Harmful events in guardrail crashes



Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Civil and Environmental Engineering

Committee Chair

Ronald Eck.


While guardrails are intended to reduce the severity of ran-off-road crashes, even the best designs installed in the most appropriate locations cannot eliminate all serious injuries and fatalities associated with guardrail crashes. The performance of guardrails has been examined through controlled crash tests for the past 30 years. These tests however, could not replicate real world crash conditions and provide data on injury distributions and harmful events in guardrail-related accidents.;Recognizing these limitations, reported guardrail accidents from Highway Safety Information System (HSIS) databases were examined. Data analysis was done using two-way and three-way contingency crosstabulations. Statistical significance of the study results was checked using Chi-square tests.;Analysis of guardrail-related accidents showed that secondary harmful events increased driver injury severity in guardrail face-related collisions. In accidents involving guardrail end, guardrail end was the cause of high injury severity compared to that contributed by the secondary harmful events. It was also found that a change in standard heights established by AASHTO for guardrail face types "W-Beam with block out" and "2 Rail W-Beam with top rail block out and bottom rail with no block out" is suggested. Study based on additional data from more states is needed to substantiate these results.

This document is currently not available here.