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Recent researchers have suggested that the combination of horizontal curves or “bendiness ” of a length of road contributes to traffic crash occurrence. A previous study of New Zealand fatal crashes using an aggregated approach found no significant correlation between crash occurrence and road bendiness for rural roads but a minor correlation for urban roads. This thesis further explores the effect of road bendiness on traffic crash occurrence in New Zealand by developing a method more suited to traffic engineering. The method involves Geographical Information Systems (GIS) firstly to process data and secondly to calculate bendiness values. The following bendiness measures: bend density, detour ratio, cumulative angle, mean angle and standard deviation of angles; are applied to “influence areas ” surrounding crash and comparison sites. The method then dictates that some form of statistical analysis should be performed to distinguish between the bendiness of crash and comparison sites, while accounting for other influencing factors. Binary logistic regression is recommended