THE EFFECT OF SPEED LIMITS ON ROAD CASUALTIES

A study is reported in which the numbers of fatalities and casualties in 21 countries were regressed against their population, their number of vehicles and their posted urban and rural speed limits. It is demenstrated that speed limits, and particularly those posted for urban areas, have a considerable effect on safety. It is estimated that reducing the rural speed limit from 100 to 90 km/h and the urban limit from 60 to 50 km/h would reduce fatalities and casualties by up to one-third. The study showed that fatality rates of 11 industrialized European countries and of the U.S. could be closely estimated from their urban and rural speed limits alone. A method is described that makes it possible to analyze the relationship between safety and speed limits in a wide range of countries. It is concluded that speed limits are a powerful safety tool available to governments, but, as is demonstrated by the wide disparity in rural speed limits in different countries, the relationship between speed limits and safety is not yet fully recognized.