Driving under the influence (DUI) of alcohol continues to be a major contributor in traffic fatalities. There is growing evidence for heightened trait impulsivity in DUI offenders, but little is known about how impulsivity could interact with alcohol intoxication in a manner that would increase the likelihood of driving while intoxicated. This placebo-controlled study examined the acute effects of 0.65g/kg alcohol on 2 facets of impulsivity (impulsive choice and response inhibition), simulated risky driving behavior, and subjective intoxication in a group of 20 DUI offenders and 20 control drivers with no history of DUI. It was predicted that compared with controls, DUI offenders would self-report greater impulsivity, and display greater impulsive choice and driver risk taking, particularly in response to alcohol. Results showed that alcohol impaired drivers' inhibitory control and increased their impulsive choice behavior and risky driving behavior. Alcohol selectively increased impulsive choice of DUI offenders, as control drivers showed no alcohol-induced increase in their impulsive choices. Results also showed that, compared with controls, offenders reported feeling less intoxicated and were more willing to drive after drinking. Laboratory studies are beginning to show that DUI offenders differ from nonoffenders in their acute responses to alcohol. This study identified two alcohol response characteristics of DUI offenders that indicate their lack of risk awareness during intoxication: heightened impulsivity and reduced subjective intoxication. Strategies and treatments to alter these response characteristics in DUI offenders could enhance their risk awareness during the intoxicated state and possibly reduce risk of DUI recidivism. (PsycInfo Database Record (c) 2020 APA, all rights reserved).