A lane detection system detects whether the driver is unintentionally leaving the lane and warns him or her in the event of an unintended lane change. Such systems use detectors to scan the road surface while driving. If the vehicle leaves the lane above a certain speed without using the turn signal, the lane departure warning ( LDW) system triggers an alarm. This can be haptic and can be felt, for example, in the vibration of the driver's seat. Depending on whether the car has left the lane on the left or right, the driver's seat vibrates on the left or right side. The driver can then correct his direction.