The Effects of Data Inaccuracy on the Performance of Traffic Signal Timing Plans

This paper explores the performance of signal timing plans calibrated with perfect or imperfect information. The arrival information considered include arrival rates and arrival distributions. The study is conducted for different levels of arrival rates and different forms of arrival distributions under a wide range of arrival information inaccuracy, traffic intensity, and intersections with balanced and unbalanced flows.Our results indicate that the increase in delay, the number of stops, and queue length is in general insignificant when the arrival distribution used to calibrate the optimal timing plan is over- or under-estimated. For the same level of over- or under-estimation, the increase in delay and other measures can be high only when the flow level is very high. The effect, however, is attenuated for overestimation of flow since the cycle length is bounded by a predetermined upper bound. Overall, underestimation of flow appears to be more serious than overestimation of flow in terms of increase in total delay.