Abstract: Objective To study the characteristics and biomechanical mechanism of riding injuries involving bicycles collided by motor vehicles. Methods The real traffic accident cases of bicycles collided by motor vehicles, including the information of scenes, bicycles, motor vehicles, rider wounds and traffic directions, were collected. Retrospective method was used to study these riding injuries. In addition, typical cases were selected to simulate traffic accident courses with computer simulation software, and the dynamic data like acceleration, force, moment were extracted to compare with those in the real cases. Results There were no difference of occurring frequency between cases with or without riding injuries, as well as between one-side-collision and front-or back-collision. The riding injuries seemed less in accidents involving large-scale vehicles. The frequency of riding injuries increased with vehicle speed. The wound location was low on collision side and high on opposite. Conclusion Analysis of riding injury characteristic in traffic accidents and their biomechanical mechanism would be helpful for estimation of traffic manner.

Key words: riding injury, traffic manner, bicycle, computer simulation