The author emphasises that it is change in velocity that kills and injures and outlines how crash severity can be used to assess change in velocity during a collision. Test specifications are based on a single point, 30 mph flat barrier crash with all occupants injured. Accidents in the field are compared and show two interacting distributions - the skewed crash distribution of exposure and the distribution of tolerance to injury. To provide the best protection for the largest number of people is therefore complicated. The distance over which velocity change takes place and head trajectories are also considered. Cyclists, pedestrians and motor cyclists are found to be at more risk than car occupants and vehicle contact speed is of particular importance in level of injury. The author briefly outlines some ideas which could be applied to speed management policies including the use of speed zones, repeated signs, enforcement, a demerit system and the need to convince people that the policies chosen actually work and are worthwhile. For the covering abstract of the conference see IRRD 843582.
Abstract