Effective use of clear zones and barriers in a safe system's context
This paper describes an exploratory study that re-examined the use of clear zones as the preferred rural roadside treatment to address fixed object crashes, as compared to barrier treatments, within the context of a safe system's approach to road safety. Traditionally, a clear zone of up to nine metres is recommended on a straight section of road. A sample of crashes from the Centre for Automotive Safety Research (CASR) in-depth crash investigations in South Australia was analysed to determine the typical dynamics of vehicles in single vehicle run off road crashes, with a particular focus on the lateral departure distance and the departure angle of the vehicle. A number of these crashes were simulated using advanced computer techniques to determine the relative merits of clear zones and barrier protection. The relationship between the speed of the vehicle and its lateral distance from the edge of the road throughout the departure event was investigated. The merit of barrier protection was assessed by determining the barrier normal velocity at differing barrier protection offsets. Initial analyses showed that in crashes where no fixed object was struck, all vehicles travelled well beyond the nine metre clear zone, with several travelling over 20 metres laterally. Simulations suggest that adequate clear zones to ensure noninjurious impact speeds can not be provided in most situations. Roadside barrier protection in combination with narrower clear zones may provide the most cost effective way to treat rural roadsides to achieve a safe system.
- Record URL:
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Corporate Authors:
ARRB
Melbourne, Victoria Australia -
Authors:
- Doecke, S
- WOOLLEY, J E
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Conference:
- Australasian Road Safety Research Policing Education Conference, 2010
- Location: Canberra ACT, Australia
- Date: 2010-8-31 to 2010-9-3
- Publication Date: 2010-9
Language
- English
Media Info
- Pagination: 10p
- Monograph Title: Safe system: from knowledge to action: Road Safety Research, Policing and Education Conference 2010: 31 August-3 September 2010, National Convention Centre, Canberra, ACT: proceedings
Subject/Index Terms
- TRT Terms: Conferences; Crash analysis; Environment; Highway safety; Ran off road crashes; Roadside hazards
- Geographic Terms: South Australia
- ITRD Terms: 9150: Risk; 1653: Run off the road (accid); 2775: Rural road; 1686: Safety fence
- Subject Areas: Environment; I82: Accidents and Transport Infrastructure;
Filing Info
- Accession Number: 01332749
- Record Type: Publication
- Source Agency: ARRB
- Files: ITRD, ARRB, ATRI
- Created Date: Mar 15 2011 11:29AM