The Simple Rule of Thumb That Can Get You Arrested or Killed This Holiday Season

Posted on by Jon Kelly (Jon)
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If you're like me, you enjoy having a few adult beverages during the holidays. I've found that a nice glass of beer or spot of eggnog can make the times with good friends that much better, and the times with lesser company that much more tolerable. In any case, I'm afraid that some of you might be using a simple rule of thumb to decide whether or not you should hop behind the wheel after the party ends. hide your kids, hide your wife

That simple rule of thumb?

"If I only have 1 drink per hour, I'm OK to drive."

Don't bet on it.

First, a little BACkground
Here's how it plays out. The U.S. national limit (enforced now by all states) is .08% blood alcohol content (BAC). If you get caught over that limit, you'll probably be arrested, jailed and lose your license for at least 3 months. If you hurt someone (including a passenger in your car) while over that limit, you could find yourself with a long-term prison sentence, your own real-life version of Beecher from Oz

Vern Schillinger's girlfriend, because of a few drinks

The BAC calculation charts and tools you'll find on the web are almost all based on the NHTSA formula, which I also used for my calculations in this post. The formula defines one drink as "one beer, one shot of hard liquor or one glass of wine." More about that later.

Where the rule works (more or less)
Let's say you're a dude who weighs 160 pounds (about average for a 25 year old). Using the 1 drink/hour rule of thumb, you limit yourself to four beers in four hours. According to the formula, your BAC should be between .03% to .04%. OK, you're probably just a bit buzzed. Six beers in six hours? Now you are likely somewhere around .05%, where a cop might consider you "impaired." The rule doesn't fail completely until you get to 10 & 10. Ten drinks in ten hours would likely put a 160 pound guy between .08 and .09%. In any case, you can see something clearly from these three examples -- the relationship between drinks per hour and BAC is not linear. If you're an average-sized guy, having one drink per hour, your BAC is almost certainly on the rise.

Ladies, the rule really isn't for you
File this under the "life's not fair" category, but here it is. How long does the rule of thumb work for a 120 pound woman? Not very long at all. Three drinks in three hours would likely put you over .06%, and four in four hours puts you between .08% and .09%. That's well over the legal limit. Five in five hours? Over .10%, where you could even face harsher DUI penalties in some states. 

Probably more than one drink per hour

The Santa Claus exception
On the opposite end of the spectrum, big guys can drink about as much as they want (that's why they're often so jolly, duh). The charts say that a 240 pound dude who drinks 10 drinks in 10 hours is under 0.01%. Mazel Tov!  

No worries, big guy! (photo by jason.lengstorf) 

A drink is not a drink
All of the calculations above define a "drink" as .5 ounces of alcohol by volume, or 1.25 ounces of 80 proof liquor, 12 ounces of beer, or 4 ounces of wine. The problem with this is obvious to anyone who has actually consumed a drink in real life. Unless you're in Utah, where they are required to perfectly measure every shot, you have almost no idea how much alcohol is in the drinks you're enjoying. Did you know that a Guinness Draught has just over 4% alcohol in the U.S., whereas a Coors has 5% and a RedHook IPA clocks in around 6.5%? And, don't forget that beer from a tap is usually served in a 16 oz. pint glass. 

So, if your friend has three 12 oz cans of Guinness (surprisingly good in their fancy cans), he's had about 1.5 ounces of alcohol, right on par with the beers used in the BAC charts. On the other hand, if you've downed three pints of RedHook IPA, you've had over three ounces of alcohol, the equivalent of 6 drinks as used in the formula. The story is much the same for wine drinkers. Wines vary in alcohol content from under 10% to over 15%. The assumption in the BAC chart is that you are having just four ounces of 12.5% alcohol wine per drink. A slightly bigger pour (5 oz) of 15% alcohol wine has 50% more alcohol than a standard "drink." 

The surprisingly "light" choice

The alcohol percentage is a little more consistent for hard liquor, with most common brands coming in at 80 to 100 proof (40% to 50% alcohol). The big difference comes in the pour. Depending on the type of drink and who is doing the mixing (a Utah bartender or your frat brother), each drink could have anywhere from 1 to 5 shots in it. My guess is that you're not paying that much attention to the exact ratio of Jack / Coke in your glass.   

Electronic breathalyzers
The short answer is that breathalyzers are definitely a better choice than the rule of thumb.  Many are accurate to .01% at the normal range of drunkenness where they'd be used. Amazon has a number of models that are well-reviewed, with pricing ranging from $30 to $150. Reading through the reviews, it's clear that these things are not at all foolproof (especially when you've knocked back a few). Among other things, the devices usually only work correctly after you've stopped drinking for a while and some are very specific about how you hold them and how hard you blow into them.  They also can take upwards of 30 seconds to be ready for use after being turned on, so these aren't for the impatient. Our dream device at This or That is a new edition of Angry Birds that calculates your BAC based on your ability to kill those pesky, smiling pigs. (Come on, Rovio, we know you can build it!)

If only...

What if you do have too much?
The short answer is to try to plan ahead before the party. Unfortunately, in about 95% of the U.S., cabs are not really a great option for the over-served. They're usually very hard to come by, and between the crazy stop-go driving and stench, they're usually less than awesome for the stomach after you've had a few drinks. Just one recent example: for our anniversary dinner in Breckenridge, the only cab company in town told us they could pick us up in an hour if we waited 30 minutes to call back after their shift change. Let's face it -- if you are in most American suburbs or smaller cities, getting a cab is not really a very good answer.

Yellow cab, gypsy cab, dollar cab, holla back, no thanks. (photo by dougww)

Generally speaking, the designated driver is the better option. But, nobody wants to be the dreaded DD, so here are some more creative options.  

Tip 1:  Make friends with Mormons, pregnant women and recovering alcoholics. My experience is that members of all three groups are surprising cool with their friends having a few drinks. And, there are millions of each in the U.S. (way more than there are cabs)!  

Tip 2: "Rent" a designated driver. If you're in the burbs, you're probably already hiring local teens to watch your kids. Why not hire one more to drive your friends home who've had too much to drink?

From your friends at This Or That, please enjoy yourself responsibly and stay safe this holiday season!

How do you stay out of trouble: designated driver or limited consumption?

32993 views & 314 votes

Debate It! 5

I find that staying inside and drinking like an alcoholic Scrooge has always worked for me (save that time I hallucinated that the Ghost of Drunken Christmas Mistakes visited me)

Posted By jogden,

If you're gonna plan on drinking a lot stay at your house or get a DD. It just isn't worth the risk.

Posted By joshuatitsworth,

Be safe people! Drink alone or with your buddies in the alley like Cardboard Box Bobby or Dumptruck Debbie

Posted By AnubisibunA,

but I always think I'm ok to drive...

Posted By karlakelly,

I swear to drunk occifer, i'm not god

Posted By jogden,

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