The device uses advanced technology and sophisticated algorithms and comprises a small forward-facing camera connected to an on-board computer. The camera is mounted on the back of the rear-view mirror and is trained to identify lane markings on both sides of the vehicle.

When the vehicle is on the move, the computer looks at the road ahead and predicts where the car should be positioned relative to the lane markings. It then measures where the vehicle actually is and if the difference is significant, the system issues a warning.

First a soft warning will pop up in the instrument cluster as a text message and will stay there for 10 seconds with an accompanying chime. If the driver continues to demonstrate drowsy behaviour, a hard warning will appear in the instrument cluster which the driver must acknowledge by pressing an OK button. If the driver doesn't do so, the system can only be reset by stopping the car and opening the driver’s door.

Although Driver Alert’s camera is trained to look for lane markings on both sides of the road it will function if markings on just one side are detected. The system can be switched off via the instrument cluster.

Driver Alert is available as part of the optional Driver Assistance pack offered on Ford Mondeo, S-MAX and Galaxy models and was most recently introduced on the new Ford Focus.