From 1935, the co-founder of DAF Hub van Doorne and captain engineer Piet van der Trappen had started a number of armoured fighting vehicle paper projects based on their "Trado" suspension system. The Trado, named after themselves (Trappen — Doorne), consisted of a leaf-springed bogie with two actuated road wheels that could be easily attached to, driven by and rotate on the back axis of any commercial truck, thus adding a "walking beam" to the vehicle that significantly improved its cross-country performance. The Trado III suspension system, an improved version, was a considerable commercial success and applied to many existing and new civilian and military truck types. The armoured vehicle projects had the designation "Pantrado" in common, a contraction of the Dutch word for "armoured car", "Pantserwagen", and "Trado".