Alcohol and Driving Impairment
"After drinking [alcohol], the brain works inefficiently, taking longer to receive messages from the eye; processing information becomes more difficult and instructions to the muscles are delayed. Alcohol can slow down reaction time by 10 to 30 per cent. It also reduces ability to perform two or more tasks at the same time.
"Alcohol reduces the ability to see distant objects and night vision can be reduced by 25 per cent. Blurred and double vision can also occur. Ability to perceive what is happening at the roadside is weakened. Loss of peripheral vision could be crucial. Alcohol may also create a sense of overconfidence, with the result that people are prepared to take greater risks."
"Drinking & Driving: IAS Factsheet," Institute of Alcohol Studies (London, United Kingdom: October 19, 2010), p. 3.