2010 ADA Standards for Accessible Design Pocket Guide

403.5.1 Clear Width.

Except as provided in 403.5.2 and 403.5.3, the clear width of walking surfaces shall be 36 inches (915 mm) minimum.

EXCEPTION: The clear width shall be permitted to be reduced to 32 inches (815 mm) minimum for a length of 24 inches (610 mm) maximum provided that reduced width segments are separated by segments that are 48 inches (1220 mm) long minimum and 36 inches (915 mm) wide minimum. [S.H. 4.2.1]

Figure 403.5.1 Clear Width of an Accessible Route