The Volkswagen Beetle (officially the Volkswagen Type 1, informally in Germany the Volkswagen Käfer, in Poland the Volkswagen Garbus and in the U.S. the Volkswagen Bug) is a two-door, four passenger, rear-engine economy car manufactured and marketed by German automaker Volkswagen (VW) from 1938 until 2003. The need for this kind of car, and its functional objectives, was formulated by the leader of Nazi Germany, Adolf Hitler, who wanted a cheap, simple car to be mass-produced for his country's new road network. Hitler contracted Ferdinand Porsche in 1934 to design and build it. Porsche and his team took until 1938 to finalise the design. The influence on Porsche's design of other contemporary cars, such as the Tatra V570 and the work of Josef Ganz remains a subject of dispute. The result was one of the first rear-engined cars since the Brass Era. With 21, 529, 464 produced, the Beetle is the longest-running and most-manufactured car of a single platform ever made. Although designed in the 1930s, the Beetle was only produced in significant numbers from 1945 on (mass production had been put on hold during the Second World War) when the model was internally designated the Volkswagen Type 1, and marketed simply as the Volkswagen (or "People's Car"). Later models were designated Volkswagen 1200, 1300, 1500, 1302 or 1303, the former three indicating engine displacement, the latter two derived from the type number. For 1974, North American models received newly required 5 mph (8.0 km/h) impact bumpers mounted on self-restoring energy absorbers, which added approximately (25 mm (0.98 in) to the car's overall length. On the Super Beetle, the steering knuckle, and consequently the lower attachment point of the strut, was redesigned to improve handling and stability in the event of a tire blowout. A limited-edition Big Beetle was introduced based on the 1303 LS. Available in unique metallic paint colors, the car featured styled-steel 5.5 in (140 mm) wide sport wheels.