What is an ignition interlock device?

Ignition interlock devices are breathalyzer systems installed in vehicles to prevent drivers from starting the engine if they have been drinking alcohol. The driver must blow into the device, which measures blood alcohol concentration (BAC), before the car will start. If the BAC is above a preset limit, the vehicle will not start. These devices are commonly required for individuals convicted of DUI or DWI offenses to promote safer driving. They also help reduce repeat offenses by monitoring driver sobriety.