This report concerns traffic accidents occurring during the 5 years, 1979-1983, at a sample of some 300 t-junctions on rural single carriageway roads subject to a speed limit of 50 mile/h or higher and covering 40 english counties. The objectives of the study were to investigate the frequency and character of the accidents in relation to traffic flow, geometric layout and other factors, such as traffic speed and gradient. The study examined in particular, the safety performance of three design features, ghost islands, merging and diverging lanes, and islands in the minor road. The study examined not only those accidents occurring within 20 m of the t-junction (the 'stats 19' definition of junction accidents) but also accidents up to 100 m from the junction. Multiple regression analysis was used to relate accident frequency at the junctions to a range of explanatory variables to provide a model for examining the effect of the geometric and other features. (Author/publisher)
Abstract