1. A method for classifying a behavior of a pedestrian when crossing a roadway of a vehicle, the method comprising: reading in a sensor signal to detect the pedestrian and at least one piece of surroundings information regarding surroundings of the pedestrian, the sensor signal representing a signal of at least one sensor of the vehicle; ascertaining at least one physical variable of a relationship between the pedestrian and the at least one piece of surroundings information; and classifying the behavior of the pedestrian using the at least one physical variable.