Rhythmic Control Methodology For Urban Traffic Networks Under A Connected And Automated Environment

The rapid development of connected and automated technologies brings great potential for advanced urban traffic control.Considering the traffic problems of complicated conflict relations among vehicular movements,imbalanced distribution of traffic flows,and incompatibility of heterogeneous vehicles,this dissertation aims to develop an innovative rhythmic traffic control approach under a connected and automated vehicle environment to improve traffic efficiency and safety.To achieve the research objectives,this dissertation begins with the fundamental concept and model of rhythmic traffic control,extends to various methods for different traffic scenarios.The main contents are summarized as follows:(1)The novel and fundamental rhythmic traffic control philosophy is proposed for single intersections.By in-depth examining the relationship of vehicular conflicting movements,the road geometric layout and traffic control strategy are designed in a unified framework.The concept of virtual container is introduced to organize traffic in a highly-orderly manner,and jointly optimized with the intersection geometric layout,so the right-of-ways of intersection could be finely assigned and the space-time resources could be fully utilized.The approach could reduce the average vehicular delay to below10 seconds when the traffic saturation level reaches 90%.(2)The fundamental rhythmic traffic control strategy is extended over an urban network.A knotted intersection design is proposed to simplify the conflicting relations,and collaborated among adjacent intersections.The two-phase traffic control strategy is developed and achieves the nearly-optimum throughput of intersections.The knotted intersection design,space-time trajectories of virtual containers and network traffic flow assignment are jointly optimized to build up a network-level traffic control optimization model.The results show that the maximum traffic volume under rhythmic control strategy is twice as much as that under traditional signal control.(3)The multiple rhythmic traffic control approach is proposed for an urban network with imbalanced traffic distribution.Differential control rhythms are adopted for different areas according to the flow distribution,and various virtual containers are designed for different types of vehicles.Collaborated with lane configuration and traffic flow assignment,a joint optimization model is developed for the heterogeneous traffic control.The approach could reduce vehicular travel cost and improve network throughput under various demand cases.(4)The asynchronous rhythmic traffic control approach is proposed for the multimode traffic with transit buses and private cars.Dedicated virtual containers are designed for transit buses to provide priority of right-of-ways,and the travel itinerary planning of buses and the traffic flow assignment of private cars are jointly optimized.The results show that under the premise of priority treatment for buses,the approach could eliminate the efficiency damage for private cars and enhance the overall traffic efficiency.On the whole,this dissertation focuses on rhythmic traffic control,and follows the main line that begins with fundamental philosophy,optimization models,and ends with simulation validation,and develops a complete solution of urban traffic control approach under the connected and automated environment.The proposed approaches are expected to provide important reference significance for solving the current traffic problem and adapting to the future traffic development in urban cites.