Investigating the relationship between crash severity, traffic barrier type, and vehicle type in crashes involving traffic barrier

Roadside safety is one of the important components of highway systems due to its considerable rate of high-severity crashes. Traffic barriers play a key role in reducing the crash severity and saving more lives on roadsides but choosing an inappropriate traffic barrier could decrease traffic barriers' efficiency. This paper investigated the variables affecting crash severity in different traffic barrier types (cable, guardrail, and rigid) and vehicle types (truck, and non-truck). For this purpose, an ordinal logistic regression approach was conducted on the crash data collected between 2007 and 2016 in Wyoming. According to the results, different traffic barrier types show different relationships to crash severity based on posted speed limit at the site. In guardrail segments, a high-severity crash is more likely when the posted speed limit is more than 55 mph; however, cable barrier crashes were less severe in high-speed limit (>55 mph) areas. While light vehicles were more vulnerable to crashes hitting rigid barriers, no significant difference was found between performances of cable and rigid barriers in terms of truck crash severity. The analytical models proposed in this study would make a clear view for designers and decision-makers in selecting the most appropriate traffic barrier. Also, the effective factors introduced in each model could be used to rank the risk posed by existing traffic barrier segments based on traffic barrier type, truck volume percentage, and other highway characteristics. (C) 2019 Periodical Offices of Chang'an University. Publishing services by Elsevier B.V. on behalf of Owner.