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

Exterior route or destination signs on boarding side of non-rail vehicle

 2 inches 
(51 mm)

Exterior route or destination signs on front of non-rail vehicle

 4 inches 
(100 mm)

Interior signs designating wheelchair spaces or priority seats, where baseline of character is equal to or less than 70 inches (1780 mm) above the non-rail vehicle floor

 5/8 inch 
;(16 mm)

Interior signs designating wheelchair spaces, priority seats, stop announcements, or stop requests where baseline of character is more than 70 inches (1780 mm) above the non-rail vehicle floor

2 inches 
(51 mm)