Meta-Analysis of the Risk of Fatal and Incapacitating Injury in Tangent W-Beam Guardrail Terminal Collisions

A number of studies have been performed in recent years examining the injury outcome of guardrail terminal crashes using police reported crash data. Fatal and incapacitating injuries are rare in guardrail terminal crashes so collecting a sample of data with sufficient cases to make statistically significant conclusions can be difficult. A meta-analysis of previous similar studies allows for the consideration of the difference in crash outcome between terminals types. This paper describes a meta-analysis of ten studies to examine the differences in the probability of observing a fatal or incapacitating injury in a crash with a tangent w-beam guardrail terminal. This study found that there are effect size differences between the three most common tangent guardrail terminals: the ET Plus, the ET-2000, and the SKT. The ET Plus was consistently found to be the tangent terminal with the lowest risk of a fatal or incapacitating injury.