Analysis of the actual operational speed characteristics is an important method to evaluate the safety of freeway in operation period. However, long-term and full-space covered investigation about the actual vehicle operational speed is defective at present. In order to technically evaluate the safety of freeway by speed analysis, a vehicle speed survey method combining in-vehicle speed measurement and fixed radar speed measurement is proposed to obtain real vehicle’s speed data of freeway accident-prone sections. Aiming at the full-space speed covering accident-prone section, the method of field operational test with on-board sensors was proposed. By repeatedly cruising on the target road section, actual vehicle speed data of surrounding vehicles were obtained through the on-board sensor, which realizes the full coverage of the space. Aiming at the long-term data observation for accident-prone section, a fixed roadside radar base method was proposed to continuously observe vehicle trajectory and extract the speed of each vehicle, which achieves the full coverage in time. The comprehensive extraction method of operational speed proposed in this study takes into account the requirements of the full coverage of space and time. It provides a new vision for freeway speed characteristics analysis and evaluate the assessment.

CICTP;Safety evaluation;field operational test;in-vehicle senor;speed observation;speed characteristics