Road departures can be fatal, especially since the majority of them happen on motorways and rural roads. According to the U.S. Department of Transportation Federal Highway Administration, approximately 55% of traffic fatalities in the U.S. involve a vehicle crossing the roadway or centre line. In Germany, 60% of fatal road accidents and 25% of non-fatal road accidents occur on rural roads, according to the German Federal Statistical Office DESTATIS.

The Continental Road Departure Protection systems will automatically steer a vehicle back into its lane when it begins to inadvertently leave the road or cross the centre line into dangerous oncoming traffic. The systems differ from Lane Keeping and Lane Departure Warning systems in that they specifically monitor the outside boundaries of the roadway and act with more authority to keep the vehicle within its intended space.

The base system, which uses a forward looking mono camera to detect roadway boundaries, monitors the driver’s steering angle and vehicle path through existing Electronic Stability Control (ESC) sensors and also uses chassis motion sensors to identify if the vehicle is crossing the road boundary. It then uses the existing ESC system to apply the individual wheel brakes to automatically steer the vehicle back on the road while simultaneously warning the driver and reducing the speed of the vehicle for safety reasons.

This active intervention is signalled when the vehicle senses it is departing the road. The system’s performance is enhanced by road edge rumble strips, creating an opportunity for a combined vehicle plus infrastructure solution with high effectiveness. The system is designed with a driver intention recognition feature in the event that the driver does intend to leave the roadway for any reason.

Besides realizing a Road Departure Protection system with a mono camera and ESC, Continental is working in parallel on an Enhanced System: A system that uses a stereo camera and long-range radar for improved detection of roadway boundaries, particularly for country roads in Europe. The long-range radar and the stereo camera of the Enhanced System allow the generation of an occupancy map that contains information about the occupancy state of a tessellated area in the vehicle’s field of view. Based on this map, a further confirmation of road departure and potential collisions with solid borders like kerbstones, guard rails or construction site equipment is provided. The goal is to detect road boundaries, even when lane markings are missing. A coordinated brake and steering intervention will increase the efficiency of this system.

The further integration of road map data and on-board GPS can also support an advanced preview ESC feature that detects the course of the road before entering a curve. Based on the predicted upcoming road curvature, the driver is supported in situations where the driving dynamics are critical, for example with inappropriate speed during curve driving on a country road or tight curves, to keep the vehicle within the possible physical limits of the road.