A very high proportion of road accidents occur at junctions. For example, in Sweden, about 25% of accidents on rural roads and over 50% of accidents on urban roads occur there. Many of these accidents are serious, and a high proportion of their casualties are pedestrians and cyclists. This article reports an international study of accidents at the following types of urban junction: (1) roundabouts; (2) signal-controlled junctions; and (3) three-way and four-way priority junctions with yield or stop control. Serious accidents are much more likely to occur at high speeds and in complex situations. That is why roundabouts and signal-controlled junctions are normally safer for drivers. The main objective of junction design is to reduce the number and severity of potential conflicts between different types of road users. Factors to be considered include human factors, physical elements, traffic considerations, economic factors, and vehicle emissions. One part of the study compared accident prediction models, developed in various countries, and determined how far those predicted values agreed with empirical results for those and other countries. The study recommended seven principles for designing safer major urban junctions, and proposed five areas for further research and development on urban junction safety.
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