Ignition interlock deviceSpain
An introduction to the traffic rules and road signs of Spain. Learn about driving, road safety and much more in our illustrated book, with answers to frequently asked questions.
For informational purposes only. Always follow official regulations. Some content and images were created with AI assistance.
227. 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.
Wikimedia.org • Spielvogel • CC0
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

Traffic rules
Spain