Evaluation of the Virginia Department of Transportation adaptive signal control technology pilot project.

Details

• Creators:
  Fontaine, Michael D. ; Ma, Jiaqi ; Hu, Jia
• Corporate Creators:
  Virginia Center for Transportation Innovation and Research
• Corporate Contributors:
  Virginia. Dept. of Transportation
• Subject/TRT Terms:
  • Adaptive control
  • Traffic signal control systems
  • Pilot studies
  • Traffic signal timing
  • Periods of the day
  • Bayes' theorem
  • Benefit cost analysis
• Publication/ Report Number:
  VCTIR 15-R24
• Resource Type:
  Tech Report
• Geographical Coverage:
  Virginia
• Corporate Publisher:
  Virginia Center for Transportation Innovation and Research
• Abstract:
  Currently, most traffic signals operated by the Virginia Department of Transportation (VDOT) use actuated plans that vary ; by time of day (TOD) and day of the week. These timing plans are typically developed off-line using traffic count information ; collected in the field and then processed using signal optimization software. This method works well as long as traffic volumes ; remain consistent with the conditions used to develop the timing plan, but timing plans can become suboptimal if traffic demands ; deviate from those conditions. Traffic growth over time, seasonal changes in traffic, special events, or incidents can all cause ; TOD plans to perform poorly, resulting in increased delays to drivers. As a result, VDOT must regularly retime signalized ; intersections to deal with long-term changes in travel patterns, which incurs costs to VDOT. Even so, non-recurring events can ; still cause TOD plans to perform poorly. ; Adaptive signal control technology (ASCT) is one tool that has been proposed to handle variable traffic demand better. ; VDOT’s Traffic Engineering Division began a pilot program to install the InSync ASCT developed by Rhythm Engineering on ; 13 corridors around the state beginning in 2011. The InSync system uses enhanced detection along a corridor to adjust signal ; timing parameters dynamically to meet observed demand in real time, eliminating the need to develop static timing plans. This ; allows the ASCT system to adjust signal timing parameters to account for variations in flow attributable to special events, ; seasonal flows, incidents, or simply the increase of volumes over time. In this case, signal timings are not pre-defined based on ; historic data, so ASCT systems can potentially reduce delays created by outdated static TOD plans. ; These pilot deployments were evaluated to determine if ASCT created operational and safety improvements large enough ; to justify the additional costs to install ASCT. Data on mainline traffic operations, side street delays, and intersection crashes ; were collected with and without ASCT active. The results showed that mainline traffic operations generally improved if (1) the ; corridor was not oversaturated; (2) the corridor did not have characteristics that encourage platoon dispersion; and (3) the ; corridor did not already function well. Side street delays generally increased, although net benefits in overall corridor travel time ; were usually still observed. An empirical Bayes safety analysis of crashes at the intersections where ASCT was installed also ; found a 17% decrease in total crashes. Overall, ASCT generally produced a favorable benefit/cost ratio. The findings from the ; pilot tests were used to identify key considerations for future ASCT deployments so that VDOT could better identify future sites ; that might benefit from ASCT installation.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29013/dot_29013_DS1.pdf
• File Type:
  [PDF - 556.94 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:54a6d49676878bf7962a445949a65a6531ffd06ac8486cbe790c67a81733e47e7f0019671732836376ca7c2cba307b29e008259dbbff7f27eda9e76123a7dbe1