Method for monitoring lanes and lane monitoring system for a vehicle

The method involves detecting (St1) a traffic lane of a vehicle by a camera of the vehicle. The driving condition measuring signals of the vehicle are recorded (St2). The driving condition of the vehicle is judged (St3,St4) according to a traffic lane leaving-criterion. A traffic lane leaving-warning signal is generated (St7) depending on the evaluation according to the traffic lane leaving-criterion. The fulfillment of the decision criteria for the detection of a proposed trajectory shortening process is checked (St5,St6) during the fulfillment of the traffic lane leaving- criterion. An independent claim is included for a control unit for a traffic lane monitoring system of a vehicle.