Abstract: An analytic model of vehicle-bicyclist crash is developed based on in-depth accident investigations. The countermeasures for minimizing the brain injury risk of bicyclist are suggested through an improvement of vehicle frontal structure. The multi-body (MB) program MADYMO is used to reconstruct the real-world accidents for evaluating the analytic model and method. The frontal structure parameters of three common types of passenger vehicles (Sedan, SUV and MPV) are defined in this study, including bumper height, bumper protrusion, height of hood leading edge, hood length, hood angle, windscreen angle. Influences of velocity and frontal structure of vehicle on bicyclist brain injury are analyzed. Moreover, some feasible measures for protecting bicyclist brain traffic injury are discussed. The simulation results indicate that vehicle collision velocity has remarkable effect on severity of bicyclist brain injury. The design parameters, such as height of hood leading edge and bumper also affect the brain injury risk, especially for the sedan. Therefore the brain injury risk of bicyclist can be decreased by properly reducing the height of sedan’s bonnet leading edge and bumper

Key words: Accident reconstruction, Bicyclist, Brain traffic injury, Multi-body dynamics