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.
ATCS ideally outperform the traditional systems when the system is experiencing non-recurring congestion, such as that caused by incidents and special events. The benefits of these systems were mainly measured by either before and after studies or on and off studies (where the ATCS is switched off during the study period). Performance measures used to evaluate the operational efficiency of an ATCS over a traditional timed signal system include reduction in delays and number of stops.
- Of the agencies with ATCS installed that were surveyed, 71 percent felt that ATCS outperformed their previous system.
- Overall, 60 percent of agencies observed a reduction in travel time/delays when the system was deployed.
- Similarly, 37 percent observed reductions in the number of stops, as well as intersection delays.
- Additionally, reductions in queue lengths were seen by 23 percent of agencies. Increased average speeds were observed by 35 percent of the agencies.