Relationships between off-road fixed-object accident rates and roadway elements of urban highways. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Run-off-road collision avoidance countermeasures using IVHS countermeasures. Task 3: report. Volume 2. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Over-embankment accidents on rural 2-lane conventional highways.

Mode of access: Internet.

Evaluation of a procedure for reducing vehicle-tree accidents. Final report.

Virginia Department of Transportation, Richmond

Safety aspects of roadside cross-section design. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.

Guardrail encroachment monitor - GEM. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.

Guardrail encroachment monitor - GEM. Summary report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.

Vehicle entrapment. Final report.

Federal Highway Administration, Washington, D.C.

Single vehicle roadway departure crashes: problem size assessment and statistical description.

Mode of access: Internet.

Embankment guardrail. Final report.

Mode of access: Internet.

Hazardous effects of highway features and roadside objects. Volume 1: literature review and methodology. Final report.

Federal Highway Administration, Washington, D.C.

Hazardous effects of highway features and roadside objects. Volume 2: findings. Final report.

Federal Highway Administration, Washington, D.C.

Examination of single vehicle roadway departure crashes and potential IVHS countermeasures. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Effect of clear zone widths on run-off-road crash outcomes

Current guidelines on clear zone selection and roadside hazard management adopt the US approach based on the likelihood of roadside encroachment by drivers. This approach is based on the available research conducted in the 1960s and 70s. Over time, questions have been raised regarding the robustness and applicability of this research in Australasia in 2010 and in the Safe System context. This paper presents a review of the fundamental research relating to selection of clear zones. Results of extensive rural highway statistical data modelling suggest that a significant proportion of run-off-road to the left casualty crashes occurs in clear zones exceeding 13 m. They also show that the risk of run-off-road to the left casualty crashes was 21% lower where clear zones exceeded 8 m when compared with clear zones in the 4 – 8 m range. The paper discusses a possible approach to selection of clear zones based on managing crash outcomes, rather than on the likelihood of roadside encroachment which is the basis for the current practice. It is expected that this approach would encourage selection of clear zones wider than 8 m when the combination of other road features suggests higher than average casualty crash risk.