If you intend to get as boiled as a Tennessee rabbit on Thursday because everything is green and there are shamrocks in the bar, here are a few things to keep in mind:

Driving after drinking is dumber than trimming toenails with an electric carving knife. But chances are you know that.

A party atmosphere might make you do something you will regret the next day, such as texting an ex as if you were together or leading the gang down to the recruitment center to sign up. (Good thing you were unclear on the meaning of "Salvation Army.") Alcohol is the leading cause of coming back from Cancun with a bad tat. In other words, it lowers your inhibitions and makes you do dumb things with the risk of permanent consequences.

But now your smartphone might be able to save you from your bad judgment through apps that, supposedly, help avoid boozy foolishness. We analyzed a few of them.

Let's start with the Breathalyzer apps.

Am I Drunk is one app whose answer ought not to be a mystery, but these things are subjective. It asks such things as your weight, what you've had to drink, when you drank it and the legal limit in your area. Once this is done, you see an ad for an app that helps you "Become a Smart Investor," because anyone using an app to measure their level of spiffification is certainly in the mood to buy some Chinese Condo Futures.

Let's say you enter "White Russian," because you're at an Irish "Big Lebowski"-themed party, and one hour ago for the time. Then it asks you to blow into the microphone of your phone. Results: 0.021724. "You can drive," it says, adding, "You need a beer and a party." High-five! You can drink more!

Here's the problem: You actually believed that blowing into the microphone of a phone could determine your blood alcohol level. Forget being drunk; you are too stupid to drive. Please relinquish your keys and cut your driver's license in half.

How can a microphone determine your blood alcohol level? It can't, of course. It's like a stereo speaker telling you your body mass index.

Your phone is not some miraculous device that can MacGyver its way to analyzing the amount of hooch in your blood. It's just taking the standard amount of liquor in the drink you specified, calculating time and your weight and making a guess.

Verdict: useless.

Alconaut is an app with an icon that shows a generic human figure kneeling down and chundering, as the Aussies call it. You enter basic data: gender, weight and region. There are two choices for the last option: "Eastern Europe" and "The rest of the world." Really. Next, there are three simple choices: tap on the stein, the shot glass, the wine glass. It starts a countdown that tells you when you'll hit 0.28. Three shots will take 1:50 for Eastern Europeans; 2:45 for the rest of the world.

It doesn't seem terribly precise, but no matter what you put in, the message is "You're not sober." It suggests you take an hour and a half to deal with one beer, something that will be observed by absolutely no one. Still, the basic message — You drank? OK, then you're technically drunk — is a cautionary orange sign for anyone inclined to feel bulletproof. Not that they'll listen.

Verdict: useless.

Thumbs down

BREATHALYZER shows you a picture of something that purports to be a Breathalyzer; it looks like an old iPod, complete with a 32-pin USB cord for realism. So it's a virtual device within a device. The screen says: "Drunk? Breathe on your thumb and press the white nozzle below."

Before you roll your eyes, consider that there are people on Twitter who are legally permitted to drink who wonder why we've had 50 Super Bowls but only 44 presidents. The rest of us are well aware that there is not a single accurate measurement of anything that begins with the words "breathe on your thumb."

Nonetheless, I gave it a try. It made a beep I recognized as a computer interface sound stolen from "Star Trek: The Next Generation" and presented me with a message: "Do you have hollow legs?" I do not, so I tried it again: "Drunk as a drowned mouse."

Oh, it's a simile generator! Some other results:

• "Merry as a mosquito."

• "Hotter than a boiled owl."

• "Tip top tippler."

• "Drunk as a wheelbarrow."

• "Bent like shrimp."

• "Snoozle-wobbles."

And 20 more mostly British euphemisms. Verdict: useless.

Don't hit 'send'

As for sending texts you will regret, there are apps promising to prevent that, too.

One of them is Drunk Mode, which promotes the fact that it's free. (As if you'd pay, anyway.) It promises to watch for continual misspellings.

When you launch the app, you get instructions: "To enable the keyboard go to Settings > General > Keyboard > Keyboards > Add New Keyboard then tap Drunk Mode Free, tap Drunk Mode Free again, and turn on 'Allow Full Access' to make full use of Drunk Mode Keyboard." Basically, if you can do this, you're sober.

Once launched, the app offers the option to "Tap Here to Get Drunk Mode Feature" and asks for your Apple Store ID. Isn't this like renting a movie that tells you how to rent a movie? By this time, we've grown bored with the whole process. Delete.

Android users may enjoy Drunk Text Savior, which does the same thing as Drunk Mode.

Going back to Am I Drunk, it's rated "OK for Teens." That seems … ill-advised.

But all of these apps are ill-advised. For a day such as St. Patrick's Day, there's just one app you need: Lyft, Uber, iCab, the contact list with names of abstemious friends. Doesn't matter. Whichever one summons someone to drive you home.

James Lileks • 612-673-7858