Driver Alert Control: How does it work?

Driver Alert Control
Publié le Traduit avec l'aide de l'IA à partir de notre article original (source :

Driver alert control, abbreviated as DAC, is a driver alertness control system developed by the Volvo car company.

Unlike the systems of other car companies, the Driver alert control developed by Volvo does not control the driver's behavior but the movement of the car.

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Driver Alert Control Function

The DAC turns on when the speed exceeds 65 km/h (40 mph) and starts monitoring the movement of the car on the road. Driver alert control distinguishes controlled driving from uncontrolled driving and can estimate the driver's vigilance based on the driving method and style.

This system can also recognize situations when the driver is not fully dedicated to driving and is distracted by, for example, a mobile phone or other influences.

DAC Components

The DAC consists of a camera behind the interior rearview mirror and various other sensors and a control unit. The camera monitors the space in front of the car, the direction of travel, and also the distance of the car from the horizontal road markings.

The sensors and sensors of the DAC detect the movements of the car in all directions. The control unit records all the above data and compares it with the stored values.

How does the DAC warn the driver of fatigue?

If, based on the measured data, the control unit of the DAC recognizes that the driver is tired, it will play an audible signal. On top of that, the coffee cup warning light (white light) will light up on the dashboard.

This warning light tells the driver to stop the vehicle and rest. In addition to the mentioned warning light, the DAC can also inform about the driver's degree of fatigue, which is evaluated on a scale from 1 to 5.

However, the driver alert control does not interfere with the control of the car but only warns of the driver's fatigue and weakening of his attention. Therefore, all responsibility for driving still remains with the driver himself.

Advantages of the DAC

Although the system does not interfere with the control of the car, it evaluates fatigue and warns the driver, thanks to which it helps to avoid accidents. The point is that the fatigue warning can prompt the driver to take a break.

So it can be said that the driver alert control helps the driver maintain attention, especially during long and boring drives on the highway.

Disadvantages of the DAC

Despite its simple function to warn the driver of fatigue, the driver alert control also has a disadvantage: the driver's overreliance on this system. However, this drawback could be applied to any electronic system.

Another disadvantage can be, under certain circumstances, incorrect evaluation of fatigue, which can be annoying.


The concept of the DAC is straightforward, and it is a smart gadget, especially for less attentive drivers or drivers who undergo long boring drives on the highway or at night.

A short video demonstration of how the DAC system works: