A. C. Stein and R. W. Allen, The Use of In-Vehicle Detectors to Reduce Impaired Driving Trips, presented at International Congress Exposition, Detroit, MI, Feb. 24-28, 1986. (SAE 860360, STI-P-383)For almost twenty years, researchers have attempted to develop an in-vehicle system which would prevent an impaired driver from operating his or her motor vehicle. These systems have ranged from breath testers to psychomotor tests, and have prevented operation of the vehicle by such methods as preventing the vehicle from starting or alerting drivers, and the police through alarm systems.This paper discusses the background leading to an in-vehicle system which was built and tested. We also discuss the system and its components, and present the results of two tests involving convicted drunk drivers. While the primary purpose of this project was to determine the feasibility of this type of system, the results of the two tests show promise for the reduction of impaired driving trips.

R. H. Klein and H. R. Jex, Effects of Alcohol on a Critical Tracking Task, Journal of Studies on Alcohol, Vol. 36, No. 1, pp. 11-20, 1975. (STI-P-143A)Performance on a Critical Tracking Task (CTT) decreased significantly as blood alcohol levels increased.The purpose of this experiment was to explore the effectiveness of the critical tracking task (CTT), an unstable compensatory tracking task, in discriminating intoxicated from sober subjects. Interest in this issue stems from the need to develop a simple, relatively rapid and effective psychomotor task which could be used to prevent drunken drivers from starting their automobiles.Typical tracking tests have been relatively insensitive to alcohol. Pursuit tasks have been somewhat more effective than compensatory tasks; however, the variations in method of presentation, manipulation and scoring criterion have led to variability in the results. There is, however, a considerable amount of experimental evidence which indicates that the CTT, a closed-loop compensatory tracking task in which the dynamics of the controlled element are inherently unstable, provides a sensitive measure of the operator's effective time delay and excess workload capacity. Consequently, we anticipated that the CTT would also be sensitive to the effects of alcohol.

R. W. Allen, A. C. Stein, and H. R. Jex, Detecting Human Operator Impairment with a Psychomotor Task, presented at 17th Annual Conference on Manual Control, Los Angeles, CA, June 1981. (STI-P-286)Psychomotor tasks have long been used as instruments for measuring human operator behavior and have often been proposed as selection and training devices. This paper discusses the application of one such test, the Critical-instability Tracking Test (CTT, often called the Critical Task), in the detection of alcohol impaired human operators. The validity of the CTT as a measure of human operator performance and its sensitivity to alcohol impairment has previously been established. The current work to be presented here concerns the detection problem wherein statistical decision theory is used to optimize the test's ability to discriminate impaired operators in the face of inherent variability in human performance.Testing strategy is discussed including setting performance criteria levels and determining the number of attempts permitted in order to pass the test. Also, the task's ability to detect operator impairment is compared to performance measures obtained in a driving simulator.