Drivers' Characteristics in the Perception of a Lead Vehicle's Deceleration Level

Drivers' characteristics in the perception of a lead vehicle's deceleration level were investigated in the laboratory using film clips made from a vehicle following another vehicle in a car-following situation. To construct a scale of the perceived deceleration level, a magnitude estimation method was used and the relation between the perceived and the actual deceleration level was expressed in terms of Stevens' power law. The results showed that the drivers generally underestimated the lead vehicle's deceleration level and as the deceleration level increased, so did the amount of underestimation. The relation between the perceived and the actual deceleration level fitted to Stevens' power law very well (r2 =. 997), having the exponent of. 648. Finally, the visual cues used in perceiving the deceleration level of the lead vehicle and the devices that can aid the drivers are discussed.