SPEED AND HEAVY VEHICLE SAFETY

There are grounds to believe that the link between speed and safety outcomes may be even more critical for heavy vehicles than for light vehicles. Concern and action on heavy vehicle speeds has tended to focus on the small proportion of heavy vehicles that exceed posted speed limits by a substantial margin. These vehicles represent a significant safety hazard, but even speeding by a few km/h involves substantial additional risk. 'Low level' speeding is important to overall safety outcomes because it is far more common than extreme speeds. Extrapolation from available evidence suggests that total elimination of heavy vehicle speeding might prevent roughly one quarter of serious casualties involving a heavy vehicle. Heavy vehicle speed compliance is only one of the links between speed and heavy vehicle safety outcomes. The setting of speed limits and management of light vehicle speeds are the other important speed factors that will determine the number of serious "heavy vehicle" crashes in coming years. (a) For the covering entry of this conference, please see ITRD abstract no. E209724.