Ignition interlock devices have been getting a lot of attention lately. A number of new ignition interlock laws went into effect on the first of the year, and states like Virginia are considering strengthening their existing provisions.
The popular devices are used to punish DUI offenders, and are wired to a vehicle's ignition. Drivers can't start the car without first providing a breath sample. They are then periodically retested so as to confirm that they remain sober.
The whole process seems sort of intrusive, so you may be wondering why ignition interlock devices are legal.
For one, driving is a privilege. You have no constitutional -- state or federal -- right to operate a motor vehicle. The government can therefore restrict driving privileges so as to ensure public safety. Ignition interlock laws apply only to those who have been cited for driving under the influence and endangering the public.
This brings us to the second reason for why ignition interlock devices are legal. They're part of a scheme of criminal punishment. Individuals convicted of crimes are subject to reasonable restrictions as imposed by the court. In the grand scheme of things, a device may be more reasonable (and preferred) than a stay in jail.
If you still don't like the idea of ignition interlock devices, be aware that they aren't going away anytime soon. All 50 states currently have an ignition interlock law on the books, and 14 of them make the devices mandatory. In those states, an ignition interlock device must be installed after a driver's first DUI offense.