System for evaluating the traffic environment of a motor vehicle and for influencing the speed of the motor vehicle in its own traffic lane, comprising an electronic control unit, which is connected to a signal transmitter that produces a signal characteristic of the desired speed of the motor vehicle, a signal transmitter that produces a signal characteristic of the yaw of the motor vehicle about its vertical axis, a signal transmitter that produces a signal, which is characteristic of the articles situated, in the direction of travel of the motor vehicle, in front of the motor vehicle in terms of their spacing and orientation relative to the motor vehicle and which reproduces the speed relative to the speed of the system motor vehicle and/or the spacing relative to the system motor vehicle and/or the angular offset or the cross track distance relative to the vehicle longitudinal axis of the system motor vehicle, and a signal transmitter that produces a signal characteristic of the speed of at least one wheel of the motor vehicle, and which is connected to at least one control device, which influences the performance of the motor vehicle, for supplying said device with output signals derived from the performance of the motor vehicle situated in front of the system motor vehicle, whereby the electronic control unit detects a lane change of the system motor vehicle when the change of the angular offset or of the track cross distance of the target motor vehicle, upon the performance of which the performance of the system motor vehicle is to be dependent, relative to the vehicle longitudinal axis of the system motor vehicle is above a specific threshold value and substantially equal to the yaw of the system motor vehicle with an inverse sign.