Ignition Interlock Calculations: What Is An Ignition Interlock System

An ignition interlock device attaches a breath-alcohol analyzer to a vehicle's ignition system. All DUI offenders (except first-time offenders with a BAC below .15) are required to have an ignition interlock device on the cars they drive-even those who receive a deferred prosecution. When the ignition interlock device is installed on a vehicle, the driver is required to blow into the device, which reads the person's BAC level. If alcohol is detected, then the engine will not start. After starting the car, the driver is required to take the breath test every ten minutes while operating the vehicle. The device also keeps a record of every breath test result and generates a report that is sent to the courts.

The amount of time a DUI offender is required to have ignition interlock on his or her car varies according to previous offenses and restrictions. The first-time offender with a BAC above .15 will be required to have ignition interlock for one year. A second-time offender, who was previously restricted for one-year will be required to have ignition interlock for five years. A third-time offender who was previously restricted for five years will be required to have ignition interlock for no less than ten years.

The offender will be required to pay the cost of the ignition interlock rental, which is about $2 a day. A court may waive the requirement for ignition interlock if the device is not reasonably available in the local area.