 42 agencies in North America (an 81% response rate) and included city agencies and state Departments of Transportation (DOTs) in Arizona, Arkansas, California, Delaware, Florida, Georgia, Michigan, Minnesota, Missouri, North Carolina, Ohio, Oregon, Texas, Utah, Virginia and the state of Washington. Canadian agencies that participated in the survey included the ATCS vendor Econolite Canada and ATCS user agencies from the cities of Halifax, Red Deer and Toronto. International survey participants included ATCS agencies in Ireland, New Zealand, Australia, Chile, the United Kingdom, and China.

Lessons Learned

Adaptive Traffic Control Systems (ATCSs) are powerful and complex tools that require a level of expertise for proper maintenance and operations. ATCS may be viewed as a labor-reducing way of deploying signal timing plans, the experience of domestic and international ATCS agencies demonstrates the importance of having the level of staffing and knowledge in ATCS required for maintenance and operations. Key recommendations for ATCS agencies to consider in training, operations, and maintenance include the following.

  • Beware of the perception that an ATCS is a hands-off type of system that will lower the labor or expertise requirements compared to standard traffic control systems. There can be a belief or assumption among practitioners that an ATCS has the potential to reduce levels of labor or expertise required for standard traffic control systems because it eliminates the repetitive development of signal timing plans. However, deployment experience demonstrates that successful applications require ATCS expertise within an agency as well as proper levels of staffing. Yet, the NCHRP synthesis revealed that most ATCS vendors did not provide the training necessary for users to fully utilize their ATCSs. Instead, vendors trained users to the skill level required for supporting common every-day operations but not to the ability to customize their systems. Thus, ATCS agencies are compelled to hire vendors and/or consultants when faced with out-of-the-ordinary problems, such as adding or reconfiguring an intersection. Most ATCS agencies reported that they do not have enough staff to operate and maintain their ATCSs to the fullest potential.
  • Be certain to receive ATCS training not only during the initial deployment of ATCS, but continuously throughout initial validation to solve operational problems or issues as they arise. The training that agencies receive when the ATCS is first installed may not be sufficient after the initial deployment. As the ATCS becomes operational, operational issues are likely to develop. ATCS agencies should ensure that training would be available for staff to acquire the skills and knowledge needed to resolve emerging issues throughout the life of the ATCS. As shown by the NCHRP synthesis, many ATCS agencies received training that allowed them to operate their system fully, but some of the users received just a few days of training, which was not enough for them to fully operate the system. In contrast, some users received vendor support for the first 3 to 4 months of deployment.
  • Develop a working understanding of the principles of an ATCS. Having a working knowledge of the principles of an ATCS is one of the major factors underlying an operationally successful deployment. A survey showed that most ATCS users did not find the working principles of their ATCS to be difficult, although some (18%) did. However, surveyed ATCS users found the systems to be more demanding for operations than conventional traffic control systems. Once an ATCS is in place and after initial validation of the system is completed, ATCS users who have acquired a working knowledge of their system rely on their own (in-house) expertise. Agency’s financial resources play a role as well. Not surprisingly, agencies with greater financial resources are more likely to develop and retain in-house expertise.
  • Beware that implementing successful ATCS operations may require a switch in the type of labor from maintenance to operations. Whereas conventional systems are maintenance- intensive and rely on labor to maintain signal timing plans, ATCSs require expertise to successfully implement adaptive signal operations sensitive to real-time traffic conditions. In addition, ATCS components (e.g., hardware, software, and communications) may be more complex than those of standard traffic control systems, requiring specialized knowledge. ATCS agencies reported that the single most important factor in alleviating institutional barriers for the deployment of ATCS was having (and retaining) skilled engineering staff that had received training on ATCS operations. Although agencies reported that ATCS operations are not difficult, their experience has been that fully operating an ATCS system is possible only with training. Without proper levels of in-house expertise or staffing levels, users may find themselves having to hire external consultants to maintain the system if financial resources allow. If not, the performance of an ATCS can suffer.

ATCS deployments can bring significant benefits to traffic performance, but it requires a commitment to training and acquiring proper levels of staffing for operations and maintenance. ATCS operations are sufficiently complex that traffic engineers, in general, need at least four to six months to acquire a general understanding of these systems (in contrast to an experienced signal timing engineer who needs about two months). Indeed, one of the most important ATCS issues for smaller agencies is retaining ATCS-proficient staff. Acquiring the proper knowledge and technical expertise to operate an ATCS empowers an agency to maintain the system and realize substantial benefits to users of the transportation network in which it is deployed.

NCHRP Synthesis 403 Adaptive Traffic Control Systems: Domestic and Foreign State of Practice

NCHRP Synthesis 403 Adaptive Traffic Control Systems: Domestic and Foreign State of Practice
Publication Sort Date
Aleksandar Stevanovic, Advanced Transportation Concepts, LLC
Transportation Research Board

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System Engineering Elements

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