A longitudinal driver assistance system in a motor vehicle includes a detection system for recognizing upcoming relevant events which require a change in the maximum permitted top speed, and a functional unit which, upon recognizing a relevant event, determines a location-dependent time taking into consideration the location of the relevant event. Upon achieving this, the functional unit prompts the transmission of request information for permitting an automatic adaptation of the current maximum permitted top speed to a new maximum permitted top speed. With the determining of the location-dependent time, the functional unit is also configured to take into consideration a predetermined minimum duration for the transmission of the request information.