If you have an ignition interlock in your vehicle, your relationship to alcohol has probably changed. You know enough not to drink if you are going to drive in the near future.

Interlocks are sensitive devices – they have to be, since they’re designed to detect alcohol at a concentration of about .02 BAC, which means that there is .02 grams of alcohol in every 100 milliliters of your blood.

If there’s that little amount of alcohol in your blood, then there is even less in the breath that’s escaping from your lungs, yet the device needs to register that amount, which is okay. But problems sometimes happen if there’s alcohol from another source wafting into the interlock mouthpiece. Believe it or not, that small amount can fool the interlock into believing that you’ve been drinking.

What can trigger the ignition interlock?

• Windshield washer fluid. If it’s cold and you defrost your window, the alcohol could cause a fail. One trick is to use vinegar and water – or use a scraper.
• Perfume and cologne. Alcohol is a common base for these, and they can make you look bad in front of your ignition interlock. Don’t use them. That goes for aftershave too.
• Hair spray and hair gel. Anything that dries fast does so by using alcohol as a solvent. Alcohol in one form or another is also good for getting sticky substance solvent and airborne. It’s best not to use hair spray or gel before driving.
• Hand sanitizers.  These products are almost all alcohol-based, so if you use them before taking an interlock test, you’re almost sure to have it register in the mouthpiece.

It’s doubtful that any of these products would trigger a permanent lockout – the amounts are small. But they could cause a temporary fail, which would be an inconvenience. So why take the chance? Be careful about the personal products you use, and you’ll have no problem. Just follow your nose.