Traffic Management

The aim of this project was to establish the effectiveness of key Local Area Traffic Management (LATM) treatment types in reducing traffic speeds and in reducing the risk of crashes on local roads in Australia. A review of recent literature (post-1995) was carried out for eleven key LATM treatment types. It produced typical speed reduction estimates at and/or between installed treatments. Crash reduction factors were also provided where available. Much of the information was based on overseas sources of varied quality. Additional local trials were recommended for nine of the eleven LATM treatment types to better understand the effect of the design on the speed reduction effectiveness, and hence, on crash risk. Two of these nine treatment types were chosen for such trials as part of the project. Speed profiles were collected at 14 local road roundabouts and at 9 mild centre blisters using inconspicuous laser gun profiling of free flowing vehicles. Geometric design information for each site was obtained from the local governments. For both treatment types, data analysis produced statistically significant relationships for calculation of the expected 85th percentile speed at the treatment given the radius of the maximum travel path through the treatment. Typical speed profiles and average zones of influence were also produced. Expected crash reduction factors were calculated for both treatment types. Also, the data showed that minimum design speed was not an adequate predictor of the operating speed at the treatments.