A large number of crash prediction models have been developed in New Zealand and Australia, particularly the former, for different road elements and for different speed limits. These models provide an insight into crash causing mechanisms, which can in turn assist engineers in diagnosing safety problems. In conjunction with other road safety research (for example, results of `before and after studies) they can also be used to predict the change in crashes that might result from an engineering improvement, whether good or bad. The modeling methods used in New Zealand are based on best practice overseas, from the UK, Canada and the USA, with some local enhancements. An overview of the statistical methods used by Wood and Turner are outlined in this paper. The research to date has produced a number of interesting and thought provoking outcomes including the `safety-in-numbers effect for cyclists and pedestrians and that reducing visibility canlead to safety gains at roundabouts. Many other findings from the down-under research are outlined in the paper.
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