Ignition interlock & breathalyzer devices


Ignition Interlock Devices (IIDs) are often required for individuals convicted of OWI or DUI. IIDs are constantly evolving to fully comply with government restrictions and to combat attempts to bypass the intended purpose. Here’s a breakdown of how they work. 


How do they work?

Once the car has started, additional breath tests will be required. These are referred to as random retests. At random time intervals, the driver will be alerted to provide additional breath samples. If the breath is clean (no alcohol detected) the driver can continue driving. Contrary to popular belief, if the test is failed, the engine is not turned off as that could potentially create a very dangerous situation. Instead, a log is created of the incident and the IID will trigger some sort of alarm, such as the hazard lights and car horn, to warn the driver to stop the car. These random retests are in place to prevent the driver from drinking after the car has been started. 

A record is maintained of any and all breath samples which is then provided to the authorities that had the device installed. Depending on the circumstances and model of ignition interlock, this could happen either immediately, via wireless signal, or downloaded during maintenance periods. If any violations are logged, harsher sanctions or punishments may result.


When are they used?

All 50 states have laws that permit using ignition interlocks as a substitute to sentencing for alcohol-related driving offenses. Many states require them for all first-time offenders. The remaining states have more specific laws that take into account the severity of the offense and number of occurrences by the offender.


What do they cost?

The costs of having an IID installed are usually paid by the offender. This includes the initial installation of the device (typically $75 to $150) as well as calibration costs. These calibrations typically occur at the end of 30, 60 or 90 day periods depending on the stat.


How effective are they?

  • Over 1.77 million drunk driving attempts were prevented by ignition interlocks as of March 2016.
  • States requiring all convicted drunk drivers to use an IID, such as Arizona, Oregon, New Mexico and Louisiana, have cut DUI deaths by over 30%
  • About 1/3 of impaired driving offenders are arrested for a subsequent offense. Ignition interlocks can prevent these drivers from re-offending while the devices are installed.
  • Drivers with a BrAC level of .08 or higher in fatal crashes in 2012 were seven times more likely to have a prior conviction for driving while impaired than were drivers with no alcohol.
  • Drunk driving repeat offenses are reduced by about two thirds when ignition interlocks are installed.
  • Almost all ignition interlock users reported that the device has been successful to very successful in preventing them from drinking and driving and almost all reported that the ignition interlock has been effective or somewhat effective in changing their drinking habits.


Learn more about ignition interlock & breathalyzer devices:

What is an ignition interlock device?

Ignition interlock & breathalyzer device technologies

History of IIDs & breathalyzer devices

Ignition interlock device state suspensions

IID & breathalyzer accesories

Car breathalyzers

Portable breathalyzers

Home breathalyzers

BAIID devices

Get ignition interlock pricing in your state


By clicking the button below, you consent to one or more of the listed businesses calling and texting at the telephone number provided, without regard to the time of day, to encourage the purchase or lease of DUI-related products and services, including through the use of automated technology, artificial voice and/or pre-recorded means. Consent is not a condition of purchase. For California residents, click here.