Beijing Expressway Traffic Flow Detection System is one of the main support systems for intelligent traffic management in Beijing. It uses traffic flow detectors distributed on urban expressways and tie lines to transmit test data back to system data at set time intervals. The center, after pre-processing, stores the valid data in the system database, and provides the traffic management department with real-time road traffic conditions, traffic information statistics, inquiries, and basic data for leadership decision-making, management planning, and expressway traffic control. At the same time, the system sends data to other application systems through a dedicated interface, realizing the display of road condition information in real time on the command and dispatch system of the Public Security Traffic Management Bureau of the Beijing Public Security Bureau, and also through various means (such as outdoor display, television, radio, The Internet, etc.) publish road condition information to social traffic participants in real time. Through the release of real-time traffic information, the route is induced to the vehicle, the travel time of the traveler is shortened, the traffic congestion is alleviated, and the traffic flow distribution is balanced.