There is considerable interest in many countries in the way in which their annual road accident casualty totals have developed. Thisleads inevitably to the question of how these totals are likely to change in the future. This paper assesses national data for Great Britain from 1949-1989 and forecasts the casualty total in the year 2000 by extrapolating the long-term decline in the rate of casualties per hundred million vehicle-kilometres. This forecast is conditionalon the traffic growth predicted by that year, but it is found that uncertainty over the casualty forecast derives more from the slight irregularities in the past decline in the casualty rate than from uncertainty over the traffic prediction. Despite the use of a forecasting method that is based on an unusually strong time-series model, there is still real uncertainty about forecasting casualties over a gap of only 11 years. (A) This paper was published in a special issueof Accient Analysis and Prevention entitled 'Theoretical models fortraffic safety' and for the covering abstract see IRRD 846002.
Abstract