CA Veh Code Section 28081

The provisions of Section 28080 shall not apply to either of the following:

(a)

Any motor vehicle upon which a camper is mounted if a person is able to move between the cab portion of the motor vehicle and the camper.

(b)

Any motor vehicle upon which a camper is mounted, which motor vehicle is equipped with a sliding or removable rear window which can be opened or removed by a person inside such camper.