The purpose of this study was to identify the characteristics of large-truck accidents on highway ramps in Virginia and to identify those variables that are of significant importance to the occurrence of large-truck accidents on highway ramps. The accident data for 1986 to 1989 were extracted from the computerised data files of the Virginia Department of Transportation (VDOT) for ramps on a random selection of interstate and primary routes. A major deficiency in the data compiled was the unavailability of AADTs and truck volumes on the ramps as VDOT does not regularly collect these data. The accident characteristics considered in the detailed analysis were type of collision, severity, major factor involved, highway type, and ramp type. Some findings were as follows: During the study period, accidents on interstate ramps were overrepresented on route I-95. This high occurrence of ramp accidents on route I-95 was not due to either the truck VMT or the number of interchanges located on the highway. A higher percentage of truck accidents on interstate highways occurred on exit ramps, whereas on primary highways, a greater percentage occurred on entry ramps. Sideswipe-same direction collisions were predominant at entry ramps on the interstate highway system. At the exit ramps on the interstate system, rear end and sideswipe-same direction collisions were predominant. All truck accidents involving two vehicles at ramps involved a nontruck as the other vehicle, and for a significant percentage of the rear-end collisions, the large trucks ran into other vehicles. On the primary highway system, rear end, angle, and sideswipe collisions were predominant at entry as well as exit ramps, although rear-end accidents represented the largest proportion. Contrary to general expectations, trucks were not significantly involved in noncollision types of accidents such as jackknifing, rollover, and run-off-the-road accidents. (Author/publisher)
Abstract