Not a tracker, and not a machine that proves someone is sober all day long. It is a breath-testing device installed in a vehicle that requires the driver to blow into it before the engine will start, and sometimes again while driving. If alcohol above a set limit is detected, the car will not start or the event is recorded. The point is control and monitoring, not a free pass to drive after a DWI.

A lot of bad advice makes this sound optional or easy to work around. It is neither. In North Carolina, an ignition interlock can be required after certain impaired-driving cases as a condition of limited driving privileges or license restoration. Under North Carolina law, including G.S. 20-17.8 and related impaired-driving rules, it is commonly tied to a BAC of 0.15 or higher. The NC Division of Motor Vehicles oversees licensing consequences, and violations can lead to longer restrictions or loss of driving privileges.

For an injury claim, the device can matter in more than one way. If a crash involved a driver who was supposed to have an interlock but did not, that may support arguments about negligence, supervision failures, or prior notice of unsafe driving. On the other side, interlock records may become evidence in a personal injury case or criminal case, helping show whether alcohol use played a role before the wreck.