Evaluation Of Transit Priority Strategies On Intersections Based On Cellular Automata Modeling

ABSTRACT:With the urban traffic congestion growing, public transport has increased its status in the urban transport system, and bus signal priority has become an important part of traffic signal control systems. The impacts of the transit signal priority control to general social vehicles and environment of intersections are worthy of studying. In this article, transit signal priority strategies for intersections under the condition of mixed traffic flow are analyzed, and integrated constraints, spatio-temporal constraints and resource constraints are established on active priority control. Based on cellular automata theory, the simulation program are taken for analysis of traffic flow at intersections. Specific elements include the following:(1)Cellular automata simulation model of mixed traffic flow. Based on the classic one-dimensional cellular automata model, through the analysis of mixed traffic flow operation characteristics, an improved VDR model for single lane and the improved lane-changing model for muti-lane are proposed, and cellular automata model of intersections without setting bus lanes is established.(2)Study of transit signal priority strategies. First, the transit priority strategies for intersections are classified to different angles as passive priority, absolute priority and conditional priority and analyzed respectively, with which multi-phase priority process is improved. According with this, the active transit priorities under multiple constrains are proposed, which include the spatio-temporal constraint considering delay and queue length and the resource constraint model taking into account fuel consumption and emissions.(3)The creation of the integrated constraints transit signal priority. Through correlation analysis of the indicators of spatio-temporal constrained model and resource constraint model, a combination of the two models is made to establish the integrated resource constrained transit signal priority model contains the indicators of number of buses, average vehicle delay and average vehicle fuel consumption.(4)Evaluation on effects of bus priority strategies. Based on MATLAB software, specific case are studied to simulate different transit signal priority strategies under different traffic flow conditions, and through analysis of the simulation results, different constraint conditions on the average delay, parking rates and other indicators have varying degrees of impact. Among the constraints, the integrated constraint model can better balance benefits of buses and social vehicles, and the indicators of fuel consumption and emissions under the condition can remain relatively stable.