Avoiding Walls: What Distance Do Pedestrians Keep from Walls and Obstacles?

To avoid colliding with walls and obstacles, pedestrians keep a certain distance to them. This so-called separation distance or wall clearance distance was documented in early literature on pedestrian transport. For modelling purposes, it can be subtracted from a walkway’s width to obtain an effective width. Literature on this topic is scarce and the values that can be found are often contradictory, largely due to a lack of data. This work aims at contributing to the knowledge about the pedestrian wall distance by applying several high-resolution measurement techniques. Measurements were carried out using ultrasonic transducers and laser scanners at locations where high numbers of pedestrians move in a unidirectional flow. The results confirm that pedestrians keep a minimum distance to walls and that the effect of obstacles is noticeable several metres downstream of the cross section in which they occur. Furthermore, it was found that the kept distance depends on the pedestrian density. Lastly, this paper suggests a method for determining the effective width of walkways that can be used in pedestrian facility design.