1. A method for operating a driver assistance system for a vehicle, comprising: determining a current position of a pedestrian in an environment surrounding the vehicle; determinaing a first current state of motion of the pedestrian; determining a second current state of motion of the vehicle; calculating a sojourn probability distribution of the pedestrian, the sojourn probability distribution being a function of time and of space and being based on a pedestrian motion model in connection with the determined current position of the pedestrian and the determined current state of motion of the pedestrian; calculating a trajectory based on the calculated sojourn probability distribution of the pedestrian and on the second current state of motion of the vehicle, with a minimum collision probability for the vehicle; and operating the driver assistance system of the vehicle based on the calculated trajectory.