Emerging Crash Trend Analysis

The identification and treatment of ?black spots? or hazardous road locations is a core business activity for road authorities. Evaluation of the resulting black spot treatment programs has revealed high returns on investment. Tools used for the identification of black spots include crash frequency (crashes per site or per km), crash rate (crashes per vehicle km travelled) or relative severity index (the aggregate of crash type costs). Australian road authorities, based upon data collected over a 5-year period, use a combination of these tools.
Experience has shown that clusters of crashes can develop over a relatively short time of one to two years. Under such circumstances, the use of the 5 year crash data analysis period would mask the seriousness of the problem and resulting in the late discovery of the site for treatment. This prompted the need to investigate and develop a means with which to provide early warning of emerging high crash locations. The Department of Main Roads and Queensland Transport have developed a methodology called Interpretive Modelling, which
compares a suite of five crash indicators, over three different time periods (short, medium and
long term), using a rolling segmentation along the road to ensure that no road location is overlooked.
Experience to date with the application of the model has confirmed that it is an effective means of monitoring emerging crash trends.