A motor vehicle must be equipped with mirrors as outlined under 49 C.F.R. 571 and RCW 46.37.400. The mirror mountings must provide for mirror adjustment by tilting both horizontally and vertically. The following definitions must be used for additional backup alert devices or mirrors required under RCW 46.37.400(3):

(1) Backup alert devices means any type of motion detection device, laser device, camera, or television device mounted on a truck with a cube-style, walk-in cargo box up to eighteen feet long, which will warn the driver of the detection of a person or object at a minimum of six feet to the rear of the vehicle and also encompass the width of the rear of the vehicle.

(2) Rear crossview mirrors means any type of mirrors which, when mounted, will allow the driver of a truck with a cube-style, walk-in cargo box up to eighteen feet long, to view a minimum distance of six feet to the rear and encompass the width of the rear of the vehicle in order to be able to detect an object or person. These crossview mirrors must be installed in a manner that will satisfy the above requirements.