Hardware-in-the-Loop Simulation for Assessing Red-Light Violation Warning Application With Semi-Actuated Signal Control in a Connected Vehicle Environment

Understanding the safety and mobility impacts of connected vehicle (CV) applications is critical for ensuring effective implementations of these applications. This study provides an assessment of the safety and mobility impacts of the red-light violation warning (RLVW), a CV-based application at signalized intersections, under semi-actuated signal control utilizing a hardware-in-the-loop simulation environment. With actuated traffic signal operations, there is uncertainty in the end-of-green information provided to the vehicles using CV messages. The RLVW algorithm lacks the input information about when exactly the phase is going to be terminated since this termination occurs when a gap of a particular length is encountered at the detector. This study investigates a method recently proposed in a national effort to provide an assured green period (AGP) to grant definitive times for when the green interval will end. AGP mitigates the uncertainties related to termination of the green signal associated with actuated signal control and is expected to improve the performance of the CV RLVW application. Results showed that the safety benefits of RLVW without the use of AGP were limited. On the other hand, by introducing AGP with 100% RLVW, the number of red-light running events at signalized intersections was reduced by approximately 92%. However, the application of the AGP, as applied and assessed in this paper, can increase the number of stops and approach delay. This issue will need to be further investigated to determine the optimal setting of the AGP considering both mobility and safety impacts.