The Bay Area GTFS Accessibility site validates the accessibility fields of all 38 Bay Area transit agencies.
It checks for:
wheelchair_accessible
field intrips.txt
wheelchair_boarding
field instops.txt
tts_stop_name
field instops.txt
levels.txt
filepathways.txt
file- Contrast ratio between
route_color
androute_text_color
inroutes.txt
These accessibility guidelines are taken from the California Transit Data Guidelines published by Caltrans.
It uses the GTFS Accessibility Validator tool.