Rear-end accidents at signalized intersections are often considered as a normal occurrence in the USA. Some researchers even accept such results thinking that the installation of traffic signals reduces more severe accidents like right angle and left turn head on accidents, whereas it increases rear-end accidents. Traffic and Safety Engineers have accepted this almost as inevitable. The authors conducted a citywide analysis of three years (1988, 1989 and 1990) of traffic accident data for 103 signalized intersections in Grand Rapids, Michigan. This study also included reviewing roadway geometry and other features of the intersections. Particular attention was given to the intersections with a high density of driveways both at the approaches as well as at the far sides of the intersections. This research demonstrated that the high incidence of both near side and far side rearend accidents is primarily a function of clearance interval design and density of commercial driveways. The design of clearance intervals (yellow plus all red) is based on many factors. The variables used in this formula include approach speed, width of cross street, acceleration and deceleration characteristics. Sight distance and pavement condition are indirectly considered in the approach speed and acceleration and deceleration rates. This research included statistical comparisons of accidents at signalized intersections with adequately designed clearance intervals with low driveway density and inadequate clearance intervals with high driveway density. The results of this study point towards ways to mitigate high incidences of rear-end accidents at signalized intersections.
Samenvatting