Effectiveness of Alternative Detector Configurations for Option Zone Protection on High-speed Approaches to Traffic Signals

Safety and efficiency are both prime issues of concern at high-speed signalized intersections. However, although safety problems at high-speed signalized intersections can be mitigated by the application of detector configurations with option zone protection, such configurations can themselves create problems. For example extending the green indication to the maximum time can create max-out situations which terminates the phase without regard for vehicle location. The detector configurations with option zone protection may also produce higher delay times for vehicles on other approaches at the intersection.

In this study, four detector configurations with option zone protection features-- the Single Detector configuration, the SDITE configuration, the Beirele configuration, and the Bonneson configuration, are compared through computer simulation on their effects relative to the number of vehicles in the option zone, max-out occurrences, and average vehicle delay. The comparison suggests that although each configuration has its own advantages and disadvantages, the Bonneson detector configuration, in most circumstances, yields lower number of vehicles in the option zone per cycle and less average delay.