Effects of Traffic Variability on the Number and Start Time of Signal Timing Plans
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Date
2021-11-30
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Abstract
Traffic volume at any intersection varies with time. Amount and pattern of variation can differ depending on the nature of the area, population composition, and other factors. Regardless, addressing that variation in traffic volume when designing timing plans at an intersection is essential to optimize its performance. Specifically, selecting when to initiate a timing plan can play a major role in improving the signal’s operation. Therefore, in this study, two methodologies were developed to optimize the selection of breakpoints of timing plans at a pretimed signalized intersection based on the minimization of delay. The developed techniques generate different alternatives of timing plan breakpoints and select the optimal set of breakpoints based on their performance. To validate the proposed methodologies, traffic counts were collected on two consecutive days in two intersections in College Station, TX. The counts were collected by, first, recording videos of the traffic and then analyzing those videos by a computer program, developed by the author, which can detect and count vehicles in the recorded videos. The developed optimization methodologies were applied on the collected data by utilizing a computer program which was also developed by the author based on the proposed optimization techniques. Timing plan breakpoints were generated by the optimization process. The results showed the ability of the developed optimization techniques to minimize delay and select, accordingly, the optimized breakpoints of timing plans. Also, by comparing the results with the results of the traditional AM peak, PM peak, and off-peak plan set, the developed techniques were found to be more effective in selecting the breakpoints of timing plans.
Furthermore, it was found that the critical zone optimization method performed better because it produces breakpoints that causes slightly less delay. Additionally and most importantly, the critical zone optimization method produces more alternatives of timing plan breakpoints that might perform relatively similar to the optimal breakpoints. This can help local agencies to freely select the breakpoints that can fit their requirements.
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Intersection, timining plan, traffic, signal