Motivation, and Fatigue-Related Impairments in Simulated Driving

The effect of a motivational manipulation in reducing fatigue-related impairments in simulated driving performance was examined. Drivers performed both a fatiguing drive and a control drive. The motivational manipulation, a driving skill assessment instruction, appeared in early and late stages of both drives. Lateral control of the vehicle was assessed on straight and curved road sections early and late during the assessment instruction in both drives. The results indicate that the instruction only affected straight-road driving in the later part of both drives. During the later part of the control drive, the instruction produced a performance improvement only while the instruction was actually presented. In the fatigue drive, performance continued to improve even after cessation of the instruction, converging to the level of control drive performance. Fatigued drivers remain capable of increasing task effort in response to a motivating instruction, but fatigue may impair the ability to synchronize effort with changing task demands.