Half-track vehicles were developed for the US Army from the early 30s when the US Ordnance Department studied the successful Citroen-Kegresse half-tracks from France. Various firms in the USA developed half-track designs on behalf of the Ordnance Department, the Gunningham motor company producing the first, designated T1, in 1932. By 1940 development work led to the Half-track T14 in which the layout and appearance of all subsequent W.W.II period American half tracks was finalised. Later in 1940 with the war already gripping Europe, the United states commenced a big re-armament programme, and in September 1940 the existing T14 was standardised and ordered into production as the Half-track M2. The half-track was envisaged as an artillery prime mover, the M2 being equipped to tow the 105mm field howitzer and carry its crew and ammunition. This had been the original role of the French Citroen-Kegresse. The successful use of the Hanomag half-track in the armoured infantry role by the Germans in 1940 demonstrated that such a vehicle would be very useful to the US Army, so the existing T14/M2 design was adapted as an infantry carrier, with seats for infantry and stowage for their arms and equipment. Under the designation Half-track Personnel Carrier M3 this vehicle became known and more widely used than the original M2. While the M2 had internal ammunition lockers, the M3 body was 10 inches longer with a rear door. The later model M3A1, had a 'pulpit' to take an AA machine gun, while the M3 itself had a simple pedestal mount.
The US Forces made a study of the German campaigns in Europe in 1940 and appreciated that anti-aircraft defence of ground forces would be vital in any future operations where similar 'blitzkrieg' tactics involving close Luftwafte air support would probably be encountered again. In order to produce anti-aircraft vehicles quickly it was realised that the existing half-track design was big and stable enough to be adapted, though as a long term aim the Ordnance Department developed full-track AA vehicles such as the M19. Meanwhile some half-track designes were quickly produced, the T1E1 with Bendix turret, T1E2 with Maxson turret, and T1E3 with Electro-dynamic turret. These were M2 vehicles with the turret placed in the rear compartment. The turrets were of aircraft type, the T1E3 even retaining the perspex canopy. The effetiveness of the idea was proved, the Maxson turret of the T1E2 being preferred. A production prototype, the T1E4, was built, with the Maxson turret on a M3 vehicle. Standardised as Multiple Gun Motor Carriage M13, over 500 were built. An improved model, with four .50 cal machine guns was produced in April 1942, the prototype being designated GMC T58. This was standardised as Gun Motor Carriage M16, and 724 were built by White Motor Co in 1942-3. A similar vehicle (but with flat section mudguards and rounded super-structure corners) was the M17 built by International Harvester Co on the similar Half-track M5, over 1,000 of these were made.
U.S. M16 Half Track Kit - CA181