In the 1930s the number of motor vehicles was growing rapidly all over the world, and more than 80% of them were used for private transport - individual mobility was on the way up at last. It was in this environment that Auto Union AG was created. On 29th June 1932 Audi, Horch and DKW joined forces to create the Auto Union. A purchase and leasing agreement was concluded at the same time with the Wanderer company, for the takeover of its automobile division. At the stroke of a pen, Germany's second largest motor vehicle manufacturing group had been created. The new emblem, with its four intersecting rings, symbolised the inseperable character of the new undertaking according to the will of the four founder companies. Whilst Auto Union's technical policy was quite openly based on its member-companies' traditions, There was a move towards greater sharing of components between the brands. By 1935 all technical development had been transferred to the new Central Design Office and Central Experimental Department in Chemnitz, where the Audi 920, DKW F9, Wanderer Types 23 and 24 and the Horch 930 S were developed. A fascinating aspect of the Central Experimental Department was the existence of a thoroughly modern crash testing program, with simulated front and side collisions and a lateral rollover test.