Which of the following must a driver confirm are in safe working condition during the bus interior safety check?

AAMVA CDL Manual Section 4.1.3, p.4-1

Each of these items is something a rider could need in an emergency, a handhold to avoid falling, a buzzer to call for help, or an exit handle to get out quickly. A driver who skips this list could send out a bus where a rider literally cannot summon help or escape if something goes wrong.