I went to a defensive driving course a few months ago as a requirement for one of my jobs. I wasn’t surprised, but the video that they played was from about 1985 (complete with yellow suits with hideous shoulder pads – yikes!) and that I had seen it several times before in other trainings. As it should be, there was a section of the course on drinking and driving.
The slide that was shown at the training had the all-too-familiar “1beer=1wine=1shot” memory trick, so that you could count on your BAC (blood-alcohol content) going up by .02 BAC with each of those, and lasting for about an hour in your metabolism. And, that after several of the same kind of drink, you could still do a rough calculation in your head about what you’d consumed in one night, and make your determination about whether or not you are able to make decisions, or drive home safely. There’s a little math, but it isn’t too bad.
So, for example, we’ll take Joe, the college drinker.
If Joe has 3 “light” beers (the typical .02 BAC increase for each x 3 = .06 BAC) when he shows up and then plays a videogame for two hours (-.04 BAC), he’s only have about one beer left in his system and would be well under the legal limit to drive home (.02 BAC). However, if Joe drinks 5 beers in an hour (.02 x 5) and then drives home immediately, his BAC of .10 would be over the limit in all 50 states and dangerous.
Those scenarios are pretty straightforward. In the end, its all about time, and quantity. This is very simple, and for years was a useful “mental check” of whether or not driving home was advisable. But, this calculation is can be dangerously wrong if you’re drinking pretty much anything other than Coors/Bud (which come in at 4.2% ABV for Bud Light and Coors Light respectively). Most of my craft beer drinking friends don’t pause to consider how wrong this rule is.
For example, the average beer from Red Hook Brewery is 5.7% ABV, Sam Adams (not including Utopias) is 6.25%, and Stone Brewing is a whopping 6.9% ABV on average .
So if we do a few more calculations, this variation could begin to cause a huge problem:
If a beer is 5% ABV, each drink will raise the BAC about .024
If a beer is 6% ABV, each drink will raise the BAC about .028
If a beer is 7% ABV, each drink will raise the BAC about .033
What does that equate to?
If Joe suddenly turns into a craft beer lover, and drinks 3 craft beers in a night, then plays a video game for two hours (same as in the previous scenario) if he’s drinking a 7% ABV (that’s .033 x 3 = .099 BAC) he’ll start off with a .099 BAC, and after two hours be down to a blood alcohol content of .059– which is not a great number.
At .05% BAC or more, “impairment occurs consistently in eye movements, glare resistance, visual perception, reaction time, certain types of steering tasks, information processing and other aspects of psychomotor performance” .
If you do the math, a small variation in ABV can have a huge effect overall on sobriety – especially as far as beer is concerned. Additionally, extreme beers, Belgian beers and others can have ABVs in excess of 9%. Which, in our scenario with Joe, would give him a BAC of .088 after 3 9% ABV drinks and two hours – he’s surpassing the legal limit for drunk driving in 50 states.
So why bring this up? This holiday season there are lots of reasons to celebrate, and lots of great holiday beers to be had. But I thought it was important to share my revelation with you that I had in the back of an otherwise unremarkable driver’s education class. The 1beer=1shot=1wine rule should be stricken from the record, because it is no longer applicable to most beer available. Please be careful this holiday season when making drinking and driving decisions, especially all of you craft beer fans out there.