Drivers were shown colour transparencies of normal traffic scenes and asked to estimate the speed limit, the speed they would adopt, and the average speed of the traffic in each scene. A set of 48 traffic scenes was assembled according to a factorial design, with four levels of road configuration, four levels of adjacent land use and three replications for each road configuration/ land use combination. Fifty per cent of respondents judged the speed to exceed the actual limit in 11 of the 48 cases. Estimates of the respondents' own operating speed corresponded closely to estimates of speed limits, while estimates of average speeds exceeded these by a consistent 5 km/h. Anova showed both factors to be significant, but the road configuration factor accounted for over three times as much of the variance as did the land use factor. The interaction between the two main factors, although significant, accounted for only a very small proportion of the variance. Further work is required to establish whether the distribution of speed estimates match speed distributions on site. If reasonable agreement is found, then it is suggested that the technique used in the experiment could be a useful way of estimating drivers' likely response to environmental changes designed to reduce operating speeds. (A) The ISBN of the microfiche version is 0-86910-276-1
Samenvatting