Maximum efficiency and variability, supreme comfort and the ultimate in safety: the new Setra S 531 DT double-decker bus of the TopClass 500 sets new standards in its class. With superlative aerodynamics, this impressive touring coach is all set to establish new fuel efficiency records in its segment. With its flexible lower deck, it covers the entire scope of applications in touring and regular services. The interior boasts an impressive standard of comfort. Finally, the use of Active Brake Assist 4 and Sideguard Assist on board the new double-decker bus will mark the world premiere for these assistance systems in the bus and coach segment. These systems further enhance the already high standard of safety. All this is cloaked in a fascinating design with its own distinct stamp.