For those interested, 1 of these prototypes, made for the US army, is surviving and can be seen at the fascinating DAF museum in Eindhoven the Netherlands (Tongelresestraat 24, 5613 DA). The interesting feature of this 500 YM (Pony prototype) vehicle is that on the rear end a steering wheel could be assembled so a person walking behind the vehicle could steer this platform vehicle.
There's even one vehicle with an official Dutch license plate registration (15-GV-41). Apparently 14 vehicles were made of which 12 were sent to the USA for testing and 2 remained in the Netherlands. One in the DAF museum and another one with the official road registration. These vehicles are equipped with a 500cc two-cylinder air-cooled boxer engine of the DAF patented Variomatic transmission.
