GUARDRAIL END-TYPES, VEHICLE WEIGHTS, AND ACCIDENT SEVERITIES

A study of guardrail end accidents on the Oklahoma State Highway Syste m (1988-91) examined the severity of exposed and turned-down guardrail end accidents in relation to the type of end, vehicle weight, and veh icle rolling and/or vaulting. The data showed that lightweight vehicle s and turned-down ends were associated with increased rolling and/or v aulting. Rolling and/or vaulting was associated with increased acciden t severity. A direct interaction among end-type, vehicle weight, and a ccident severity was not present; however, the interaction among end-t ype, vehicle weight, and rolling/vaulting was statistically significan t. In terms of the resulting injury and death, the overall performance of the turned-down ends was no better than the exposed ends that they had replaced.