Real-time Traffic Status Evaluation Method for Urban Cooperative Vehicle Infrastructure System

To guide traffic flow dynamically and alleviate traffic congestion, real-time traffic status evaluation methods can provide traffic management systems with quantifiable dynamic road network information. Owing to the time-varying characteristics of traffic networks and the subjectivity of the evaluation process, the accuracy of traditional evaluation methods has not been achieved. With the advantage of acquiring road information dynamically in an urban cooperative vehicle infrastructure system (CVIS), a novel real-time traffic status evaluation method using vehicle and infrastructure information fusion was proposed. First, a method for wireless interaction between connected vehicles and road side units was identified, and an improved data protocol was established to ensure the accuracy of real-time vehicle data. Second, the average travel time, average number of stops, and average stop time were selected as first-level evaluation indexes of a fuzzy comprehensive evaluation. Then, the first-level evaluation results calculated by the multi-operator were used to establish the second-level traffic state evaluation indexes, and the index weights were determined according to the analytic hierarchy process. Meanwhile, according to the simulation and experimental results, a variable membership rule for all levels of road parameters was established, which combined dynamic vehicle data with parameters of static road sections, and the final traffic evaluation scores were calculated. Finally, an actual urban CVIS system was developed to test the reliability of the real-time traffic status evaluation method. The experimental results show that the real-time evaluation scores were consistent with the corresponding trend of real traffic status, thus, accurately reflecting real-time traffic status in an urban CVIS. The proposed method improved the real-time capability and objectivity of the traffic status evaluation results; furthermore, it can be used to provide a theoretical basis for the application of a CVIS in guiding real-time traffic and alleviating urban traffic congestion. © 2019, Editorial Department of China Journal of Highway and Transport. All right reserved.