A CRITICAL TRACKING TASK AS AN ALCOHOL INTERLOCK SYSTEM 730095

A compensatory tracking task (The Critical Tracking Task) requiring the operator to stabilize the output of an unstable system whose level of instability increases monotonically up to the critical point of loss of control is evaluated for its potential to discriminate between sober and intoxicated performances.

Quantification of the results obtained in the laboratory controlled environment shows a great deal of promise, indicating that intoxicated failure rates of 50% for blood alcohol concentrations (BAC's) at or above 0.1% and 75% for BAC's at or above 0.14% can be attained with no sober failure rates.

A high initial rate of learning is observed, perhaps due to the very nature of the task whereby the operator is always pushed to his limit, and the scores approach a stable asymptote after approximately 50 trials. Finally, the implementation of the task as an ignition interlock system in the automobile environment is discussed. It is pointed out that lower critical performance limits are anticipated for the mechanized automotive units because of the introduction of larger hardware and neuromuscular lags. Whether such degradation in performance would reduce the effectiveness of the device or not will be determined in a continuing program involving a broader based sample of the driving population and performance correlations with both BAC's and driving proficiency.