The link between vehicle speed and accident risk is explored in this lecture. Higher speeds markedly increase the frequency of collisions and when a collision occurs higher speeds increase the risk of injury or fatality. 41 000 poeple die every year on Europe's roads at a cost of around 160 billion Euros each year. The introduction and lowering of speed limits reduces deaths from accidents. Studies of changes to speed limits show that a decrease in the speed limit reduces the frequency of accidents and an increase in the speed limit increases the frequency of accidents. Risk also increases rapidly where a driver chooses to drive at a speed greater than that of other drivers on the same section of road. This increase in risk is similar to that of a driver who has been drinking alcohol. The risk generated by extra speed depends on the type of road and is highest on congested town roads. Reducing the speed of the fastest drivers is considered the most efficient way to cut accidents. Traffic calming in towns typically saves 50% of accidents for a 15kph reduction in average speed. Greater reductions are achieved in the vicinity of speed cameras. For collisions involving vehicle occupants speed changes on collision of 40kph or more, death or serious injury is almost certain whereas for a speed change of 8kph or less there is a greater than 80% chance of escaping death or serious injury. The potential for reducing speed related accidents in Europe is discussed. A 10-15% reduction is considered easily achievable.
Samenvatting