Saab alerts tired drivers

Companies as varied as Volvo, Citroen, Nissan and several truck manufacturers have come up with systems that alert the driver by shaking their seat, steering wheel or sounding audible alerts if the car or truck swerves from its lane.

However, Saab is now developing a system that prevents the driver swerving in the first place.

Their Driver Attention Warning System (DAWS) is designed to counter two of the most common causes of road accidents; driver drowsiness and inattention at the wheel.

DAWS alerts the driver by using a combination of text and voice messages, or vibrations in the seat cushion, as soon as the risk of drowsiness or inattention is detected by infra-red cameras.

Research has shown that not only are more than a quarter of accidents in Australia caused by fatigue, but death tolls from sleep-related incidents are three times higher than other accidents, presumably because the drivers do not swerve or apply their brakes.

A driver who gets behind the wheel after 17 hours without sleep is impaired to the same extent as if driving with a blood alcohol content of 0.05.

Unlike the Citroen and Volvo systems, DAWS does not rely on measuring an erratic change in the direction of the vehicle. It is designed to detect the cause, rather than the consequences.

It uses two miniature infra-red cameras, one installed at the base of the driver's A-pillar and the other in the centre of the dashboard, focused on the driver's eyes.

Software measures the driver's rate of eye blinking. When the cameras detect a pattern of long eye-lid closures, indicating drowsiness, a series of three warnings is initiated.

The first warning is a chime and a text message “Tired?” displayed on the instrument panel.

If the driver's eye-lid movement does not immediately revert to a normal wide-awake pattern, a speech message “You are tired” is delivered through the car's audio system.

If there is still no response, a stronger warning tone and the message, “You are dangerously tired, stop as soon as it is safe to do so!” will come over the audio.

This can only be cancelled when the driver presses a reset button. The system is then immediately reactivated.

The cameras are also able to monitor the driver's eye-ball and head movement.

If the driver's gaze moves away from the windscreen, a timer starts counting.

If the driver's eyes and head do not return to the straight ahead position within about two seconds, the driver's seat cushion will vibrate. This will stop once the driver's eyes and head are consistent with the vehicle's direction of travel.

However, the system software can detect when the driver is looking in the rear-view mirror, the door mirror or turning a corner, but retaining peripheral vision of the road ahead. On these occasions, it allows a slightly longer time before vibrating the seat.

However, the system will differentiate if the driver is distracted by other passengers, using a mobile phone, or changing a CD or radio station.

The system has been installed in a Saab 9-3 SportCombi for an eight-month test; supervised by the Road and Transport Research Institute in Sweden.

It is part of a development and validation process that could see the system become available in future Saab cars.