Some important developments in methods of increasing the safety of road junctions are described in this paper. Over 60 percent of the personal-injury accidents that are reported on the roads of Great Britain take place within 20 m of a junction, therefore these methods have the potential to reduce the national accident toll substantially. Major Transport and Road Research Laboratory accident studies have now been conducted for several junction types (i.e. roundabouts, rural major-minor junctions, urban traffic signals). These have established relations between accident frequency, traffic and pedestrian flows, road geometry and other variables. The results are contributing to specific design improvements. This paper shows that in order to improve the safety performance of junctions of different types at a given location, it is necessary to employ accident predictive relations that take full account of the junction geometry and of traffic and pedestrian flows by manoeuvre. The results are considered briefly in the context of current needs and requirements for the safety components of traffic management appraisal. Planned TRRL work will develop equivalent predictive relationships for key components of the urban traffic environment. When it is complete it should be possible to appraise the safety performance of scheme options, and fully exploit the potential for casualty reduction.
Abstract