Integrated Optimisation of Traffic Signals and Platoon Trajectories with Advanced Forward-looking Planning in the Connected Vehicle Environment

Traditional traffic control methods at signalised intersections primarily focused on optimising traffic signals without adequately addressing the coordination between signals and vehicles. Fortunately, with the advent of advanced vehicular communication technologies, real-time bidirectional communication between roadside infrastructure and vehicles has become feasible, significantly improving coordination between these elements. This paper presents a bi-level optimisation method for signalised intersections, enhancing arrive-on-green (AOG) performance in connected vehicles. By extending optimal control from a single dimension - whether spatial or temporal - to a two-dimensional spatial-temporal approach, we develop a comprehensive bi-level control framework. The framework includes outer-layer signal optimisation for maximising green utilisation and inner-layer platoon trajectory optimisation. Intermediate parameters and extended planning-time are proposed to improve solution finding. The effectiveness of the proposed joint optimisation method was evaluated through simulation case studies conducted in SUMO. The results showed increased efficiency and reduced stops, with stable, accurate control.