The influence of vehicle type on the estimation of velocity while driving.

Velocity production in the absence of speedometer information was investigated as a function of car size. In the first experiment three vehicles of different sizes were driven by 30 subjects; in the second experiment a different sample of 20 subjects used their own vehicles, which were classified into two size categories. In both experiments subjects were required to drive under conditions of normal and attenuated auditory feedback. The results indicated a greater production accuracy in small compared with large cars and a tendency for drivers of small cars to make greater use of auditory information. The results are discussed in the context of the relative contribution of different sensory channels to the subjective scale of speed.