UC Irvine

Traditional traffic control has been based on collective stop-and-go movements for over a century. This dissertation explores the potential integration of scheduling for individual vehicle movements as a new paradigm for next-generation traffic control, which can be developed to avoid forced vehicle stoppage and queuing that is inherent in current urban traffic control. Inspired by its proven efficiency and safety in various transportation modes such as railway systems and air traffic controls, individual scheduling shows a promising perspective in urban traffic management to optimize traffic throughput, reduce traffic congestion, and enhance the overall traffic system performance. Supported by the rapid developments in driver assistance technologies and advanced real-time communication systems, such as in-vehicle indication devices and vehicle-to-everything communications, the integration of individual scheduling into urban traffic management holds the potential for improving the traffic efficiency under current traffic control schemes through eco-driving schemes, and ushering in a new paradigm of smart and efficient transportation systems in the future through the Link-based traffic control concept. Furthermore, this dissertation proposes a mathematical model, i.e., the Vehicle Tube Model, for traffic safety analysis under various vehicle behaviors.

The individual scheduling is first implemented for various traffic scenarios under traditional urban traffic control management. The scheduled information for individual vehicles includes the speed and time, and each vehicle is guided by an eco-driving vehicle control approach to fulfill its scheduled information. Considering various levels and requirements on vehicle connectivity and control complexity, this dissertation proposes three vehicle control approaches that respectively provide the advisory speed, two-stage advisory speed limits, as well as the optimal acceleration rates to adjust individual vehicle movements. Each approach can be independently implemented for each vehicle to improve the speed and decrease the speed oscillations. Through a set of simulation studies, the dissertation demonstrates significant improvements in vehicle speed, fuel consumption, and emissions reduction, underscoring the benefits of adopting individual scheduling under signalized intersection controls as well as for traffic flows on a freeway after a slowly moving vehicle.

With the implementation of scheduled individual vehicle movements, the dissertation introduces the innovative concept of Link-based traffic control, which represents a paradigm in contrast to the traditional node-based control such as the signalized control. The new paradigm further improves travel times and mobility and leads to smoother eco-driving through the development of optimized schemes to schedule movements that use traffic stream gaps. Emphasizing vehicle controls along the traffic links rather than at individual intersections as nodes, the Link-based traffic control schedules each vehicle movements to enable traffic flows from conflicting directions to pass through the intersections within the same period, thereby significantly enhancing the overall traffic throughput and fuel efficiency. This dissertation proposes four Link-based control models to schedule the speed and time for each vehicle when entering the intersection, and the comprehensive simulated results show that the traffic efficiency is dramatically increased with the Link-based control concept.

Moreover, the dissertation proposes the Vehicle Tube Model, as a dynamic representation of vehicle movement and theory for analytical traffic safety analysis. By quantifying the risk probabilities associated with potential collisions under current and future traffic scenarios, this framework provides valuable insights into the safety performance of future urban traffic management systems. This dissertation contributes to advancing understanding of the potential benefits and challenges associated with integrating the individual scheduling and innovative traffic management concepts into urban transportation systems, and proposing a way, as a dual perspective of traffic control, for more sustainable, efficient, and safe urban mobility solutions with the intelligent transportation system.