Project: Link Based Accident Models

Reference: H131

Last update: 20/10/2004 14:52:59


This research is reviewing accident models suitable for use in the National Transport Model (NTM), and the new TUBA/COBA programs, using links as the basic unit. It is needed because accident frequencies were last calculated some 10 years ago and may not reflect current accident values.


The most widely used models for accident numbers are the trend based data used within COBA. These either model links and junction accidents seperately, or use in an all-inclusive link-based estimate. This project is split into two phases:
1. The first phase which has been completed, reviewed existing accident models in Great Britain and developed accident rates which have been used in National Transport Model (NTM).
2. The second phase is examining accident rates by time of day and trend factors, by road type. This phase also examines child KSI proportion and trend factors, by road type.


TRL Limited
Crowthorne House, Nine Mile Ride, Wokingham, Berkshire, RG40 3GA
+44 (0)1344 773131

Contract details

Cost to the Department: £19,308.00

Actual start date: 10 July 2001

Actual completion date: 31 December 2003

Summary of results

  1. A series of accident rates by road types and by times of day was produced for use in the National Transport Model.