ARSRPE Conference Paper Database

World's Best Practice in the Use of Flexible Barrier Systems Along High-Speed Roads

Candappa, Nimmi

Road Environment


Run-off-road crashes represent, arguably, the largest single source of serious road trauma in Victoria and contribute significantly to the road toll in all states of Australia. In recent years, runoff-road crashes accounted for three to four of every ten fatalities, occurring both in metropolitan and rural Victoria. Single-vehicle crashes, on average, produce injuries of high severity due to the involvement of rigid roadside objects. Conventional treatments such as shoulder sealing, delineation and clear zones have had only limited success in reducing the extent and severity of run-off-road crashes. Such treatments tend to result in incremental improvements in safety rather than fundamental changes to injury and crash risks. More recently, flexible barriers (specifically Wire Rope Safety Barriers) have been used over long lengths of roadway, with great success. Flexible barriers deform and re-direct errant vehicles by absorbing the impact energy, thereby avoiding the severe outcomes associated with head-on collisions, crashes into rigid objects or rollovers. Although flexible barriers have already been installed at some sites, their use in Victoria is still in the early stages. Sweden, a world leader in road safety, has used flexible barriers to reduce the occurrence of fatalities on treated routes by up to 90%. This has been achieved through extensive use of flexible barriers and the introduction of the innovative "2+1" road configuration. Under this layout, flexible barriers are positioned along a three-lane undivided road providing alternate sections of two lanes in one direction, separated from the one lane in the opposing direction. Swedish research and practice indicate that a large number of crashes occur on a small percentage of the road network, implying that flexible barriers need only be installed on a minor proportion of the road network in order to effect a large reduction in the road toll. Flexible barriers, therefore, appear to offer a cost-effective and viable solution to this major source of road trauma. Public support for the barriers rose dramatically in Sweden within the first year of implementation. This research-based paper presents findings of world?s best practice in flexible barrier use and reports on opportunities to apply, in principle, the flexible barrier treatments employed in Sweden, along Victorian roads, in an attempt to substantially reduce the number of severe run-off-road and head-on crashes.