What Is An Ignition Interlock Device?

An ignition interlock system is an "add-on" or "aftermarket" device that is installed in your vehicle. Once installed, the device must return a "successful" reading before the car can start. If you fail the breath test, the vehicle will not start, and most units give you a waiting period before you can test again. Ignition interlocks are optional devices, but many states offer programs where part of a DUI punishment may be reduced or set aside if the offender agrees to install an ignition interlock system in all vehicles they own. The California DMV and ignition interlocks go hand in hand for some offenders, who choose the interlock system as a way to hang on to driving privileges in a state where driving is a virtual necessity.