Sixteen clinically normal individuals drove in an optical driving simulator in both a non-alcohol and an alcohol condition. In both the 0 mg% (.00%) and the 90 mg% (.09%) blood alcohol level conditions, each subject was given 60 trials in which he was required to make and execute a decision to pass or to continue following a lead car. Times available to safely complete a pass and vehicle speeds were presented in a random manner.

During the alcohol condition, subjects not only attempted and completed significantly more passes but also experienced more accidents. Lateral control of the vehicle was significantly changed with increased deviation from the center track being exhibited when subjects performed under the alcohol condition. Mean decision-reaction times increased under alcohol as did error scores on a test of eye-hand coordination.

Scores of equivalent forms of the Columbia Driver Judgment Test given during non-alcohol and alcohol condition were not only significantly different but also showed a significant