The effects of alcohol on driving-related sensorimotor performance across four times of day.
OBJECTIVE
The effect of alcohol on driving-related tracking tasks at four times of day was examined to address concerns that the legal driving alcohol threshold in New Zealand (80 mg/dl blood) may have greater effects during the early afternoon and early morning than during the evening and midmorning.


METHODS
A volunteer group of 16 male army personnel provided a homogenous sample with respect to time-of-day characteristics. After a formal practice session, members of the sample performed lateral (one-dimensional) tracking tasks in eight counterbalanced sessions, either with or without alcohol (0.836 g/kg), at 0900, 1300, 1800 and 0100 hours. The tasks varied in terms of smooth and ballistic motor pursuit, unpredictability and availability of target preview.


RESULTS
Alcohol markedly impaired tracking accuracy (error from target), especially in nonpreview conditions. The only evidence for an overall time-of-day effect was on a ballistic pursuit nonpreview task, but there was no indication of any alcohol by time-of-day interactions.


CONCLUSIONS
When tested 30 minutes after consumption of alcohol, sensorimotor tracking skills are markedly impaired at alcohol levels approaching the New Zealand threshold for legal driving, but these effects are not subject to circadian variations.
Dalrymple-Alford
John C
JC
Christchurch Movement Disorders and Brain Research Group, Department of Psychology, University of Canterbury, Private Bag 4800, Christchurch 8004, New Zealand. psyc338@psyc.canterbury.ac.nz
Kerr
P Anne
PA
Jones
Richard D
RD
D000328:Adult; D001334:Automobile Driving; D002940:Circadian Rhythm; D000431:Ethanol / Q000009:adverse effects* / Q000097:blood; D006801:Humans; D011596:Psychomotor Disorders / Q000139:chemically induced* / Q000175:diagnosis*; D011897:Random Allocation; D011930:Reaction Time; D012720:Severity of Illness Index; D013997:Time Factors
D000431:Ethanol