The speed of a vehicle should be entirely under the control of the driver. Proceeding at a speed that is excessive in view of the traffic conditions is a common contributory cause of accidents.
A Dutch study has shown that reducing the speed limit by 10 percent leads to a 50 percent drop in accidents. A report by the European Transport Safety Council includes a rough calculation that a speed reduction of just 5 kph could save 11,000 lives in the EU and prevent 180,000 injuries per year.
There is no statistical evidence that directly links higher speed with increased fatalities. In 1986, when the speed limit on highways throughout the the United States was 55 miles per hour, the national fatality rate was 2.5 deaths per 100 million vehicle miles. In 1994 the fatality rate was 1.7 deaths per 100 million vehicle miles, although the speed limit had been raised to 65 miles per hour. Improper turns, poor signaling, and drunken driving are the primary causes of highway deaths, not speed.