A number of road infrastructure elements, such as flexible barriers and roundabouts, have been identified and promoted as Safe System solutions due to their capacity to minimise death and serious injury.
But these elements do not always achieve the desired Safe System outcomes for all road users.
Last week Austroads published a report summarising the findings from the first of a three-year study which is reviewing the safety performance of road infrastructure identified as Safe System solutions.
The aim of the first year was to identify solutions and then establish how closely they fit the vision’s objective of zero death and serious injury.
Five infrastructure solutions were prioritised for investigation:
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traffic signals
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roundabouts
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flexible median barriers on divided roads
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flexible median barriers on undivided roads
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flexible roadside barriers.
The study found that traffic signals, which were identified early as an aspirational Safe System solution, performed well below the Safe System ideal of no fatal and serious injuries. An average casualty crash reduction of 30% was identified but no evidence was found that traffic signals reduced severe injury crashes. Crash data analysis showed that severe crashes involving opposing-turning, adjacent-direction, same-direction and pedestrian movements were the leading safety problems.
Similar investigations for roundabouts showed them to be particularly effective in reducing severe injury crashes and in particular fatal crashes. The severe crash rate was shown to be half that of traffic signals. Crash data analysis indicated that further investigations should focus on severe crashes involving: two-wheeled road users, adjacent-direction, off-path on straight and same-direction crashes.
Preliminary investigation of flexible barriers showed that they reduced targeted severe crashes by approximately 60%. Continuous application of flexible barriers was found to be important for increasing effectiveness, achieving up to 90% reduction in targeted casualty crashes. Overall, flexible barriers were shown to result in a very low likelihood of severe crashes, approaching the objectives of the Safe System. Further research could focus on heavy vehicle performance, roadside applications, installation and maintenance issues.
Future project work, which will be managed by the Austroads Safety Program, will identify ways to improve the selection, application and management of these solutions, so that their safety performance is brought closer to the Safe System vision.
Download: Improving the Performance of Safe System Infrastructure: Stage 1 Interim Report
