Establishing relationships between accidents and flows at urban priority road junctions

This papers explores the effects of traffic stream flows on accident potential at urban priority-controlled (i.e. unsignalised), four-arm junctions. Forty-three urban priority junctions were carefully selected so that other than flow parameters expected to influence accident potential have similar values at the junctions considered. Using traffic accident data for five-year time periods and the corresponding 24-hour flows, a new exposure index is proposed consisting of an expression of the flows of the junction's interacting traffic streams. The regression of this exposure index on the expected number of accidents per year at junctions of the type examined yields a quite satisfactory correlation coefficient, better than those achieved when other proposed indices are used.