Common Misconceptions About Ignition Interlock Devices: What’s True and What’s Not

If you have just been told you need an ignition interlock device, you have probably heard a few alarming stories already. A friend swears the device can kill your engine on the highway. A forum post claims it records everything you say. Someone else insists one swig of mouthwash will land you back in court.

Most of that is wrong. Ignition interlock misconceptions spread quickly because few people talk openly about living with a device, so rumors fill the silence. The reality is far less dramatic, and knowing what is actually true makes the next several months easier to plan for.

This article walks through nine of the most common myths and gives you the plain answer to each: what the device does, what it never does, and what actually matters for staying compliant.

Why Ignition Interlock Misconceptions Persist

Most interlock myths survive because the people repeating them have never used a device. Drivers rarely discuss their programs openly, so secondhand stories, old forum threads, and movie scenes stand in for facts.

We took on a few of these years ago in our post debunking the top three myths about ignition interlock devices, and the questions have only multiplied since. Devices have also improved considerably; advice from someone who had an interlock a decade ago may no longer apply. Here is the current picture.

Quick Reference: Myth vs. Reality

The myth	The reality
It shuts off your engine while driving	It never stops a running engine
It records your conversations	It logs breath tests, not audio
It is huge and obvious	Modern devices are compact and easily hidden
Mouthwash equals a violation	Sensors distinguish mouth alcohol; retests resolve most ambiguity
You blow constantly	One test to start, then periodic retests
A friend can blow for you	Tests are logged to you, and a camera documents the driver
It damages your car	Professional installation and removal leave the vehicle intact
It false-positives constantly	Alcohol-specific sensors plus regular calibration keep readings accurate
You can trick it	Detection technology and cameras make workarounds a losing bet

Myth 1: "It Will Shut Off My Engine While I'm Driving"

False, and this is the most important one to put to rest. An ignition interlock prevents your engine from starting; it never shuts off an engine that is already running. Cutting power to a moving vehicle would be dangerous, and the devices are simply not designed to do it.

What actually happens on the road is a rolling retest. The device periodically asks for a breath sample while you drive. If you miss or fail one, the device logs the event and alerts you; the record goes to your monitoring authority. Your engine keeps running the entire time. Our guide to the ignition interlock rolling retest explains exactly how this works.

Myth 2: "The Device Records My Conversations"

No. An interlock is not an audio recorder. It logs breath test results, along with events like engine starts and stops, and reports that data to the authority overseeing your program. There is no microphone capturing what you or your passengers say.

The confusion usually comes from the camera, which photographs the person taking the test. That is image documentation tied to test events, not surveillance of your daily life.

Myth 3: "It's Huge, and Everyone Will See It"

Modern devices are far smaller than people expect. RGI's Dräger Interlock 7000 has a sleek, discreet design and is compact and easily hidden, with a rear-mounted mouthpiece that keeps the profile low. A passenger glancing into your car is unlikely to notice anything unusual.

The clunky, dashboard-dominating box people imagine comes from older equipment and film portrayals. If discretion matters to you, and for most drivers it does, device design is worth weighing when you choose a provider.

Myth 4: "One Sip of Mouthwash Means a Violation"

Not the way people fear. Products like mouthwash, some cold medicines, and even certain foods can leave trace alcohol in your mouth. But that is mouth alcohol, not breath alcohol from your bloodstream. Mouth alcohol dissipates quickly; alcohol you have actually consumed does not.

The Dräger 7000's sensor is built to distinguish between breath alcohol and mouth alcohol, and retest procedures resolve most ambiguity: wait a few minutes, rinse with water, and test again. A sensible habit is simple. Skip alcohol-based mouthwash before driving, keep water in the car, and retest if a reading surprises you.

Myth 5: "I'll Have to Blow Into It Constantly"

You will not. The routine is one test to start the vehicle, then periodic rolling retests while you drive. Between tests, you just drive.

The test itself is quick. RGI's device uses a simple blow-suck breath test that takes about ten seconds, with no humming, no rhythm tricks, and no complicated technique to memorize. Most drivers report that testing becomes automatic within the first week or two, about as remarkable as buckling a seatbelt. It is a real adjustment, but "constantly" is not an honest description.

Myth 6: "Someone Else Can Just Blow for Me"

This one is not just false; acting on it can cost you. Every test result is logged to you as the program participant, regardless of whose breath produced it. And the camera on the interlock device documents who actually takes each test. The Dräger 7000's camera can even detect a change in driver.

Asking a friend to blow for you is typically treated as a program violation, and in many states it carries legal consequences for the friend as well. The rolling retest closes the loop: even if someone started the car for you, the device would keep asking for samples after they got out.

Myth 7: "The Device Will Damage My Car"

A professionally installed interlock does not harm your vehicle. Installation connects the device to your ignition system through wiring designed to be removed cleanly when your program ends. Trained technicians handle both ends of the process, and the Dräger 7000 installs readily in nearly any type of vehicle, including motorcycles.

Where do the horror stories come from? Mostly from do-it-yourself tampering or backyard removals, which can genuinely damage wiring and will certainly be logged as tampering events. Let the service center do the work at both ends and your car will come out of the program exactly as it went in.

Myth 8: "Interlocks Are Unreliable and False-Positive All the Time"

Device reliability is dramatically better than this myth suggests. Modern interlocks use fuel cell sensor technology that responds to alcohol specifically, rather than to the broad range of compounds that fooled older equipment. Regular calibration appointments keep that accuracy verified throughout your program.

Most "false positives" drivers describe turn out to be mouth alcohol readings from mouthwash or recent food, which a rinse and a retest resolve, or device issues that a service visit corrects. Genuine sensor errors are rare. If your device ever behaves unexpectedly, our guide to troubleshooting ignition interlock malfunctions walks through what to check before your next appointment. Reliability is, frankly, the quietest strength of a well-maintained device: it simply works, day after day, without drama.

Myth 9: "You Can Trick It if You Know the Right Hack"

Every version of this myth fails. Pennies under the tongue, mints, breath spray, holding your breath: none of it defeats an alcohol-specific sensor. We took the most famous one apart in our post on beating a breathalyzer with peanut butter, and the short answer is that you cannot.

The device measures alcohol in deep lung air. Masking the smell does nothing to the measurement, the camera documents every test, and failed workaround attempts become logged events on your record. The reliable way through an interlock program has always been the boring one: drive sober, test when asked, and keep your appointments.

Frequently Asked Questions

Will an ignition interlock device stop my car while I'm driving?

No. An interlock can only prevent an engine from starting. It cannot and will not shut off a running engine. If you fail or miss a rolling retest on the road, the device records the event and alerts you, and your monitoring authority sees the log, but your vehicle keeps operating normally the entire time.

Do ignition interlock devices record audio or conversations?

No. Interlocks log breath test results and vehicle events such as starts and stops. They do not record sound. The camera included on many modern devices, including RGI's, takes images tied to breath tests so the program can confirm who is testing.

Can mouthwash or cold medicine cause an interlock violation?

Alcohol-based products can produce a temporary mouth alcohol reading, but sensors on quality devices distinguish mouth alcohol from breath alcohol, and a short wait plus a water rinse and retest resolves most of these readings. Choose alcohol-free mouthwash and wait a few minutes after any alcohol-based product before testing.

Can someone else blow into my interlock to start my car?

They can physically blow into it, but it will not help you. Every result is logged to you as the participant, the camera documents who took the test, and rolling retests continue after the car starts. Having someone test for you is generally treated as a violation and can create legal trouble for both of you.

How often do I have to blow into an ignition interlock device?

Once to start the vehicle, then at periodic intervals while driving through rolling retests. You are not testing constantly. Each test on RGI's device takes about ten seconds using a simple blow-suck pattern with no humming required, and most drivers find the routine becomes second nature within a couple of weeks.

Will an interlock device damage my car's engine or wiring?

Not when it is professionally installed and removed. The device connects to your ignition wiring in a way that is designed to be reversed cleanly at the end of your program. Damage stories almost always trace back to tampering or amateur removal attempts, which are also logged as violations. Use a qualified service center at both ends.

How accurate are ignition interlock devices?

Modern devices are highly accurate. Fuel cell sensors respond specifically to alcohol, and regular calibration appointments verify that accuracy throughout your program. Most readings that drivers assume are false positives are actually mouth alcohol from mouthwash or food, which dissipates quickly and clears on a retest a few minutes later.

Can people tell my car has an ignition interlock device?

Usually not. Modern handsets like the Dräger Interlock 7000 are compact, easily hidden, and designed to be discreet, and there is no exterior marking on your vehicle. Unless a passenger watches you take a test, most people will never know the device is there.

The Truth Is Easier to Live With

Strip away the myths and an interlock program looks like what it actually is: a quick breath test, a predictable service schedule, and a device that stays out of your way the rest of the time. The drivers who struggle are almost always reacting to bad information, not to the device itself. If a question comes up during your program, the RoadGuard Interlock support hub covers calibration, retests, violations, and everything in between, and you can reach a real person at 1-833-545-0368. Get the facts first. The rest is just driving.

Disclaimer: This article is provided by RoadGuard Interlock for general informational purposes only and is not legal, financial, or medical advice. DUI and ignition interlock laws, penalties, fees, and program requirements differ from state to state and county to county, and they can change at any time. Any costs, timelines, or figures mentioned are general estimates rather than quotes or guarantees. Please do not rely on this article as a statement of the law where you live. Confirm current requirements with your state DMV, the court handling your case, a licensed attorney, or RoadGuard Interlock directly before making decisions. Device features, pricing, availability, same-day installation, and any promotions referenced are subject to change, vary by location, and may not be offered in every state RoadGuard Interlock serves.