Measurement of traffic conflicts

Traditionally road accident statistics are used to assess the level of road safety and evaluate road safety programs. In some cases, the lack of good and reliable accident records have hampered proper analyses. A promising approach that overcomes this problem is the traffic conflict technique which relies on observations of critical traffic situations for safety analysis. However, despite the extent of work undertaken in traffic conflict research, there are still a number of issues on conflict measurement and application that have not been well understood by many safety analysts. This has resulted in a general lack of support for the wider application of the technique in safety analysis. This paper shows that one way of using the traffic conflict technique effectively is to ensure that conflicts are quantitatively defined, objectively measured and suitably applied. Before establishing the proposed framework for conflict analysis, the paper first discusses the problems and weaknesses often associated with conflict studies. Considerations for a conflict study based on the proposed approach are then presented and the case of an expressway merging is used to illustrate the method adopted.