ALCOHOL, TASK DEMANDS AND PERSONALITY AFFECT DRIVING: BEWARE THE INTERACTIONS

Two experiments conducted with an instrumented car on closed-course test tracks are summarized. Measures of driving accuracy and control use were obtained in a repeated measure design with subjects who were given controlled doses of alcohol to reach desired bac's. Driving accuracy measures included speed maintenance, pylon upsets, and stopping accuracy. Control use measures included steering wheel, accelerator, and brake pedal movements. Task demands and personality differences were measured to investigate the possible interaction of these variables with alcohol. Alcohol decreased driving accuracy and altered control use. Generally, alcohol increased control use activity, particularly for larger control movements rather than very fine control adjustments. These alcohol influences were found to interact with loading-task demands and personality differences. Results are discussed in terms of driving sets established by the experimental subjects, and in terms of driving priorities determined in part by task demands. (Author/TRRL)