Alcohol Impairment Detection by the Phystester - Evaluation Program Summary

The Phystester, an ignition interlock system based on a predriving performance test, is evaluated. Results and observations from programs conducted by General Motors and other independent organizations are analyzed. The sensitivity of the psychomotor task offered by the Phystester to blood alcohol concentration, performance asymptoticity through distributed training, age, intelligence, drinking habits, sex, and digital dexterity is quantified.

Performance on the Phystester task is shown to be significantly correlated with blood alcohol concentration and with performance on simulated driving tasks. The Phystester is shown to be capable of discriminating between sober and intoxicated individuals, the intoxicated rejection rate being dependent on the magnitude of the acceptable sober rejection rate.