The rural speed limit and traffic accidents

Abstract

This investigation is a comprehensive examination of the relationship between rural speed limits and accidents. South African's road fatality rate is very high when compared to those of Western countries, and its urban and rural speed limits are above average. South African drivers are in favour of higher speed limits than are drivers from New Zealand, Finland and the USA. An analysis of twelve industrialized Western countries showed that their fatality rate could largely be explained in terms of their speed limits. Forty-eight speed limit changes in twelve countries are described, and three models relating the change in fatal, injury and total accidents with the change in mean speed have been developed. South Africa's accidents between 1972 and 1985 are analysed against a number of factors by multiple linear regression. The mean speed of rural traffic affects all categories of rural and urban accident; the urban speed limit affects all categories of urban accident and rural fatal end injury accidents. It is concluded that a change of speed on part of the road network affects accidents elsewhere on the network. It is estimated that the lower rural speed limits introduced between November 1973 and August 1984 saved 12 500 lives and 140 000 accidents. It is recommended that the urban and rural speed limits be reduced to 50 and 90 km/h respectively.