Implementation and optimization of group-based signal control in traffic simulation

Over the past decades, group-based control has become one of the most popular signal technologies being applied in many cities around the world. LHOVRA control is one of such group-based controls widely employed in Scandinavian countries. While several previous studies showed that group-based control outperforms stage-based control in many aspects, implementation and evaluation of signal controllers are complicated in a real application. In addition, little effort has been put in optimizing such group-based controllers in traffic management practice. This study implements generic group-based control in an object-oriented software framework, while a software-in-the-loop simulation is developed to integrate the signal controller with an open-source traffic simulator, SUMO. Also, stochastic optimization is applied to generate optimal signal parameters according to different settings of objective. In particular, part of the study is to improve the computational performance of the optimization process by parallelized simulation runs. Test-based experiments are finally carried out to evaluate traffic and optimize its impact on a small traffic network in Stockholm.