The most common reason someone has to install the ignition interlock is as a result of getting a DUI. If an individual refuses the breathalyzer test or blows .15 or above, they face a lengthy suspension of their driver's license or must do the ignition interlock for one year. The only exception is if they win a MVA hearing which can be difficult since the bases to avoid the interlock is limited.

The ignition interlock carries significant expense and limitations. There are fees for installation as well as a monthly expense. Only the individual required to do the interlock can drive the car. It is possible to get a work exemption for a company vehicle.

A violation will be reported if you have a breathalyzer result of .025 or above. This means that you must abstain from alcohol or you risk alcohol remaining in your system even if you had not imbibed since the previous day. There are also failures if someone tampers with the car, the battery is disconnected, or the car is not started at least 50 times per month.

For any month where there is one or more violations, your interlock program will be extended by one month. If you have four or more months of violations,  the MVA will attempt to kick you out of the program and reinstate the original suspension in full. You can fight this at a hearing. If you are kicked out of the program, you can wait 30 days and reenter the program. However, the one years starts over again and you do not receive credit for the previous period.

You should stay away from mouth wash, certain kinds of toothpaste, hand sanitizer, paint thinner, or anything that may give a false positive. You should keep a bottle of water in your car to rinse out your mouth. If the car will not start, you can try again within 10 minutes.

Hopefully, you never need the interlock. If you do, you want to be sure to avoid any violations to get the interlock period over with as soon as possible.