Lane Keeping Assist: Always on the Right Track
Long drives will eventually cause lapses in any driver’s attention. If you are tired or simply inattentive, you can quickly find yourself “off track”. One in six serious road accidents in Germany is caused by a vehicle leaving its lane.
The Lane Keeping Assist feature for passenger cars addresses the situation by warning the driver or even taking corrective measures automatically via ESP® as soon the system detects that the vehicle has left its lane.
A camera in the windscreen films the lane in front of the vehicle and passes the data to an electronic control unit that detects the lane and markings using differences in contrast. At the same time, it determines the position of the vehicle itself. If the control unit detects that the vehicle has left the lane unintentionally, a vibration motor in the steering wheel warns the driver.
The warning is subtle but clear and can help to prevent accidents in an efficient manner. There is no warning if the driver accelerates before overtaking or joining a motorway, brakes heavily or enters a bend, for example. If the vehicle is about to drive over a solid line and the driver does not react, the system intervenes and attempts to move back into the lane using targeted, one-sided braking. As soon as the system detects a manual driving manoeuvre, it ends the automatic intervention.
In trucks, the Lane Keeping Assist feature works using audible, directional warning signals which make the driver aware that the vehicle’s course needs to be corrected. The audible warning signal stops if the driver indicates, but the Lane Keeping Assist function remains active, which is used at speeds greater than 60 km/h or, in other words, on longer distance routes.
The Lane Assistant for buses shows just how intelligent and sophisticated Daimler’s safety systems are. Here, too, a camera in the windscreen monitors the vehicle to make sure it maintains the correct course in its lane. The main point of concern for the bus developers was coming up with a suitable form of warning for the driver. An audible warning of the kind used in trucks was out of the question as this would inevitably unsettle the passengers. The solution: two vibration motors integrated in the driver’s seat cushion, which make the driver aware of the situation when the vehicle crosses the detected lane markings unintentionally and also indicate on which side of the lane this has occurred. Similar to the version for trucks, the system, which can be switched off, is activated at speeds greater than 70 km/h or, in other words, on longer distance routes. As soon as the driver indicates, the warning signal is suppressed while a visual indicator in the display instrument remains active.