A wireless traffic information collection system in Beijing urban freeways

The importance of the traffic information collection system (TICS) in traffic control systems of urban freeways is analyzed. The advantages and disadvantages of some types of traffic detectors and data transmission methods are compared. For current TICS, wireless data transmission is suggested. In view of factors such as work principle, transmitting speed, and cost, the CDPD (Cellular Digital Packet Data) network is selected to transmit the traffic data. According to experimental results about the accuracy of RTMS (Remote Transportation Microwave Sensors) and data transmission experiments in Beijing freeways, the suggested scheme using RTMS and CPPD to compose TICS is feasible. Furthermore, the system structure and functional description of this wireless TICS are given.