Driving drowsy is like driving drunk

By Karyn O'Keeffe 10/08/2012


This one is an oldie but a goodie, and still as relevant as ever…

Just over 10 years ago, Australian researchers showed that our performance at the end of the day, on a day where we’ve decided to stay up late, was similar to our performance when driving drunk. 

Essentially they compared how we function when given a placebo drink, at different levels of alcohol intoxication, and when we are asked to stay awake for long periods of time.  Not surprisingly, our performance on a range of simple and complex tasks gets worse as our blood alcohol levels (BAC) increase.  However, our performance also gets worse the longer we stay awake.  These individuals woke up at the beginning of their normal day, stayed awake all day and then were asked to stay up through the following night.  All up, they were awake for 28 hours.

It seems our performance stays fairly stable up to 17 hours after we wake (on a usual working day, about 11pm) but after then it steadily declines.  Our ability to do complex tasks, such as driving, decreases much more rapidly than our ability to do something simple like respond to a single visual cue.

They found that our performance after we have been awake for sometime in the range of 17-19 hours is similar to that when we have a BAC of 0.05% (the legal driving limit in many countries).  They also found that our ability to function after we have been awake for about 20 hours (about 2am) (on complex tasks like driving) and about 25 hours (on the simplest tasks), was similar to our performance at a BAC of 0.10% (over the limit in New Zealand).

Something to think about…