How Interlocks Work

Drivers convicted of an Arizona DUI are required for a period of time to only operate a vehicle with an ignition interlock device (IID) installed. An IID is a breathalyzer with computer logic and memory that interconnects with the ignition and other vehicle control systems. The interlock measures the blood alcohol concentration (BAC) of the intended driver, and prevents the motor vehicle from being started if the BAC exceeds the limit of .03%.
Research has shown that the human body produces its own supply of alcohol on a continuous basis, 24 hours a day, seven days a week; it’s called endogenous ethanol production. A person can naturally produce a BAC of anywhere between .01% and .029% which is why the interlock device is programmed to detect a BAC of .03% and over.
The interlock will ask for random breath tests while the vehicle is running. If you acquire two start-up test violations, one rolling-retest failure, or the device detects tampering, you must immediately have the interlock device serviced, or it will lock-out the car from further operation. Any violation can cause an extension of your interlock term and affect the status of your driving license.
FAQs
Q: How soon can I get the interlock installed?
A: Right away, but first what is the status of your license? Are you eligible for installation? If so, we generally have same day appointments available at all 6 installation and service centers.
Q: Will my interlock fail me for eating pizza or salad or drinking diet soda?
A: No it will not. Our interlock device uses fuel cell technology that helps eliminate false positives.
Q: Is it true interlocks can’t be installed on a Prius or other push-button ignition vehicles?
A: No it is not true; our technicians can install interlocks on both a Prius and all other push button vehicles. There is no extra charge for installation on these vehicles.
Q: What happens if I move to a different state?
A: There are several Guardian Interlock providers throughout the country, we would simply transfer your contract to your closest provider.
Q: Does my car turn off while I’m driving?
A: Absolutely not. Our interlock is incapable of shutting off the vehicle.
Don’t Have Your Interlock Term Extended
- Take EVERY rolling retest.
- Ensure the device is completely powered off prior to disconnecting the handset.
- Do NOT blow into the device after consuming alcohol.
- Make ALL of your scheduled compliance appointments.
- Contact your Driver Advisors prior to performing any maintenance on your vehicle.
- Talk to our Advisors about the benefits of purchasing an AlcoHawk Pro portable breathalyzer.






