Tennessee has beefed-up a weapon in its arsenal of DUI prevention: the interlock system. An interlock device is a dashboard breathalyzer installation that requires a driver to blow into the device and demonstrate to the computer that he or she is below the legal limit. They cost approximately $100 per month to operate and must be installed by a professional. Although the interlock device has previously been an option for some DUI defendants, it has not been a mandatory part of a DUI or implied consent sentence until now. After January 1, a person convicted of a first offense DUI with a blood alcohol content of .15 or above (almost twice the legal limit) will be required to install an interlock device at his or her expense. Mothers Against Drunk Driving lobbied for a harsher law mandating interlock installation for offenders who registered over .08, similar to the laws in New Mexico and Arizona.
Defendants who refuse a breathalyzer test at the scene of the arrest will also be subject to a mandatory interlock installation as part of the implied consent violation, as will those convicted of DUI with a minor in the car.
The interlock system will also allow defendants whose blood alcohol level registered below .15 who get an interlock device to have much more flexibility in the conditions for a restricted driver's license - basically unlimited travel-as opposed to the former restricted license that only allowed limited travel to work, school and church.
One of the most interesting aspects of the new law involving the interlock system is what happens if a person who has an interlock device on his or her car is caught driving another car without an interlock device - that person faces an additional criminal charge that carries mandatory jail time.
The law also makes it important for you to know if your friends have an interlock device before loaning them your car. If you allow someone who is supposed to have an interlock device on their car to drive your non-interlocked car, you are committing a crime, even if neither you nor the driver has been drinking. Think twice before handing over those keys.