Published by Gerald Ferreira Date: April 30, 2012

Preventing microsleep

Now also features in the Volkswagen Passat Alltrack

  • Fatigue is one of the main causes of serious accidents
  • Characteristic steering movements indicate fatigue
  • Driver drowsiness detection now a standard feature in Volkswagen’s Passat Alltrack

Bosch Driver Drowsiness Detection

Fatigue and microsleep at the wheel are often the cause of serious accidents. However, the initial signs of fatigue can be detected before a critical situation arises. Bosch Driver Drowsiness Detection can do this by monitoring steering movements and advising drivers to take a break in time.

The required information is provided either by the car’s electric power steering system, or by the steering angle sensor, which is part of the car's ESP® anti-skid system. The feature can therefore be installed cost-effectively and helps further increase road safety. Bosch Driver Drowsiness Detection can be used in passenger cars and light commercial vehicles, and can also be integrated into various control units in vehicles. It was first introduced as a standard feature in 2010, in the new Volkswagen Passat. The latest model with the function is the new Passat Alltrack.

The influence of fatigue on accidents has been demonstrated in a number of studies. In 2010, the American Automobile Association (AAA) published an analysis based on the accident data collected by the National Highway Traffic Safety Administration (NHTSA) in the United States. The assess­ment showed that overtired drivers were at the wheel in 17 percent of all fatal accidents in the US.

Fading concentration and fatigue compromise the driver’s steering behavior and response time. Fine motor skills deteriorate, and steering behavior becomes less precise. The driver corrects small steering mistakes more often. The new driver drowsiness detection function is based on an algorithm which begins recording the driver’s steering behavior the moment the trip begins. It then recognizes changes over the course of long trips, and thus also the driver's level of fatigue. Typical signs of waning concentration are phases during which the driver is barely steering, combined with slight, yet quick and abrupt steering movements to keep the car on track.

Based on the frequency of these movements and other parameters, among them the length of a trip, use of turn signals, and the time of day, the function calculates the driver's level of fatigue. If that level exceeds a certain value, an icon such as a coffee cup flashes on the instrument panel to warn drivers that they need a rest. The Bosch Driver Drowsiness Detection function addresses an important aspect of the driver's condition, and can thus contribute to improving road safety.