A Schedule-based Strategy of transit signal priority and speed guidance in Connected Vehicle environment

Abstract

Transit signal priority (TSP) is a cost-effective way to improve transit system punctuality and efficiency. Connected Vehicle environment can provide precise and detailed information on vehicle movements, which is essential for effective TSP operation. This paper presents an integrated control strategy of TSP and speed guidance under the environment of Connected Vehicles. The strategy targets on buses running through an intersection with a dedicated bus lane installed and two adjacent bus stops located at the upstream and downstream. Aiming at improving bus punctuality and reducing negative impact (i.e. delay) on the general traffic of an intersection, this strategy controls transit operating speed and traffic signal by developing the following five models: a bus status judgment model, a bus dwelling model, a speed guidance model, a step-by-step signal priority control model, and a speed adjustment model. The bus dwelling model is developed for a bus arriving ahead of the schedule, and the speed guidance model is proposed for delayed buses. When the speed guidance model is ineffective, the signal priority control model will be considered. Two numerical examples are examined to test the performance of the proposed strategy. The results show that it can not only improve bus punctuality, but also reduce negative delay impact on other traffic flows entering an intersection.