Vehicle speed plays an important role in accident identification nowadays, and the traditional method of vehicle speed reproduction is constrained by many external conditions. Due to the popularization of the event data recording system (EDR), this paper explores a new way of thinking about vehicle speed reproduction. This paper takes a collision accident between a car equipped with EDR and a motorcycle as an example, according to the degree of deformation of the vehicle on the map of the accident scene, it is determined to be a completely inelastic collision collision model, and utilizing the characteristics of the model that the two vehicles share the same speed at the end of the collision instant, we read the transverse and longitudinal velocities at the collision instant of the sedan as well as after the share of speed from the EDR equipped with the sedan and combine them with the law of momentum conservation to conduct a vector analysis of the speeds of the two vehicles at the moment of the collision. Combined with the law of conservation of momentum, the vector analysis of the speed of the two vehicles at the moment of collision is carried out, and then the vector speed of the motorcycle at the moment of collision is derived. Compared with the traditional method of speed reproduction, this method does not need to consider the physical evidence at the scene, the traces, and the angle of collision at the moment of collision between the two vehicles.