Identifying the relationship between traffic speed and accident risk is a difficult task, particularly in urban areas where both traffic speed and accidents are affected by the varied road environment. This paper describes a statistical investigation based on speed data gathered from 100 urban link roads of UK and their corresponding traffic flows, road geometry and accident data. At a gross level, accident rates are seen to decline with increasing speed, but this is because accidents are positively related to vehicle flows, pedestrian activities and road features. However, analysis based on a categorisation of different road types shows that the accident frequency (accidents per year) on a link road is positively (accidents per year) on a link road is positively related to the mean speed and its coefficient of variation. (A)
Samenvatting