Respective movements and positions of traffic participants arranged within a monitoring range surrounding a motor vehicle are captured on the front side, on the rear side, and/or laterally, by several sensors of the motor vehicle. One characteristic value per traffic participant is established which quantifies a collision probability of the motor vehicle with the respective traffic participants in dependency on the captured movements and positions of the traffic participants and the movement and position of the motor vehicle. At least one warning message is issued with respect to the traffic participants, for which the established characteristic values reach a predetermined collision probability value, wherein the warning message is signaled in which direction of the motor vehicle the respective collisions are impending.