addition to cameras and ultrasonic sensors for their AI. Bodyshells Audi produces 100% galvanised cars to prevent corrosion, and was the first mass-market vehicle to do so, following introduction of the process by Porsche, c. 1975. Along with other precautionary measures, the full-body zinc coating has proved to be very effective in preventing rust. The body's resulting durability even surpassed Audi's own expectations, causing the manufacturer to extend its original 10-year warranty against corrosion perforation to currently 12 years (except for aluminium bodies which do not rust). Space Frame Audi introduced a new series of vehicles in the mid-1990s and continues to pursue new technology and high performance. An all-aluminium car was brought forward by Audi, and in 1994 the Audi A8 was launched, which introduced aluminium space frame technology (called Audi Space Frame or ASF) which saves weight and improves torsion rigidity compared to a conventional steel frame. Prior to that effort, Audi used examples of the Type 44 chassis fabricated out of aluminium as test-beds for the technique. The disadvantage of the aluminium frame is that it is very expensive to repair and requires a specialized aluminium bodyshop. The weight reduction is somewhat offset by the quattro four-wheel drive system which is standard in most markets. Nonetheless, the A8 is usually the lightest all-wheel drive car in the full-size luxury segment, also having best-in-class fuel economy. The Audi A2, Audi TT and Audi R8 also use Audi Space Frame designs. Drivetrains Layout For most of its lineup (excluding the A3, A1, and TT models), Audi has not adopted the transverse engine layout which is typically found in economy cars (such as Peugeot and Citroën), since that would limit the type and power of engines that can be installed. To be able to mount powerful engines (such as a V8 engine in the Audi S4 and Audi RS4, as well as the W12 engine in the Audi A8L W12), Audi has usually engineered its more expensive cars with a longitudinally front-mounted engine, in an "overhung" position, over the front wheels in front of the axle line - this layout dates back to the DKW and Auto Union saloons from the 1950s. But while this allows for the easy adoption of all-wheel drive, it goes against the ideal 50:50 weight distribution. In all its post Volkswagen-era models, Audi has firmly refused to adopt the traditional rear-wheel drive layout favored by