Interior design, technology and ADAS for the Mercedes-Benz B-Class 

Since the launch of the Mercedes-Benz B-Class in 2005 as a sports compact tourer, the automaker has sold more than 1.5 million models worldwide. And consumer demand has remained strong since deliveries of the third-generation B-Class began last year.  

So what is it all about? "More practical than ever, more chic than ever," is how Britta Seeger, Member of the Board of Management of Daimler AG, responsible for Mercedes-Benz Cars Sales, characterises the B-Class. "MBUX – the new Mercedes-Benz User Experience – provides also the B-Class with an all-new customer experience with functions that were previously the reserve of the luxury class." 

The designers' brief was to make the B-Class stand out visually from the world of minivans. In terms of its dimensions, it has a long wheelbase (2729 mm) with short overhangs, slightly lowered roofline and larger, 16- to 19-inch wheels. The relatively squat, progressive front end with flowing transition from bonnet to A-pillar and on to the windscreen, along with the muscular shoulder of the body, gives it a sporty look, especially in AMG body styling. 

So far so good. Let's take a look inside. 

As we would expect from Mercedes, the cockpit incorporates some classy materials and smart gadgets to define the luxury carmaker's interior style. Facing the driver are two displays that can be merged to form a widescreen effect. Supplied by Continental, the dual display is said to make information and other content "intuitively perceptible". One display replaces the conventional instrument cluster and its analogue instruments while the other display sits above the centre console. Touch-sensitive controls on the multifunction leather steering wheel worked quite well to operate both displays. Our press review AMG Line model included an augmented reality navigation system.

The touchscreen is part of the integrated MBUX touch-control concept – a trio consisting of touchscreen, touchpad on the centre console (optional) and touch controls on the steering wheel. The touchpad is a bit fiddly to use at first but you soon get used to it.

Beneath the swanky widescreen display (one half of which is a touchscreen) in the centre of the dash are three round air vents modelled on aeroplane turbines. Combining these chrome vents with the multi-coloured ambient lighting package provides showroom appeal in spades.

Lower down on the centre stack is a row of switch-like buttons to control the HVAC and certain driving assistance systems.

Among those supplying the B-Class, AGC Automotive supplies the glazing. Chinese automotive company Ningbo HuaXiang Electronic and Hib Rolem Trim, a German-Romanian automotive supplier, produce auto parts and accessories, for example, decorative items for interior parts such as dashboards, centre consoles, and door trims for the A- and B-Class cars. 

The power-adjustable, heated Artico man-made leather seats are offered with a massage function. The front seats also feature a kinetic system, enabling minuscule adjustments to the angle of each seat and backrest for either long or short journeys. The front seats are operated via intuitive pictogram buttons located on the door panels. The seat geometry and lower beltline provide a decent feeling of space compared to the previous model. The driver sits 90 millimetres higher than in an A-Class, providing a slightly lofty and reasonably comfy perch. Visibility is quite good thanks to optimised cross-sections of the roof pillars, which obscure less of the surroundings. 

The roomy rear seating area has ample headroom (despite the double sunroof) and foot space beneath the front seats. With the rear seat folded down, the flat luggage area can accommodate up to 1540 litres. A folding backrest of the front passenger seat provides an even longer loading length. 

The powered tailgate can be operated by either pressing a button on the driver's door panel, boot lid, key fob, waving your foot under the rear bumper (if you have ticked that option) or simply by manually releasing the boot handle. 

The B-Class is the second car model after the A-Class to feature the MBUX system, which ushered in a new era with Mercedes me Connectivity. Its ability to learn thanks to AI makes the system unique.

The 'Mercedes me connect' can assist vehicle diagnostics in the event of a breakdown or an accident. Its concierge service sorts out the finer things in life, such as making a restaurant reservation, obtaining tips about tourist routes and information on cultural and sporting events. It can also send navigation destinations directly to the car.

The B-Class is also set up for private car sharing. 'Mercedes me' allows the car to be shared with friends and family members using an app.

Cloud-based voice activation ('digital assistant') is operated via a button on the steering wheel. Voice commands are somewhat limited but seemed to work well, all things considered. There is no shortage of USB sockets front and back to power up mobile devices. 

During night-time driving, the B-Class takes on an entirely different feel thanks to the ambient interior LED lighting that can be personalised using a palette of no fewer than 64 colours. It really does start to feel like a cockpit, adding illuminating highlights to the trim, central display, front stowage compartment on the centre console, handle recesses, door pockets, front and rear footwells, overhead control panel and even the door sills.

Many of the driving assistance systems fitted to the B-Class are carried over from the S-Class. Just like the S-Class, the B-Class can be driven semi-autonomously in certain situations. Using camera and radar systems, it can anticipate traffic up to 500 metres ahead while using map and navigation data for assistance functions. For example, Active Distance Assist Distronic as part of the driving assistance package is able to support the driver in many route-specific situations, predictively and conveniently adjusting the speed, e.g. when approaching bends, junctions or roundabouts. Also on board are Active Emergency Stop Assist and Active Lane Change Assist. Other ADAS technologies include Active Brake Assist, which can help mitigate the severity of rear-end collisions with slower-moving, stopping or stationary vehicles ahead. While the driver assistance pack is one of the most comprehensive available, it occasionally interferes – via audible warnings, adjusting the steering or brakes - when no real road danger exists.

The 2.0-litre diesel in AMG Line that we took out felt easy-going and relaxing along motorways and rooted on twisting back roads. Power is managed by an eight-speed automatic gearbox providing a good response when required. The gearbox, known as 8G-DCT which is short for eight gear double-clutch transmission, is produced at Daimler's factory in Sebes, central Romania. The ride was also smooth at doing its job (people carrying) on 18-inch multi-spoked wheels thanks to Tenneco's clever electronic damper technologies. The car's large fuel tank gave a good range and returned an average 49.1 mpg, a touch short of the carmaker's 50.4 mpg claim. 

On balance, the B-Class comes with a generous list of standard equipment, oodles of connectivity, clever safety technology and an intuitive infotainment system. The net result of all this fashionable interior, high-end equipment and fancy screens makes it a good place to spend time. 

For the first time, the B-Class is able to drive semi-autonomously in certain situations. The B-Class can see up to 500 metres ahead due to its camera and radar systems. The B-Class also uses map and navigation data for assistance functions. For example, Active Distance Assist DISTRONIC as part of the Driving Assistance Package is able to support the driver in numerous route-specific situations, and predictively and conveniently adjust the speed e.g. when approaching bends, junctions or roundabouts.

The driver is also able to see at a glance which assistance functions have been selected, and to which situations the systems are reacting at present. Display icons – e.g. a steering wheel with hands on both sides, signalling that both hands should be on the steering wheel – give information both on the screen and in the Head-up Display. All the driving assistance functions can be operated via the steering wheel. 

Active safety as standard: extended Brake Assist 

The B-Class comes as standard with extended Active Brake Assist. Depending on the situation, it can effectively help to mitigate the consequences of rear-end collisions with slower-moving, stopping or stationary vehicles ahead, and even with crossing pedestrians and cyclists, or prevent them altogether. If the distance drops significantly below the safety threshold, the system issues a visual warning to the driver. If it detects a serious risk of collision, the driver receives an additional, audible warning. It also computes the brake pressure required to prevent a collision, if this is still possible.  

If, having been warned, the driver then steps on the brake pedal, the system is capable of boosting insufficient braking pressure in line with the needs of the situation. In so doing, it makes the best possible use of the remaining distance in order to leave the vehicles behind room to brake. If the driver fails to respond, Active Brake Assist can go one step further and brake autonomously if the danger of collision persists, so as to mitigate the severity of the accident or in the best case even prevent it. 

Attention assist with adjustable sensitivity, which can warn the driver in a timely manner of inattentiveness and drowsiness, is also included as standard. 

Modular driving assistance system: support according to preference 

The B-Class offers a modular range of driving assistance systems. In addition to the already extensive standard equipment specification, optional extras right up to the Driving Assistance package also make it possible to individually configure the vehicle with respect to driving assistance. Active Distance Control DISTRONIC is individually available for comfortable longitudinal control, and in conjunction with traffic sign recognition this allows manual adoption of recognised speed limits.

Already in its purely advisory version, at low speeds the Blind Spot Assist is capable of warning of vehicles, including bicycles, in the danger area. When the vehicle is at a standstill it can signal to the driver with a visual warning in the exterior mirror before they climb out that a vehicle is driving past in the critical area. If the driver uses the door handle at this moment, an additional acoustic warning sounds. The vehicle driving past or the cyclist cycling past must be moving at more than 2 m/s. The function is also available when the vehicle is stationary and up to three minutes after the ignition has been switched off. Blind Spot Assist can be extended with Active Lane Keeping Assist which, already in the basic variant, is capable of warning against unintentional lane departure by vibrating the steering wheel and, if the driver crosses a solid line, of correctively intervening by means of one-sided braking action.

The functionality of Traffic Sign Assist has been expanded by a wrong-way warning function which now not only warns against wrong-way entry onto the motorway, but also of wrong-way entry into one-way streets. In addition, the detection of stop signs has been coupled with the ECO start/stop function, and is suitably taken into consideration by the latter – the engine remains on. In combination with the driver assistance package (see next paragraph), it is also possible to warn against people in zebra crossing areas.

Driving Assistance package: Many important assistants 

The assistance and safety systems are grouped together in the Driving Assistance package (optional equipment). The individual functions in detail are described below. 

Active Distance Assist DISTRONIC with Active Steering Assist: Within a speed range from 0 - 210 km/h, and on all types of road – motorway, country road or in urban areas – the system is not only able to automatically maintain the desired distance from the vehicle ahead, but also to give the driver noticeable steering assistance, even on bends. At speeds up to 130 km/h the system is not necessarily dependent on clearly visible lane markings as it can also actively provide support if the lines on the road are unclear, as is often the case at road works, or even if there are no lines on the road at all. The system therefore makes driving much easier and offers support, especially in bumper-to-bumper driving or tailbacks.

The reduction in speed takes place in varying degrees, depending on the selected DYNAMIC SELECT driving mode (e.g. SPORT, COMFORT or ECO). Active Distance Assist DISTRONIC controls the distance from the vehicle ahead within a speed range from 0 to 210 km/h, and keeps the car on track. Coasting characteristics, e.g. on downhill slops, can now also be taken into account.

Active Speed Limit Assist: In conjunction with MBUX, Active Speed Limit Assist - an engageable subfunction of Traffic Sign Assist - is also able to recognise sign gantries and road works signs by camera. Known limits, such as 50 km/h in built-up areas or 100 km/h on country roads, are also adopted from the navigation system. Active Distance Assist DISTRONIC adapts the vehicle's speed to the recognised speed limits automatically (in combination with navigation and traffic sign recognition). In this case, the speed can be anticipatorily adapted when entering towns based on map data. On roads without speed limits, such as stretches on German motorways, the recommended speed – in this case 130 km/h - is adopted as the set speed. This speed can be adjusted by the driver. The desired maximum speed is always adopted in the course of the journey when the speed limit is cancelled. It remains preset until the vehicle leaves the motorway or until the engine is switched off.

Following vehicles in a tailback: in stop-and-go traffic on motorways and similar roads, stops of up to 30 seconds are now possible within which the B-Class automatically moves off and follows the traffic ahead.

Active Lane Change Assist: When the driver wishes to change lanes on multi-lane roads (recognised by the navigation system) at speeds from 80 to 180 km/h, it is now sufficient to nudge the indicator stalk to activate support. Within the next ten seconds, the sensor system checks together with the driver whether the next lane is clear in front of, alongside and behind the vehicle, also taking into account the speed of any other vehicles. If there is no other vehicle within the relevant safety zone, the driver is supported in changing lane. The initiated lane change is indicated in the instrument cluster and in the head-up display. The system is available in certain countries, depending on certifiability.

Active Emergency Stop Assist: Active Emergency Stop Assist brakes the vehicle to a standstill in its lane if it detects that the driver is no longer actively driving the vehicle while it is on the move with Active Steering Assist switched on. If there is no steering wheel movement over a longer period when Active Steering Assist is active, the system gives the driver a visual and audible prompt to place their hands on the wheel. If the driver fails to respond after repeated visual and acoustic warnings by moving the steering wheel, accelerating, braking or operating the touch controls or other buttons on the steering wheel, the car is slowed down in the identified lane until it comes to a standstill. At speeds below approx. 60 km/h the traffic behind is warned by means of hazard warning lights. When the vehicle comes to a standstill, the parking brake is engaged automatically and the Mercedes-Benz emergency call system is activated. The vehicle is also unlocked, to allow first responders access to the interior. The functions are aborted as soon as the driver takes control of the vehicle again.

Active Brake Assist: Active Brake Assist with cross-traffic function is able to help the driver avoid impending collisions with vehicles ahead, stationary or crossing vehicles and with people if the driver fails to take any action to defuse the dangerous situation. This assistance takes the form of a distance warning from a warning lamp in the instrument cluster, if the distance from a vehicle in front is insufficient an additional acoustic warning if the danger of collision is identified braking assistance appropriate to the given situation as soon as the driver applies the brakes autonomous emergency braking to avoid a collision with moving, stationary or crossing vehicles ahead if the driver fails to respond autonomous emergency braking also for stationary or crossing pedestrians/cyclists.

Evasive Steering Assist: Within a speed range from 20 to 70 km/h, Evasive Steering Assist can help the driver to avoid a pedestrian detected by the assistance system using the radar sensors and stereo multi-purpose camera. If the driver initiates an evasive manoeuvre by turning the steering wheel, the system provides assistance by adding precisely calculated steering torque to support the movement of the steering wheel. This torque helps the driver to avoid the pedestrian in a controlled manner and then makes it easier to straighten the vehicle up again so that it can drive past safely. While the philosophy behind Evasive Steering Assist is to provide the driver with significant assistance, the initiative to take evasive action must come from the driver. This is because if evasive action were automatic, a previously inattentive driver might be so surprised by the spontaneous movement of the steering wheel that they might react incorrectly and, for example, attempt intuitively to steer in the opposite direction. 

Active Lane Keeping Assist: This system is able to warn the driver by means of pulsed vibrations at the steering wheel when the vehicle is unintentionally drifting out of its lane at speeds between 60 and 200 km/h. If the vehicle passes over a continuous line, it can pull the vehicle back into lane by applying the brakes on one side. In the case of a dotted line, such intervention takes place only when there is a danger of collision with a vehicle in the adjacent lane (including danger from oncoming traffic). 

Active Blind Spot Assist: In the speed range from approx. 12 to 200 km/h, this system is able to provide the driver with a visual alert plus an audible alarm when a turn indicator is actuated, to warn of a danger of side collisions with other vehicles, including bicycles, for example. At standstill this exit warning also works when leaving the vehicle, enabling e.g. collisions with cyclists to be avoided when opening a door. At speeds above 30 km/h, automatic braking on one side of the vehicle can help avoid a side-on collision at the last moment. 

Traffic Sign Assist: Image recognition and information from the digital road map in the navigation system allow the permitted maximum speed and any restrictions on overtaking for the current route section and zebra crossings to be computed and shown in the instrument cluster. Additional restrictions such as speed limits in wet conditions (warning when the windscreen wipers are switched on) or speed limits for trucks only are also taken into account or ignored as appropriate in the individual case concerned. The vehicle speed is compared with the speed limit. If set to do so by the driver, a visual/visual-audible warning is given if the speed limit is exceeded. No-entry signs are also recognised and the driver is prompted to check the vehicle's direction of travel. A warning additionally appears in the instrument cluster and on the head-up display if pedestrians are detected in the area of a zebra crossing. Traffic Sign Assist is also separately available outside the assistance package.

PRE-SAFE PLUS: Protection against danger from the rear 

PRE-SAFE PLUS can intervene when following traffic presents a danger. To this end the radar sensors in the rear bumper monitor following traffic to detect an impending rear-end collision. If a hazardous situation is detected, the system warns drivers of the vehicles following behind of the risk by flashing the hazard warning lights at a faster frequency. It also pre-emptively initiates PRE‑SAFE occupant protection measures, especially the reversible belt tensioners. If the vehicle is at a standstill, PRE-SAFE PLUS also applies the brakes firmly. This reduces the forward jolt from the impact, considerably lowering the loads acting on the occupants and the risk of whiplash injuries. Moreover, locking the brakes can prevent secondary collisions e.g. on junctions with crossing pedestrians or a vehicle ahead.

Child safety: automatic deactivation of the front passenger airbag 

A pressure sensor in the front passenger seat surface can detect whether the seat is unoccupied or whether an infant seat or other child seat is placed on the passenger seat. For a child seat facing backwards, the front passenger airbag is deactivated automatically, while for a child seat facing forwards it depends on the weight. Contrary to other systems that require the airbag to be deactivated with a key, this system reduces the risk of incorrect operation. A special transponder is not required. The system is standard or optional equipment depending on the market or region. 

Jump into a new car today and you are almost sure to find a tablet-style touchscreen infotainment system positioned centre stage of the dash. It acknowledges that most of us no longer use maps to find our way around but expect the car to guide us to our destination and remain connected throughout the journey. For example, the Volvo XC90 comes loaded with semi-autonomous and connected car features, most of which are displayed on an intuitive centre console touchscreen.

As with most new technologies, what starts in the luxury market often trickles down the car segments. Inside the new Honda Civic, positioned at the top of the piano-black finish centre console - and drawing the eye as the push start is pressed - is a Honda Connect 2 seven-inch touchscreen, serving as the main point of contact to control the infotainment and climate control functions. This second-generation of Honda’s infotainment and connectivity system incorporates Apple CarPlay and Android Auto integration.

Tomorrow’s cockpits, according to Harman, will have more curved screens designed using OLED technology. The main advantage of an OLED display is that it works without a backlight, enabling it to blend into the interior.

Screens are becoming larger, too. The Tesla Model S features a huge 17-inch screen. But that is just the tip of the iceberg. China’s Byton has debuted its first concept car. A notable feature of the electric SUV is a colossal 49-inch screen stretching the width of the dash.

Whether or not such high-tech wizardry will actually make it onto the road, the above concepts demonstrate the direction the auto industry is taking.

While giving instructions in our cars is nothing new, putting questions to the likes of Alexa and Cortana while on the road is. Automakers are fast adopting virtual assistants, confirming that speech is becoming the preferred interface for tomorrow’s cockpit.

Voice recognition is seen by some as the answer to eliminate many controls that have traditionally been manually operated. Voice can play an important part of a multimodal HMI solution for inputting information or for cutting through layers on the menus by requesting a function directly. Traditional voice control was centred on a set of fixed commands with catatonic responses which required some level of driver training prior to operation of the system. With the advent of the new low power, high performance microprocessors, smarter voice command engines linked into the HMI logic are now available. Even natural language and grammatical analysis are becoming more achievable.

Voice recognition, although already an option, looks set to play a bigger role as cars gradually become more autonomous.

Looking down at a touchscreen (without haptic feedback) can be distracting. Gesture recognition is therefore said to be the Next Big Thing, regarded as the logical next step from touchscreens and buttons. Gesture control operates via a stereo camera within the cabin that can recognise certain hand movements for pre-programmed adjustments and functions. Rotating your finger clockwise at a screen could turn up the volume or a finger gesture could answer or decline a call. While such novelties will make life simpler for the driver, it should also simplify interior design and liberate space for storage options.

Advances have also been made in the interior lighting department. Not so long ago, interior lighting consisted of central and side headliner lights, complemented by low-level ambient lighting located mainly in the cockpit area. Today, the accent has changed, thanks to widespread use of LEDs enabling personalisation of car interiors. For example, during night time driving, the Mercedes-Benz E-Class takes on an entirely different feel thanks to the ambient interior LED lighting that can be personalised using a palette of no fewer than 64 colours. It really does start to feel like a cockpit, adding illuminating highlights to the trim, the central display, the front stowage compartment on the centre console, handle recesses, door pockets, front and rear footwells, overhead control panel and mirror triangle.

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