older big HD trucks are a gray area since most didn't have a rearview due to loads in the back rendering them useless. not opinion, fact.
Not really gray. 10,001 pounds GVWR or more...
20-117.1. Requirements for mirrors and fuel container.
(a) Rear-Vision Mirrors. - Every bus, truck, and truck tractor with a GVWR of 10,001 pounds or more shall be equipped with two rear-vision mirrors, one at each side, firmly attached to the outside of the motor vehicle, and located as to reflect to the driver a view of the highway to the rear and along both sides of the vehicle. Only one outside mirror shall be required, on the driver's side, on trucks which are so constructed that the driver also has a view to the rear by means of an interior mirror. In driveaway-towaway operations, a driven vehicle shall have at least one mirror furnishing a clear view to the rear, and if the interior mirror does not provide the clear view, an additional mirror shall be attached to the left side of the driven vehicle to provide the clear view to the rear.
§ 20-126. Mirrors.
(a) No person shall drive a motor vehicle on the streets or highways of this State unless equipped with an inside rearview mirror of a type approved by the Commissioner, which provides the driver with a clear, undistorted, and reasonably unobstructed view of the highway to the rear of such vehicle; provided, a vehicle so constructed or loaded as to make such inside rearview mirror ineffective may be operated if equipped with a mirror of a type to be approved by the Commissioner located so as to reflect to the driver a view of the highway to the rear of such vehicle. A violation of this subsection shall not constitute negligence per se in civil actions. Farm tractors, self-propelled implements of husbandry and construction equipment and all self-propelled vehicles not subject to registration under this Chapter are exempt from the provisions of this section. Provided that pickup trucks equipped with an outside rearview mirror approved by the Commissioner shall be exempt from the inside rearview mirror provision of this section. Any inside mirror installed in any motor vehicle by its manufacturer shall be deemed to comply with the provisions of this subsection.
(b) It shall be unlawful for any person to operate upon the highways of this State any vehicle manufactured, assembled or first sold on or after January 1, 1966 and registered in this State unless such vehicle is equipped with at least one outside mirror mounted on the driver's side of the vehicle. Mirrors herein required shall be of a type approved by the Commissioner.