Optimal transit signal priority method with conflicting requests under connected vehicle environment

In this research, an optimal transit priority signal timing decision method was proposed by minimizing the personal average delay, aiming at resolving multiple conflicting priority requests at an isolated intersection. Based on connected vehicle technologies, it is available to obtain detailed information including lane-level locations and speeds of connected vehicles, signal plans and light states of traffic lights, traffic flow rates and queueing lengths at the intersection. The proposed method reallocates green time of every two signal stages, where transits are weighted by their on-time performance, loading factors and passenger priority. The delay of transit is estimated in five scenarios according to bus arrival time and queueing behavior, while the delay of other traffic flows is calculated with respect to the adjustment of green time. The result shows that the transit signal priority control achieved 8%-40% reductions of average personal delay and balance of travel completion, depending on various volumes of transits and general traffic, compared against the cases without transit signal priority control or with fixed green extensions.