Urban Traffic Light Control Considering Capacity Difference Between Public Bus and Private Vehicles

Abstract

Due to the rapid growth of transportation demand for economic development, the importance of effective urban traffic signal control can never be underestimated, and the severe space saturation greatly limit the operations of a transportation system. In this paper, public buses and other vehicles are treated as different traffic flows. We address the urban traffic signal control problem in a scheduling framework by considering that the capacity of a public bus is much greater than that of other vehicles. The dynamics of an urban traffic network controlled by traffic lights are described by a novel model, which is formed by inserting mixed logical constraints into a cell transmission flow dynamic model. It includes the nonlinear relationship among the current link volume from the upstream, the current remaining link capacity from the downstream, and the state of the traffic lights. With the objective of minimizing the total delay time in a traffic network for people in the private vehicles and buses, we obtain a mixed integer linear programming formulation, which is built from the traffic signal control problem. We further analyze the influence of the number of passengers on buses and the time interval. The efficiency of the proposed method is verified by making comparisons between the models with and without considering the public transport regular. When the average number of passengers on a bus increases from 10 to 60, the degree of optimization ranges from 17% to 51% for the two-stage model and from 4% to 26% for the four-stage model. Finally, we consider the case without bus lanes and show the importance of dedicated bus lanes.

Keywords

• Public transportation system
• urban traffic signal scheduling
• mixed integer linear programming