Predicting future performance of roads: keeping the balance

Road Infrastructure Safety Assessment (RISA) involves comparing a route with a baseline road type and recording differences in infrastructure items for which there are known accident relationships. Two indicators of safety result from this comparison: risk and score. Risk is independent of traffic volume, terrain, and road type effects. It measures the relative risk on the assessed road compared to a baseline road of that type. This is a measure of how well the road authority is managing its particular road assets from a safety perspective. To allow comparative measures to be made across road types, the risk indicator is scaled to reflect the route context. Score is the risk indicator scaled by factors for road type, terrain, and traffic volume. Several field trials on low volume rural roads have tested the practicability of RISA. The indicators have been compared with accident rates and assessor subjective ratings of the routes assessed. The comparisons show that RISA relates more strongly to the accident history than the purely subjective assessor rating. At this early stage, the sampling process is not refined to ensure that the sample is reflective of a road network, and that the number of routes assessed is enough to be able to generate a 'score' for an entire road network. This means that route scores cannot yet be combined, allowing for comparisons between road networks.


  • English

Media Info

  • Pagination: 16p

Subject/Index Terms

Filing Info

  • Accession Number: 01388008
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Aug 23 2012 12:34AM