Where an iRAP survey has been completed across a whole road network, it is possible to use the Star Ratings as part of the intelligence base for prioritisation. Typically, RSF recommends using both the Star Rating (where this is low it indicates there may be an aspect of the road layout or operation that could be improved) and Fatal and Serious Collision Density (where this is high this indicates that there may be good returns on investment).
National Highways used this approach for identification of the routes to be treated under the National Programme.
Where the Star Ratings are not available, RSF uses an indicative Benefit to Cost Ratio (BCR) generated through Crash Risk Mapping to identify priority routes for further survey and analysis.
