Despite its overall length of 13,890 millimetres, the S 431 DT´s turning circle is a
mere 22,760 millimetres due to the wheelbases, overhangs and hydraulic power-assisted steering. The third axle, a ZF trailing axle with Rear Axle Steering (RAS) system, improves manoeuvrability. At steering angles of more than 5°, the trailing axle is positively steered; it remains active up to maximum speed and also when reversing. This is an additional safety factor as the trailing axle performs a lateral guidance function in all driving conditions, for example when avoiding an obstacle.

The Bus is equipped with a Mercedes-Benz OM 502 LA engine developing 370 kW (503 hp) and the automated ZF-AS Tronic 12-speed manual transmission, and meets the Euro 5 emission.

The S 431 DT is equipped with the Electronic Brake System (EBS) with a standard braking assistant, which features short response times, braking distances and permanent system monitoring; it dramatically increases overall safety . The EBS also controls the trailing axle. When the vehicle is braked, this axle is included with individual control and a separate axle modulator. The Integrated Electronic System (IES) for engine and driveline/brake management, with improved matching of engine, transmission and brakes by way of data communications, also plays an important role here.

The ergonomically designed driver´s work area with an additional 80 millimeters of rearward movement for the driver´s seat is also part of the safety package. The air-sprung seatÕs total adjustment range is 200 millimetres. The TopClass 400´s clearly laid-out cockpit has plenty of and storage space for items needed by the driver. The navigation monitor, the radio and audio and video controls and the tachograph are all within easy reach. The joystick gear shift is an outstanding feature for convenient gear selection that simplifies handling of the double-decker. The cockpit with its optimized seat and grab handle positions allows fatigue-free driving.

The driver place