A separation controller for motor vehicles, having a localization device for measuring separations from preceding vehicles, an actuator system for intervention in the longitudinal guidance of the own vehicle, and an electronic control device for applying control to the actuator system and for regulating to a target separation the separation from a preceding vehicle in the own lane, wherein the control device has an adjacent-lane mode in which the target separation is modified as a function of a measured separation from a vehicle driving in an adjacent lane.