The Citroen Tractions were first introduced in 1934 and represented a major leap in car technology.
The Citroen Traction 7 model introduced first (the Light 12 in England), followed by the 11bl (Legere, Light 15 in England) and 11b (Normale, Big 15 in England). The 15-6 introduced in France in 1938 and followed in 1940 by the Big 6 in England. Long wheel base models of the Citroen Traction 11cv and six were made available, known as the Familiale in eight seater guise but with a normale boot and as a commerciale with a top hinged, modern style tailgate.
Roadster version of the 11bl and b models were available pre-war, as were the Faux Cabriolet. The Slough built Light 15 was also available as a roadster pre-war. Very few pre-war 15-6's roadsters were built but no Big 6 Roadsters were made in the UK.
In the 1930's Citroen Tractions set new standards for comfort, handling and performance but by the end (1957) the Traction lacked the modern 4 speed gearbox and the styling of the later Fords and Vauxhalls plus a very poor boot. Citroen Tractions continued to be used all over the world especially in places like Vietnam where they were used as taxis well into the 70's. My own 15-6 originates there.