(a) If necessary to protect passengers from inclement weather, including rain, snow, or sleet, the passenger compartment must be equipped with a top that is at least 80 inches above the floor and with a means of closing the sides and ends. A tarpaulin or other removable protective device may be used if secured in place.
(b) The motor vehicle must have a safe method of protecting the passengers from cold or undue exposure. A motor vehicle may not have a heater that:
(1) conducts engine exhaust gases or engine compartment air into or through a space occupied by an individual;
(2) uses a flame that is not completely enclosed;
(3) might spill or leak fuel if the vehicle is tilted or overturned;
(4) uses heated or unheated air that comes from or through the engine compartment or from direct contact with any part of the exhaust system unless the heater ducts prevent contamination of the air from the exhaust or engine compartment gases; or
(5) is not securely fastened to the motor vehicle.