UX Analysis: Mercedes-Benz A-Class ‘MBUX’

The latest Mercedes A-Class features a newly developed user interface system called MBUX, which aims to deliver a step change in automotive interactivity. Our tests in the real world revealed a broadly impressive system, though one that remains complex to operate. A full day behind the wheel took us only part-way along the required learning curve.

Not every A-Class will boast all the features of MBUX, but we were able to explore the full capabilities in a top-level variant.

The hardware includes two letterbox-format 10-inch digital screens, mounted side by side behind a single glazed surface. A broad gap between the two is presumably intended to fall where the steering wheel bisects the driver’s view, though the geometry won’t work for everyone. We found the wheel rim obscured the nearest fifth of the centre screen.

The centre display is a multi-touch screen, and user input is also collected via thumb-operated control clusters on the steering wheel spokes. The left cluster controls the left screen, and vice versa. Each cluster includes its own home key, back button and a miniature trackpad called an ‘optical finger navigation’ (or OFN). The OFN accepts swipes and clicks.

There is also a palm-sized trackpad mounted on the centre console, which by default provides both audible and haptic feedback when swiped, as well as when clicked.

As the hardware suggests, most functions can be controlled in multiple ways, with voice control via eight cabin microphones offering another option.

On-screen graphics are crisply drawn and move with remarkable fluidity, though the graphical design is quite fussy and skeuomorphic in places – seeming dated as a result. The data shown on both screens is highly configurable and there is an “Understated” graphics option, but there’s no way to choose a flatter style of presentation.

Touchscreen interaction will come naturally to anyone familiar with a smartphone. From the home screen, the major options are laid out in a 2D matrix of app-like icons. The layout can be explored by swiping left-to-right or up and down, with apps launched by a quick prod. The icons are large and the area that will activate each one is broad, to help keep eyes on the road. Icons can also be reordered with a long press and drag.

Overall, the style of interaction feels very natural and tends to avoid the need to clamber around menu structures to find the option sought.

Interestingly, the trackpad and OFNs have been set up to act like a mouse. As a result, a swipe left on the touchscreen will have the opposite effect to a swipe left on the trackpad. This can feel disconcerting at first.

“We changed this direction a lot of times, because there were different people expecting different things,” admits Andreas Bauerfeld from Daimler’s MBUX development team. Oddly, given this divisive result, there’s no user-selectable option to flip the direction of trackpad operation.

The touchscreen and main trackpad both support multi-touch interaction, so you can pinch to zoom or rotate a map by twirling two fingers. A double swipe will quickly summon an audio control panel, whatever else the screen might be doing.

The home screen also includes a global search function, which will make intelligent guesses during user input, searching through available controls, music titles, phone contacts, sat-nav destinations and the car’s digital owner’s manual. Inputting text is done via voice recognition, on-screen keyboard or by spelling out letters on the trackpad – the latter being a lot trickier if the trackpad falls under your less dextrous hand.

With so many configurable options, Mercedes has wisely created personal profiles. Bauerfeld says each profile can hold about 900 parameters, storing on-screen software options as well as hardware settings such as mirror positions.

If you switch on a car with multiple stored profiles, the car will prompt you to choose one at the outset, and Bauerfeld says profiles can also be uploaded and downloaded to transfer them from car to car. He adds that MBUX will also try to learn who is who, to pop the right option at the top of the list.

Users can set up favourite controls, which appear as icons on the home screen. “If you find something that takes several inputs, but you need it often, for example turning off surround lighting, you can use a long press and send it to favourites,” Bauerfeld explains. “You can always access favourites via the [home] button, which makes it fast.”

Optionally, MBUX will keep track of user actions and start to make suggestions. “They might include satnav destinations or call lists,” Bauerfeld says. “If you normally call someone at six o’clock every day, it will suggest that – but it won’t actually call them.”

A single user can also set up multiple themes – perhaps sporty and relaxed settings – and store them as favourites. This creates the potentially annoying possibility for the front passenger to press one icon and completely reconfigure the car, including the screen in front of the driver.

Mercedes has tried to intercept some other likely sources of family strife. “You can say, ‘Turn the seat heating on’; or ‘I’m cold’ and it will turn up the heating, but you can’t command safety features,” says Bauerfeld. “Imagine you’re in the carwash and your kid says, ‘Open all windows’ – it won’t do that.”

Voice control is accessed via a quick button press or simply saying “Hi Mercedes.” In action, it copes well with onboard functions and some general questions, such as looking up tomorrow’s weather, though it also shows surprising gaps. When asked the distance to particular town, it gave up, whereas Apple’s Siri fetched the correct answer in a jiffy…

One helpful or perhaps gimmicking feature is the option of augmented reality directions. On the approach to junctions the centre screen will show a camera view of the road ahead, overlaid with blue arrows pointing out the road to take.

Some MBUX features require knowledge rather than intuition – a long press of the home key will reset the instruments to their standard layout, for example – but in most instances it’s possible to grapple with MBUX by guesswork. It’s also pleasing to see how rarely the software presents an OK/cancel dialog box.

The software is admirably quick and smooth, both in operation and in loading up from cold. Surprisingly, software loads from a hard disk rather than solid-state storage.

Bauerfeld says future iterations of MBUX – presumably in more upmarket cars – will get SSD storage, but adds that the data input and output have been highly optimised to boost speed. As little data as possible is moved to and fro from the hard disk. Too many automakers, he adds, make users wait while gigabytes of rarely used functions are loaded into active memory.

Overall, MBUX embodies a thoughtful, well considered approach to in-car interaction. But there is still no shortage of room for improvement.