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The new Setra S 531 DT impresses with light handling and superior driving characteristics

The press trial drive of the fourth generation of the Setra double-decker S 531 DT is taking place in Valencia in Spain and takes in around 150 kilometres along the coast as well as into the mountainous region behind.

Despite its considerable size, the modern and dynamic design which makes use of elements from both of the latest Setra touring coach model series dispels any possible menacing air from the 14-metre-long coach.

As soon as they climb aboard via the wide entrances, driver and passengers are welcomed by soft curves and elegant shapes. As on all of the models of the 500 series, a door for the driver is no longer provided, thus enabling the driver's seating position and stowage options to be optimised even further. Thanks primarily to the newly designed exterior mirrors which extend further forward, the driver is able to retain an overview of the large vehicle body at all times even when sitting in a normal, upright position.

Overall the positive first impression in the driver's seat is one of an enhanced sense of space and further improved ergonomics. Irrespective of whether operators select the luxurious cockpit from the TopClass 500 or the functionally designed cockpit from the ComfortClass 500 – they always receive an ergonomically refined workplace for their drivers with a host of stowage facilities and in which all of the controls are arranged precisely where they are expected to be. The easy-to-handle multifunction steering wheel finished in high-quality leather provides direct access to the most important functions via the intuitive Stacks&Cards menu which is familiar from all of the vehicles of the 500 series and as such is very straightforward to use. The market-leading Coach Multimedia System is also always available on board: it enables the commercial vehicle to dispense with a touchscreen and can always be operated flawlessly thanks to two large rotary knobs.

The ignition lock for the high-tech key is now located on the left of the steering wheel. A gentle press on the engine button brings the 12.8-litre OM 471 six-cylinder in-line engine in the rear of the double-decker to life. With its output of 375 kW (510 hp) and a full 2500 Nm of maximum torque, it drives the touring coach in a manner which is as forceful as it is effortless, without ever sounding intrusive. But it is not only in the cockpit where the new Setra boasts a low noise level - in the rear of the top deck, too, dream values of less 60 dB(A) are recorded at cruising speed. Wind noise in the cockpit is just as insignificant as the audible signs of life from the front axle – an enhancement of the familiar Setra independent suspension with Mercedes-Benz wheel head. In conjunction with the precise yet light steering, the biggest Setra provides an incomparably superior driving experience.

The 80% tyres used by Setra for its double-decker buses for many years not only contribute to the high levels of comfort but are also compatible with current fleet equipment. Thanks to the electrohydraulically steered trailing axle, tight curves are just as easy to negotiate as roundabouts for the vehicle with its relatively compact turning circle of 23.1 m. The smooth and precisely shifting GO 250-8 fully automated eight-speed transmission makes its own particular contribution to the enjoyment of the smooth, jerk-free forwards propulsion. If somewhat more rapid progress is ever called for, the engine speed can be increased by around 200 rpm up to the speed for shifting up in the selectable dynamic mode at any time. Manoeuvring is also an easy task thanks to the transmission's sensitive, automated clutch work as well as the bright LED docking lights in front of the rear double axel.

The most comprehensive range of safety and assistance systems on the market quickly convinces the driver that they are in control of one of the safest touring coaches ever. This is evident not least from the fact that the road is illuminated as standard by the new LED headlamps: they feature a colour temperature which is close to daylight as well as a long service life. As a result, fatigue-free visibility is guaranteed at all times. Nevertheless, should the driver ever suffer from dwindling levels of attention, the Attention Assist system subtly but forcefully gives him a visual, audible and haptic warning.

The adaptive cruise control (ART) with Stop&Go function and also the new emergency braking system ABA 4 additionally convey an initial impression of what autonomous driving could soon come to mean. When moving back in after overtaking, support is now provided by the Lane Changing Assist function of the new Sideguard Assist which has two close-range radar sensors behind the front axle. Along with ABA 4, the system is celebrating its world premiere and is primarily active when it detects fixed obstacles or even people in the right-hand turning area of the bus.
The driver is notified of the impending danger by means of a multi-stage sequence of warnings, however, he retains responsibility for control at all times. Emergency Brake Assist ABA 4 with its modern multi-mode radar sensors is now able to detect pedestrians and initiate braking automatically when there is the risk of a collision. The enlarged beam angle of the radar sensors of 120 degrees at close range is clearly noticeable by the fact that barely anything or anyone is able to evade the system. If an assessment classification for pedestrian protection existed, similar to the Euro NCAP test for passenger cars, this bus would certainly have earned a five-star rating.
An initial impression of driving a double-decker would not be complete with a few words about the two-fold passenger comfort - but this is, in fact, the unique selling point of a double-decker. Whether it's the communication-friendly seating groups with chic tables in the lower deck, the spacious, easily accessible toilets at ground level, the generously sized kitchenette or the much sought-after first row in the top deck – these unique equipment features lend the latest Setra double-decker a very special, unparalleled sense of flair in the bus segment.
The designers paid particular attention to the cockpit in the first row: visually appealing and with a functional design, the comfortable passenger seats in the first row, produced in-house, must be among the most sought-after seats in the S 531 DT – just like the two workplaces for the driver and tour guide located directly beneath them.