36 CFR Part 1192 Americans with Disabilities Act (ADA) Accessibility Guidelines for Transportation Vehicles (2016 Non-Rail Vehicle Guidelines)

T302.3 Openings.

Openings in walking surfaces shall not allow the passage of a sphere more than 5/8 inch (16 mm) in diameter. Elongated openings shall be placed so that the long dimension is perpendicular to the dominant direction of travel.

EXCEPTIONS: 1. Wheelchair securement system components affixed to walking surfaces shall be permitted to have openings 7/8 inch (22 mm) maximum in width provided that, where such openings are more than 5/8 inch (16 mm) in width, they contrast visually with the rest of the walking surface either light-on-dark or dark-on-light.

2. Ramp and bridgeplate surfaces shall be permitted to have one opening 1½ inches (38 mm) maximum in width and 4½ inches (115 mm) maximum in length to allow the operator to grasp the ramp or bridgeplate for manual operation.