Bidirectional collision-avoidance behaviour of pedestrians on stairs

Microscopic observations were performed in order to examine bidirectional collision-avoidance behaviour of pedestrians on stairs. Results suggest that characteristics of collision avoidance on stairs are different from those in a busy flat space. On stairs, pedestrians tended to detour at the beginning of a flight to avoid collision with another pedestrian already on the stairs. The authors call this lane collision avoidance. The side preference of pedestrians on stairs and the handedness of two-lane flows were explored. On dextral staircases, most pedestrians chose the right-hand side for collision avoidance, whereas in sinistral staircases, pedestrians did not necessarily choose the right-hand side. Investigation of the relative position of one pedestrian to another leading pedestrian showed that following pedestrians tended to shift laterally in relation to a leading pedestrian when the ‘front – back’ interpersonal distance between them was small. The obtained knowledge is useful for the development of pedestrian simulations.