The report describes two experiments designed to investigate the effects of alcohol on driver decision making as opposed to driver control capability. The first experiment consisted of a laboratory study involving a complex, interactive driver simulator. The second study was a field validation experiment employing an instrumented car and interactive test course which duplicated many of driving simulator tasks and conditions. The purpose of the research was to determine whether alcohol affects the driver's willingness to accept risk, or whether alcohol merely deteriorates his perceptual and psychomotor properties, leading to unavoidable increases in risk taking that cannot be compensated for. The results of the two experiments were quite consistent. Risk taking increased in a dose response relationship with BAC (blood alcohol concentration) as measured by increased accidents and traffic tickets, and the accident results are consistent with real world epidemiological data. Decision making analysis indicated that the increased risk taking was caused by degraded perceptual and psychomotor capabilities, not increased acceptance of risk.
Abstract