What does an ignition interlock device do?

An ignition interlock device is specifically designed to prevent a vehicle from starting if the driver's blood alcohol concentration (BAC) is above a predetermined limit, commonly set at .05%. This device requires the driver to provide a breath sample before starting the vehicle. If the device detects that the BAC exceeds the specified limit, it will disable the vehicle's ignition system, ensuring that impaired drivers cannot operate the vehicle. This technology is often utilized as a safety measure for individuals who have been convicted of driving under the influence (DUI) to help prevent them from re-offending while providing them a chance to drive legally under certain conditions.

Other options, while they relate to vehicle functionality or driver behavior, do not accurately describe the primary purpose of an ignition interlock device. It does not track speed, record driving behavior, or limit passengers, which differentiates it from other automotive technologies that serve distinct purposes.