Everyone is aware that drinking alcohol diminishes one’s ability to drive a car. However, most people are almost completely unaware just how drunk they are. It’s very common to overestimate one’s ability to drive under the influence of alcohol. That’s why so many people surrender their keys far too late.

Let’s take our typical, mythical 160-pound male. If you ask him, “Are you okay to drive?” while he’s drinking, chances are that you’ll get responses like this:

The Perception

1 Drink – Fine, no problem.

2 Drinks – It’s just 2 drinks, I’m fine.

3 Drinks – I’ll be fine if I’m careful. No problem, don’t worry, really.

4 Drinks – Yeah, you have a point, I probably shouldn’t drive.

5 Drinks –  Okay, okay, I’ll take a taxi.

This man, of course, is dreaming. A more realistic set of responses, based on his breath alcohol concentration (BAC), might be the following:

The Reality

1 Drink: (.02 BAC) – I’m probably fine, though my judgment is off a bit.

2 Drinks: (04-05 BAC) – No way. In some countries I’m already considered legally drunk. If I drive now my coordination will be messed up, and if I suddenly need to respond to something on the road, I could easily blow it.

3 Drinks: (.07-.08 BAC) – What was I thinking? My concentration is off, and my muscle coordination isn’t too good. I can’t hear or see as well as I should, and my reaction times are terrible. I won’t even be able to control my speed very well. No way I’m getting behind the wheel.

4 Drinks: (.09 – .10) – Take my keys in case I try anything stupid. I wouldn’t be able to stay in one lane long enough to make it home.

5 Drinks: .11-12 BAC. I’m hammered. Why are we having this conversation?

Sadly, one rarely hears anything like the Reality answers. But they represent a true account of what’s going on in the body of that 160-pound male. Maybe if he reads this, he’ll start relying less on Perception and accept the Reality of how alcohol affects him. If not, he might get a much harsher lesson on the roads.