The report examined the effectiveness of road safety engineering treatments. The treatments, which included the use of profile line marking, regulatory signs and median islands, were given a “Crash Reduction Factor” based on results from recent road safety studies.
It was developed to fill in the knowledge gaps as previous Austroads research identified that there is a lack of reliable information regarding the effectiveness of different road safety engineering treatments.
It found by changing partial control to fully controlled right-turns at traffic signals, installing roundabouts, and by adding barriers and signage at railway level crossings accidents were reduced by 70%. For pedestrians installing a pedestrian overpass reduces the chance of an accident by whopping 85%.
The report also showed the use of overt speed camera’s provided a crash reduction figure between 30-40% while reducing speed limits reduced risk up to 20%. It however showed increasing speeds, especially from 100 to 110kmh, increased the risk by 25%.
It also indicated the use of profile line markings (such as rumble strips) can reduce run off road crashes by as much as 40% and profile markings were also shown to reduce head-on collisions by 30% when used to mark the centreline of a road.
Sealing shoulders was found to have a crash reduction factor of 30%, with one of the individual Australian studies referenced in the report finding as much as a 60% reduction in crashes when an already existing shoulder is sealed.
The study also examined the effect of extending right-hand turning lanes, but was unable to draw a conclusion due to a lack of recent significant research in this area. Extending right-hand turning lanes ensures that heavy vehicles do not jut out into the traffic.
Regulatory signs were shown to have crash reduction factors of between 15 and 60 per cent, with the installation of four way stop signs at X intersections and the banning of U-turns the most effective options in reducing crash factors.
A full copy of the report can be viewed on the Austroads website.