The results of a study sponsored by the federal highway administration and conducted at the texas transportation institute that examined the issue of rollovers caused by concrete safety-shaped barriers are presented. The study objectives were to determine the extent and severity of overturn collisions with concrete safety-shaped barriers, identify the causes of rollover of vehicles in impactswith concrete safety-shaped barriers, and identify potential countermeasures toreduce concrete safety-shaped barrier rollovers. The study approach consisted of a critical review of the literature, clinical and statistical analysis of accident data files, and computer simulation. The extent of the rollover problem on concrete safety-shaped barriers was found to be less than reported in previous literature. A number of impact conditions were identified from accident studies and confirmed by simulation as potential contributory factors to rollovers. Threealternative barrier shapes were evaluated as potential countermeasures: f-shape, constant slope, and vertical wall. Results of the evaluation indicate that thef-shaped barrier offers little performance improvement over the existing safetyshape. The vertical wall barrier offers the greatest reduction in rollover potential, but with the greatest increase in lateral accelerations. The constant sloped barrier may provide the best compromise solution. This paper appears in transportation research record no. 1258, Roadside safety 1990.
Abstract