Impact of Roadside Design Compliance and Hazard Offset on the Risk of Single-Vehicle, Run-Off-Road Crash Fatalities

Abstract

single-vehicle, run-off-road (sVROR) crashes account for a significant portion of all road-related injuries and fatalities worldwide. however, no previous study has examined to what extent roadside design guidelines have been applied, nor (and most importantly) whether having a compliant roadside design reduces the likelihood of fatal injury occurrence in sVROR crashes. thus, the objectives of this research are i) to examine the level of roadside design compliance within the studied area based on the selected benchmark and ii) to investigate whether roadside design compliance reduces the likelihood of fatal injury occurrence in sVROR crashes. Findings from this study are based on extensive crash and field data collected from 1,070 sVROR injury collisions and locations, respectively. the study shows that i) only 32 percent of the studied locations contained compliant design, and ii) barrier and discrete-obstacle lateral offsets larger than 6 and 12 meters, respectively, tended to lower fatality risk. the 12-meter clear-zone (cZ) width is larger than that recommended by previous research, which has based cZ width recommendations also on cost-benefit procedures and not just on fatality risk reduction.

Identification of Risk Factors Associated with Fatal Intersection Crashes and Assessment of the In-Service Safety Performance of Signalized Intersections and Roundabouts in Abu Dhabi

“…Many of these rollover events occurred after vehicles hit curbs. Previous studies showed that a significant portion of the roadside design adopted in the Emirate of Abu Dhabi is non-compliant to state-ofthe-art guidelines largely due to excessively high curbs [78], which may likely have contributed to vehicle instability, eventually resulting in rollovers; and (ix) crashes occurred at signalized intersections rather than at roundabouts. Indeed, the odds of fatal injury occurrence was found to be 1.8 times higher at signalized intersections as compared to roundabouts while controlling for the presence of access points, lighting condition, object struck, and seatbelt usage, though this finding is based on a p-value marginally higher than the widely used 0.10 threshold.…”