| In intelligent transportation systems, one is faced with two crucial problems: traffic safety and traffic efficiency. Although much effort has been devoted to this area, many issues still remain unsolved, this dissertation presents a few attempts towards this topic by studying different vehicle operation control policies and traffic management strategies using a hierarchical hybrid system framework.; We first construct a hierarchical architecture of hybrid system for a single vehicle where the continuous time plant (vehicle dynamics) is supervised by the discrete-state controller, which is developed in a two-tier discrete event system. We then address the multiple vehicles cooperation problems by introducing an additional layer into the discrete event system that indicates the cooperation control tasks.; By employing the hierarchical hybrid system model, we develop microscopic traffic simulators that make it possible to analyze, test and evaluate different vehicle operation control policies and traffic management strategies.; We present an intersection collision mitigation approach, due to the practical relevance, we further design an inter-vehicle communication based three-level intersection warning system. Performance evaluation is presented using the traffic simulator which also mimic driver response and acceptability for alerts. Wireless communication based driver assistance systems are proposed to increase the traffic efficiency simultaneously decrease traffic accidents. System performance illustrates the effectiveness of wireless communication in intelligent vehicle applications and the proof-of-concept of technology availability. |
