ABA Accessibility Standard for GSA Facilities Pocket Guide

802.1.3 Depth.

Where a wheelchair space can be entered from the front or rear, the wheelchair space shall be 48 inches (1220 mm) deep minimum. Where a wheelchair space can be entered only from the side, the wheelchair space shall be 60 inches (1525 mm) deep minimum.

Figure 802.1.3 Depth of Wheelchair Spaces in Assembly Areas