The invention relates to a cruise control system for motor vehicles, comprising a sensor device for measuring operating parameters of the vehicle and for measuring the distance from a target object located in front of the vehicle, and comprising a control device for controlling the speed or acceleration of the vehicle according to the measured operating parameters and distance data. The invention is characterized in that the control device has a stop & go function for automatically control starting, rolling and stopping processes according to movements of the target object. In addition, the control device is configured for continuously testing, during the stop & go operation, for one or more predefined conditions (S3, S4) that contradict a safe stop & go operation, and in the event of such a condition, is configured for initiating a procedure (S7, S8, S9) for switching off the stop & go function.