In 1938 the White Motor Company began design and testing of a new Scout Car based around a commercial truck chassis. The completed design was finalised in June 1939 and designated the White M3 Armoured Scout Car.

The "White" was designed for high speed scouting, armoured for protection and armed to fight. The White carried up to eight people including the driver.

The body of the White is created from plate steel ranging in thickness from 6mm to 12mm.

Armoured louvre shutters protect the radiator, the batteries mounted on the right side are housed in an armoured casing and a 12mm armour plate closes over the shatter proof glass windshield.

The fenders in the front are made from heavy sheet metal. The engine hood can be opened from each side. Both doors have hinged upper halves that fold down with viewing slots that have covers. The rear is a solid armour plate with no door.

A distinctive "ditchroller" mounted at the front of the bumper can be lowered to help prevent the White from bogging down in soft terrain.

On the exterior there is mountings for an axe, a shovel, a pick, jerry cans and machine gun tripods. Storage compartments are set amongst the seating in the back. Additional webbing packs may be attached to the outer plates.

A typical armament consists of a Browning 50 cal as the main gun and one or two Browning 30 cal as secondary weapons. These machine guns are mounted on a skate rail that runs around the interior of the body. All three guns can be removed and placed on tripod mounts.

The fuel tank is under driver's seat.