Ignition interlock deviceSweden
208. Ignition interlock device
An ignition interlock device, also called an alcohol interlock or alcolock, is a breath-testing device connected to a vehicle’s ignition system. Before the vehicle can be started, the driver must provide a breath sample below a programmed alcohol limit. The device may also require additional tests during a journey and can record information about tests, failed attempts and possible tampering. Ignition interlocks are used in some countries as a safety measure or legal requirement for drivers convicted of alcohol-related offences.
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What is an ignition interlock device?
An ignition interlock device is a breath-testing system connected to a vehicle that prevents the engine from starting when the driver’s alcohol concentration exceeds the programmed limit.
🔗 nhtsa.gov • US NHTSA, alcohol ignition interlocks and post-start retests
How does an ignition interlock work?
Before starting the vehicle, the driver provides a breath sample. If the alcohol concentration is below the permitted threshold, the vehicle can be started.
🔗 nhtsa.gov • US NHTSA, alcohol ignition interlocks and post-start retests
Can an ignition interlock require another test while driving?
Some interlock programmes require repeat breath samples during a journey. Follow the device and programme instructions, and do not attempt a test in a way that compromises vehicle control. The timing and response to a failed or missed test depend on the system and local rules.
🔗 nhtsa.gov • US NHTSA, alcohol ignition interlocks and post-start retests

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