With the aim of exploring the factors that underlie drivers' judgements about speed limits and appropriate operating speeds, drivers were presented with photographic sliders of normal traffic scenes and asked to say what they thought the average speed of the traffic would be. Two independent factors were manipulated in the scenes used, a land use factor which included recreational, industrial, commercial and residential environments, and a road configuration factor which included undivided two lane and four lane roads, and divided roads with narrow and wide medians. ANOVA showed that although both factors were significant, the interaction was much larger than the main effects. It was concluded that this technique was a viable means of investigation speed judgements, that the greatest discrepanties between estimated operating speeds and speed limit occurred on four lane undivided roads and divided roads with narrow medians, and that future work should attempt to relate estimated speds with actual speeds measured on-site.
Abstract