Slower vehicle speeds dramatically reduce injuries & deaths

Michael Paine has compiled much interesting research into the how vehicle speed affects the amount of collisions, injuries, and fatalites. A few excerpts:
Swedish research (Nilsson 1993) into speed limit changes throughout the developed world suggests a fourth power relationship between mean traffic speed and the proportion of fatal crashes. A 3% reduction in mean traffic speeds can produce a 12% reduction in fatal crashes.

The faster a motorist is travelling the less chance they have of avoiding a crash and the higher the impact speed if they do crash. This double whammy effect means that travelling at just 5km/h over the speed limit doubles the risk of being involved in a serious or fatal crash . . .

[S]tudies in the USA have shown that, in effect, every minute saved by travelling in excess of the speed limit results in a one minute loss in life expectancy across the community due to the increased risk of a fatal crash.
On another page he adds this tidbit:
At 20km/h [12MPH] 4% of collisions are fatal. This rises to 9% at 30km/h [18MPH], 25% at 40km/h [24MPH] 83% at 50km/h [30MPH] and, in effect, 100 % at 60km/h [36MPH].
Other relevant facts:
  • Pedestrians have represented 11-17 percent of all U.S. motor vehicle deaths since 1975.
  • In 2001, pedestrian deaths made up almost one- fourth of traffic deaths among 5-9 year-olds
  • In 2001, pedestrian deaths made up 16 percent of traffic deaths among people age 70 and older.
All this is relevant to the provision in the proposed highway safety legislation, supported by the resolution passed by the Missouri PTA, to set a statewide standard 20 MPH speed limit for school zones, and several provisions in the legislation helping to improve pedestrian safety.