In the framework of the project for priority for slow traffic from the right this report discusses the relationships between driving speed, impact speed, and consequences of collisions between two-wheeled vehicles and cars. With the aid of a simple phase model of the collision process the problem is described on the level of the moped-rider or cyclist. There are two main relationships mentioned, namely those between the driving speed and impact speed and those between impact speed and outcome. Those main relationships and parts of them are studied in two ways; theoretically, with the aid of systematics from physics, and by means of data from accident studies. Conclusions from the theoretical part are affirmed by practice and relate to the incompatibility between two wheeled vehicles and motor vehicles. The result of a collision between these categories is almost always unfavourable for the moped rider or the cyclist, mainly caused by the great difference in the mass of the vehicle and the difference in the structural properties of the vehicles. Fatal two-wheeler accidents can be avoided when the impact speed of the motor vehicle is lower than 30 km/hour.
Abstract