Alcohol influences on driving-related behavior: A critical review of laboratory studies of neurophysiological, neuromuscular, and sensory activity

Do alcohol influences upon performance and laboratory tasks had any valid transfer to real-world driving behavior? Laboratory studies of basic psychophysiological functions assumedly relevant for on the road driving performance were reviewed critically in terms of susceptibility to alcohol influences and individual differences. Understanding alcohol influences upon more complex behaviors (perception, attention, or even driving performance) can be facilitated by developing a relevant neurophysiological model; two important, interrelated issues for such a model were reviewed: (a) the actual site of the alcohol effects in the nervous system, and be () the apparent biphasic effect of alcohol. Neuromuscular aspects: standing steadiness is a sensitive behavioral indicator of alcohol intoxication, but its validity for driving impairment is not yet conclusively established at blood alcohol concentrations (BAC) from 0.08% to 0.15%. Sensory activity: six reviewed aspects of vision or arranged in order of decreasing susceptibility to low and medium BACs: (a) dynamic visual acuity, (b) adaption of brightness sensitivity, (c), critical flicker fusion, (d) static visual acuity, (e) glare resistance and recovery, and (f) visual field. Only the first three aspects showed significant impairment at medium BACs. Methodological issues: interrelations of variability and validity were discussed. Alcohol increases variability in many physiological and psychological response measures, even when the means were not significantly changed. Thus, are there unequivocally valid indicators of alcohol impairment which can be used to specify the criteria for impairment?