If you have received a DUI, you know first-hand the myriad of consequences that accompany this violation. In addition to paying hefty fines, state law may require you to have an ignition interlock device installed in your vehicle. Designed to measure your blood alcohol content level, these devices control your ability to operate your car. 

Ignition interlock devices allow you to continue driving during a license probationary period. The device, however, will continue to monitor your alcohol consumption when it comes to getting behind the wheel. 

How do ignition interlock devices work? 

Interlock devices install directly into the ignition system of the vehicle, with a monitor that sits on the dashboard. Before the car will start, you must blow into a tube connected to the device. The machine then measures your blood alcohol content level to see if you are at or below a preset level, which is usually 0.02. If the BAC is within range, the car will start and allow you to drive. The system also accounts for the following: 

  • Attempts to start the vehicle 
  • BAC levels 
  • Failed attempts and lockouts 
  • Machine calibration 

Rolling retests prompt you to provide a breath sample periodically during the drive to keep the vehicle running. 

If your BAC is above the preset limit, the car will not start and you must wait before you can try to start the car again. The system records all information, including BAC levels, startup attempts and lockouts within the device and transfers it to law enforcement during regular IID maintenance. 

Are all offenders required to get an IID? 

Some states require all DUI offenders to have an IID installed in their vehicles. Yet, in Colorado, first time DUI offenders have the option to have an IID after a nine-month driver’s license suspension. Offenders must use an IID for at least one year if they have a BAC of 0.17 or higher.