Evaluating accessibility guidelines

Case One: T-shape Space (http://www.access-board.gov/adaag/html/figures/fig3b.html)

ADAAG description: The T-shape space is 36 inches (915 mm) wide at the top and stem within a 60 inch by 60 inch (1525 mm by 1525 mm) square.

Assessment: The outcome of motion planner matches corresponding ADAAG code.

·   Wheelchair turning radius: 24 inches.

Case Two: 90 Degree Turn (http://www.access-board.gov/adaag/html/figures/fig7a.html)

ADAAG description: A 90 degree turn can be made from a 36 inch (915 mm) wide passage into another 36 inch (915 mm) passage if the depth of each leg is a minimum of 48 inches (1220 mm) on the inside dimensions of the turn.

Assessment:

The outcome of motion planner matches corresponding ADAAG code.

·   Wheelchair turning radius: 24 inches.

Case Three: Space Needed for Smooth U-turn in a Wheelchair (http://www.access-board.gov/adaag/html/figures/fig3a.html)

ADAAG description: The space needed for a smooth U-turn in a wheelchair is 78 inches (1965 mm) minimum by 60 inches (1525 mm) minimum.

Assessment:

A smooth U-turn is possible only if a wheelchair has a turning radius of less than six inches; in order to make the turn, one wheel of the chair must roll backward while the other rolls forward. Therefore, the motion depicted by ADAAG in Figure 3  (i.e., the picture on the left) is rather misleading.