A device for longitudinally guiding a motor vehicle includes a sensor system for locating preceding vehicles, a regulator that regulates the speed of the vehicle to a setpoint speed, either in a free driving mode or in a following driving mode, the setpoint speed depending on the distance from a preceding vehicle, as well as an interface to a navigation system that provides information concerning the route traveled, and a limiting device for limiting the setpoint speed based on the information provided. The limiting device is designed to deactivate automatically when changing from free driving mode to following driving mode and activate automatically when changing from following driving mode to free driving mode.