Generous stairs and corridors
Corridors and stairs (if present) should be spacious enough so one can pass without touching or be touched by one another
Architectural spaces (stairs and corridors)
In order to
avoid unwanted or aversive bodily contact with others.
On the page Context school a variety of reasons are mentioned why students on the spectrum feel uneasy, if not outright anxious in school. The study by Wainscot et al isn’t only about bullying but about the general unease in the interaction with other students which makes those on the spectrum prefer to be alone between classes.
The mass-character of many (mainstream) schools is stressful to those on the spectrum. This stress can in part be reduced through spacious hallways and stairs. This way bodily contact is more easily avoided, something to which many on the spectrum are aversive, mostly in combination with over-sensitive touch. No doubt motor awkwardness often contributes to these difficulties; bumping into others may lead to conflict or bullying.
These considerations can be regarded as a specific instance of the general appeal for generous space standards.
Spacious corridors in which one can avoid each other even during rush hours, are of the greatest importance. Also one has to avoid dead-end corridors or other spatial possibilities for being cornered or closed in.
Stairs are critical because their number is usually more limited and alternative routes to other floors are mostly in short supply. In the design of the Leo Kanner College in Leiden (in The Netherlands; construction has started in June 2015, delivery is expected mid 2016) the architects of Mecanoo have chosen for two separate staircases, one up and one down. (See here for an impression.) Understandably this solution comes highly recommended.