Understanding Interlock Sensitivity: Real Risks Of Everyday Products

Modern alcohol interlock devices are highly sensitive tools designed to keep roads safe and help drivers prove their commitment to sober driving. But for many Australians, the reality of using an interlock day-to-day can be challenging, especially when everyday products might accidentally trigger a positive reading. 

Understanding exactly how these devices work and what items to avoid is essential for anyone required to use one whether due to a court order, workplace requirement, or personal choice.

How Interlock Devices Detect More Than Just Alcoholic Drinks

Alcohol interlocks work by analysing breath samples for the presence of alcohol before your car can start. Most devices are set to detect blood alcohol concentrations at extremely low levels, because even a small amount of alcohol can impair driving ability or indicate a breach of licence conditions. While this sensitivity is a safety feature, it leads to potential complications.

It’s not just beer, wine, or spirits that can set off an interlock. Sensitive technology means that many common household items can spark a mouth reading, including:

• Hand sanitisers and cleaning sprays that contain isopropyl or ethyl alcohol. 
• Mouthwashes, toothpastes, and breath freshening sprays with alcohol content. 
• Food items like vanilla desserts, some energy drinks, and fermented foods such as bread or pizza. 
• Certain cough syrups and cold medicines. 
• Cigarettes and tobacco. 
• Fuel or chemical (such as petrol. Diesel or chemicals). 
• Personal care products like perfumes, deodorants, or shaving lotions that linger on your hands or breath.

Each brand and model of interlock may vary, but the safest approach is to be cautious with anything aerosol, edible, or liquid that has a strong “alcohol” smell or ends with “-ol” in the ingredients.

Practical Ways To Avoid Mouth Readings

Anyone using an interlock can minimise the risk of unexpected lockouts or violation reports by following a careful routine before every breath sample.

Practical tips include:

• Wait at least 10–15 minutes after eating, drinking, or using any oral hygiene products before testing.
• Only apply hand sanitiser or lotions outside the car, keep windows open, if using these products, and allow skin to dry completely before using the device.
• Rinse your mouth thoroughly with water before taking a test. Swishing water will help remove particles that could cause a reading.
• Avoid consuming foods or drinks containing vanilla, yeast, or other fermentable sugars right before a trip.
• Be aware that certain medications (such as cough syrup) contain alcohol and ask your pharmacist for alcohol-free alternatives if possible.
• Use non-alcoholic mouthwashes and toothpastes for the duration of your interlock program.
• Keep your vehicle windows up when you are refuelling or located close to items that might have ethanol fumes such as fuel, paint and chemicals.
  

Following this routine can spare you the stress of having to explain a failed reading or having your program extended due to violations.

What Happens If You Get A Mouth Reading?

Despite the best precautions, mouth readings can happen even to the most diligent users. It’s important not to panic or give up if this occurs:

• Most interlock systems will require a retest after a short lockout, allowing any residual compounds to dissipate from your mouth and breath. 
• Use this time to rinse your mouth with water again and ventilate the car. 
• Document what you ate, drank, or used before the failed test, including brands and times, as this may help explain the result in your compliance reports. 
• If you consistently experience positives after using particular products, talk to your interlock provider they can offer troubleshooting or review your log to try to identify any possible patterns. 
• Keep records and receipts of any food, medications, or personal care items in case you need to verify your story for authorities. 

Remember: Repeated failed tests may trigger extra servicing, program extensions, or even breach penalties, so taking these steps protects both your driving privileges and your peace of mind.

Beyond The Breath Test: Interlock Challenges In Everyday Life

Living with an interlock means more than just  being careful with what you eat or use when driving. Drivers also need to manage random rolling retests, service centre appointments, and compliance reports.

Key considerations:

• Random rolling retests may happen mid-trip, requiring focus and routine to avoid issues. 
• Service intervals are mandatory; don’t miss appointments as missing them can trigger a permanent lockout until the device is recalibrated. 
• Fatigue, stress, and even residual scents in the car can contribute to problems, ventilate regularly and keep the inside of your vehicle clean. 
• Never attempt to “trick” the device, as tampering can result in program cancellation and legal consequences. 
• Retests request as you reach your destination – all retests require completion even if you have arrived at your destination. Not taking this test will result in a missed retest which could extend your program
  

If you travel with others, let them know about the device and explain why using certain sprays, snacks, or medications in the car should be avoided, too.

Stay Compliant & Drive With Confidence – Reach Out To Guardian Interlock Today!

Using an interlock doesn’t have to be stressful. By understanding how these sensitive devices work and the everyday products that might cause trouble, you can keep your program on track and your driving privileges intact. 

Guardian Interlock is among Australia’s most reputable alcohol interlock providers, with locations in every state in Australia. Therefore, you can be sure that your Guardian-approved service centre is qualified for interlock device installation, servicing, and removal of your interlock device, and our devices are compliant with your state’s regulations. Email admin@guardianinterlock.com.au or call 1300 881 005 today to get started with your alcohol interlock program. 

We understand how essential a vehicle is, whether for work purposes, family responsibilities, or other commitments. We’re committed to helping our clients remain compliant and on the road. Our customer care representatives are available to take your calls 8.30 am – 5:30 pm Monday to Friday.