Signal control method and performance evaluation of an improved displaced left-turn intersection design in unsaturated traffic conditions

This paper proposes an improved layout for the Displaced Left-turn (DLT) intersection by combining the conventional DLT intersection with protected left-turn phases, based on the safe-crossing requirements of pedestrians and non-motorized vehicles. The delay and stops are weighted to form an integrated performance index (PI) in a real-time vehicle-to-infrastructure communication environment. The PI models, pertaining to all vehicles in non-DLT lanes, DLT lanes and shared through-right lanes are established based on the improved DLT intersection in unsaturated traffic conditions. In addition, a dynamic optimized method of traffic signal timing parameters is constructed based on minimizing average PI per vehicle and considering the traffic signals’ coordination at the main intersection and left-turn crossovers. The operational performance of the optimized method is validated using data collected at an intersection in Harbin, China.