To effectively evaluate the traffic safety risk of urban expressways in real time and ensure their traffic safety and smoothness, a real-time evaluation method of vehicle conflict risk of an urban expressway based on smartphone GPS data was proposed. We screened and processed smartphone GPS data to obtain vehicle behavior data, including acceleration and angular acceleration, and road state data, including average vehicle speed. Urban expressways were divided into four categories, closed straight section, closed curve section, vehicle entry section, and vehicle exit section; the evaluation indexes of abnormal vehicle behavior were established. Based on the improved entropy weight method, the vehicle conflict risk entropy was established to distribute the weight of different types of abnormal behaviors of vehicles. The evaluation system of vehicle conflict risk entropy was applied to the vehicle behavior data. Urban Expressways with more abnormal vehicle behavior were obtained to evaluate the risk of vehicle conflict in real time. The results showed that the easily obtained smartphone GPS data may be effectively used to analyze the abnormal behavior of vehicles, identify vehicle conflict risk points hidden in urban expressways in real time to provide effective methods for batch and dynamic real-time evaluations of vehicle conflict risks on urban expressways, and improve the traffic safety service level of urban expressways.
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