American Public Transportation Association - APTA's directory of large U.S bus systems (200 buses or more). See also: International Transportation Links.
ADA Paratransit Services in America - Database of paratransit maintained by Easter Seals Project ACTION
Directgov - Travel planner on U.K Government website.
National Paratransit Directory - 1-800-TAXICAB's directory of accessible services in United States.
National Transit Database - Federal Transit Administration's (FTA's) primary national database for statistics on the transit industry.