OBJECTIVE This study applies a simulation technique to evaluate the hypothesis that red-light cameras (RLCs) exert important effects on accident risks. Conflict occurrences are generated by simulation and compared at intersections with and without RLCs to assess the impact of RLCs on several conflict types under various traffic conditions.
METHOD Conflict occurrences are generated through simulating vehicular interactions based on an improved Cellular Automata (CA) model. The CA model is calibrated and validated against field observations at approaches with and without RLCs. Simulation experiments are conducted for RLC and non-RLC intersections with different geometric layout and traffic demands to generate conflict occurrences which are analyzed to evaluate the hypothesis that RLCs exert important effects on road safety.
RESULTS The comparison of simulated conflict occurrences show favorable safety impacts of RLCs on crossing conflicts, and unfavorable impacts for rear-end conflicts during red/amber phases. Corroborative results are found from broad analysis of accident occurrences.
CONCLUSIONS The RLCs are found to impose mixed effect on accident risk at signalized intersections: crossing collisions are reduced while rear-end collisions may increase. The specially-developed CA model is found to be a feasible safety assessment tool.