A review of warrants for traffic barriers in divided carriageway medians

Nash, Lachlan (2015) A review of warrants for traffic barriers in divided carriageway medians. [USQ Project]


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The prevention of head on crashes is one of the major concerns for highway safety, especially on high-speed rural roads. Head-on crashes are typically caused by errant vehicles crossing the median and colliding with oncoming vehicles. Due to the high speed of the colliding vehicles on major rural highways, cross median crashes can result in severe damage and fatalities. Median barriers are designed to prevent such events by safely redirecting the errant vehicles. Various types of barriers have been developed over the years including rigid, semi-rigid, and flexible systems.

This project has reviewed relevant Australian and international guidelines, standards, and literature in order to identify and attempt to quantify all significant risk factors contributing to cross median crashes on high-speed divided carriageways. The literature review provided an extensive review of the existing guidelines. The consistency could not be relied on as the designer’s professional judgement is necessary to consider the hazards. The presence of individual judgement will result in some inconsistency of application of the guidelines. The questionnaire indicated some inconsistencies in the selection of median barriers on high- speed divided carriageways. It was found that professional judgement results in some inconsistency of application. This paper proposes to multiply individual risk factors to widen the envelope of circumstance where the median barrier is considered mandatory.

The proposed revised guidelines were applied to the two case study sites on the recently constructed Pacific Highway, North of Coffs Harbour. The Moonee Interchange site was found to just outside of the revised mandatory envelope which may possibly still warrant a median barrier. The Graham Drive site was found to be within the revised envelope. Therefore a median barrier is warranted at this site, which reflects the views of some experienced road designers.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Civil)
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Drysdale, Trevor
Date Deposited: 07 Jun 2016 05:06
Last Modified: 29 Jul 2020 00:33
Uncontrolled Keywords: warrants, traffic barriers, divided carriageway medians, median crashes, high-speed divided highway, median barriers, road design
Fields of Research (2008): 09 Engineering > 0905 Civil Engineering > 090599 Civil Engineering not elsewhere classified
Fields of Research (2020): 40 ENGINEERING > 4005 Civil engineering > 400599 Civil engineering not elsewhere classified
URI: https://sear.unisq.edu.au/id/eprint/29292

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