Lane Departure Warning

Lane Departure Warning systems detect markings in the road and warn a driver if he or she unintentionally leaves their lane without using the turn signal. Most systems use a forward facing camera mounted inside the windscreen by the rear view mirror. When the system finds that the vehicle is leaving its lane without a turn signal, it warns the driver with a warning light on the dashboard or a warning sound. Some systems vibrate the steering wheel or the driver’s seat on the side the car is drifting.

ISO symbol for lane departure warning
As a car drifts off to the shoulder of the road, the driver is notified by an alert sound and graphic displayed on the dash.


  • These systems may only operate over limited speed ranges. Most operate at speeds over 60 km/hr.
  • Warnings stop if the driver turns on the turn signal.

Things to keep in mind

  • The warning system reacts when a vehicle appears to be drifting out of its lane.
  • This is a warning system only.
  • A lane departure warning systems does not take control of your vehicle or prevent you from driving.
  • These systems do not work without clear lane markings, on curvy roads, or in inclement weather
  • Drivers are encouraged to read the owner’s manual to become familiar with the system and the conditions when system operation is different or is not guaranteed.
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