Numerous buses and coaches serve both the central bus station (Terminals 1, 2 and 3) and Terminal 4. Certain buses stop only in the central area (Terminals 1, 2 and 3) however you can transfer to Terminal 4 free on the Heathrow Express. If you have mobility problems, look for the Help Bus sign and use the telephone at stand 6 to call the bus.
 
If you need assistance to reach Terminals 1, 2 or 3 then use the telephone at the help point in the bus station located en route to the Underground.

Several local bus services are now low floor, but long distance coaches tend not to be wheelchair accessible.