2010 ADAS 403.5.1 Walking Surfaces – Clear Width
Except as provided in 403.5.2 and 403.5.3, the clear width of walking surfaces shall be 36 inches minimum.
EXCEPTION: The clear width shall be permitted to be reduced to 32 inches minimum for a length of 24 inches maximum provided that reduced width segments are separated by segments that are 48 inches long minimum and 36 inches wide minimum.
Code according to 2010 ADAS. Check your state’s accessibility laws. Some states such as California, Georgia and Florida have additional requirements and standards.