Quantum Annealing-Enhanced Virtual Traffic Lights and its Evaluation Using a Quantum-in-the-Loop Simulation Testbed

Abstract

Virtual Traffic Light (VTL) is a traffic control method that does not require traffic signal-related infrastructure for roadway intersections. Connected vehicles (CVs) are given right-of-way based on prevailing traffic conditions, such as estimated times of arrival (ETAs) of vehicles, the number of CVs in different approaches, and their emissions. These factors are considered in line with the objectives of the VTL application. Aiming to optimize traffic flow by reducing delays, VTL generates Signal Phase and Timing (SPaT) data for CVs approaching an intersection. Our VTL method considers the delay each CV would cause for other CVs if given the right-of-way. However, the stochastic nature of vehicle arrivals at intersections increases the complexity of the optimization problem, making it challenging for classical computers to determine optimal solutions in real-time. To address this limitation, we develop a VTL method designed to minimize stopped delays for CVs at an intersection by leveraging the efficacies of existing quantum computers that determine the best outcome from all possible combinations. This method employs Quadratic Unconstrained Binary Optimization (QUBO), a mathematical framework commonly used in quantum computing, to formulate the VTL problem as a stopped-delay-minimization challenge. To evaluate our method for roadway traffic with varying traffic volumes, we integrate an open-source microscopic roadway traffic simulator, Simulation for Urban Mobility (SUMO), with a cloud-based D-Wave quantum computer. Our analysis reveals that our quantum computing-supported VTL outperforms the classical optimization-based VTL by significantly reducing stopped delays at intersections and travel time through the roadway sections crossing the intersections.