A literature review was conducted which concentrated on identifying psychological theories and experimental evidence relevant to speed perception and road features that might affect drivers' judgements of speed limits and safe travel speed. This included information on the effect of task / cognitive load, utility, improved information on the posted speed, driver stress, perceptual illusions, enhancing perceived danger, adaptation effects, self-explaining roads, expectation effects and the effect of beautiful surroundings. The underlying hypothesised mechanisms for these effects were not always clear, and in many cases alternative mechanisms may be proposed which sometimes predicted different outcomes for the effect on driving speed. Women, particularly older women were likely to respond to the initiatives listed above whereas those drivers considered most likely to speed, such as young drivers, company car drivers and drivers on long journeys were least likely to respond. Potential design characteristics for use in sketches in discussion groups in later stages of the project were identified.
Abstract