This advertisement from Volkswagen is promoting its driver fatigue detection system that is now available in some models.
The driver fatigue detection system itself is pretty self explanatory. Tired drivers are dangerous drivers because their focus decreases and their reflexes slow down. A lot of accidents occur because of driver fatigue, whether that means they drift into a ditch or run into slowing traffic so this system is designed to alert drivers when they are too tired and should stop driving.
This advertisement does a perfect job of communicating the essence of this system by playing on the well known sleep tactic of counting sheep. The idea is as you fall asleep while driving the sheep start sailing by. The wall shown in the ad represents the driver fatigue detection system, which stops the sheep in their tracks.