An approach to making bend treatments (signing and marking) consistent on a rural route was evaluated using behavioural data. Risk scores were assigned to bends on the A377 in Devon, on the basis of geometric and cross-fall information from the SCANNER road survey system, and collision data. Bends with tighter radii, low cross-fall values, and more collisions during a defined period, were assigned higher risk scores. A sample of drivers who regularly use the A377 drove a section of the route with 25 bends of varying risk score. The drives were managed by an accompanying driving instructor who attempted to ensure that drivers were free to choose their own speeds throughout. Mean speeds driven through the bends were negatively correlated (moderately to strongly) with risk score, suggesting that the risk scores possessed validity with respect to real driving behaviour (i.e. drivers moderated their speed in a way that suggests they are sensitive to the risk/difficulty of bends, as represented by the risk score). A short questionnaire study elicited speed estimates from drivers in response to picture mock-ups showing different levels of treatments on bends, corresponding to a six-level hierarchy of signing and marking. This showed that drivers lowered their speed estimates as the level of treatment depicted increased. The findings are discussed in relation to the use of the general approach being taken on the A377, and how it might apply to assigning risk, and treatment options, on other rural roads.

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