Which item is not included in the manual’s list of bus vehicle systems that must be checked for good working order before driving?
Correct answer: D – Air-conditioning system
The Arkansas manual’s required bus-system checks include service and parking brakes, steering, lights and reflectors, tires, horn, wipers, mirrors, wheels and rims, coupling devices when present, and emergency equipment. Air conditioning is not included in that specific required list. A carrier may still inspect it under maintenance or passenger-comfort procedures.
Source: Arkansas Commercial Driver License Manual — § 4.1.1, “Vehicle Systems”

