The new A-Class has the very latest driving assistance systems with cooperative driver support, giving it the highest level of active safety in this segment with functions adopted from the S-Class. For the first time, the A‑Class is able to drive semi-autonomously in certain situations.
The new A-Class has an eagle-eye on the traffic situation: improved camera and radar systems allow it to see up to 500 m ahead. The A-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. Clearly understood 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 new A-Class comes with extended Active Brake Assist as standard. Depending on the situation, this 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 A-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 in the navigation system 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. For the first time, 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 object driving 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 extended to include, for example, a warning of pedestrians near zebra crossings, and an extended wrong-way warning function which is now not only able to warn against wrong-way entry into motorway slip roads, but can also warn against driving the wrong way into a one-way street or onto a roundabout. 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.
Driving Assistance package: numerous assistance systems usefully combined
The assistance and safety systems are grouped together in the Driving Assistance package (optional equipment). The individual functions in detail:
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 correct 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 intervene actively 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, 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). This means that semi-automated driving for longer periods is also a reality on country roads. 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 certain cases, the speed can be adapted in anticipatory mode on the basis of 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 A‑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. 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 his/her hands on the wheel. If the driver fails to respond after repeated visual and acoustic prompts, either by moving the steering wheel, accelerating, braking or by pressing the touch control button 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 broken line, such intervention takes place only when there is a danger of collision with a vehicle in the next 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. This exit warning is being used for the first time in the A‑Class and at standstill this also works when leaving the vehicle, enabling, for instance, collisions with cyclists to be avoided when opening a door. At speeds above 30 km/h, the Driving Assistance package can also automatically apply one-sided braking action to help avoid a side 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 dangerous situation is recognised, the system warns the driver of the vehicle behind by operating the hazard warning flashers at increased frequency (not in USA/Canada). 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.
Easier parking and manoeuvring: further assistance systems on request
Active Parking Assist with PARKTRONIC assists the driver when searching for a parking space and when entering or leaving parallel or end-on parking spaces. In the case of end-on parking spaces it is active in both forward and reverse direction. It manoeuvres the vehicle into the selected parking space and back out again. In the process, acceleration, braking and gear-changing is automatic if the 7G-DCT dual clutch transmission is installed. In combination with Blind Spot Assist, the system can warn the driver of cross-traffic when reversing out of end-on parking spaces, and also initiate automatic braking if necessary. PARKTRONIC gives a visual and acoustic warning of recognised obstacles with the help of six ultrasonic sensors in each bumper. These can be in front of, to the side or behind the vehicle, and are recognised at speeds up to approx. 10 km/h.
The Parking package combines Active Parking Assist with a reversing camera in the boot lid. Its image is shown in diagrammatic form with superimposed guide lines in the MBUX display. The reversing camera is also available separately.
If the Parking package with 360° camera is specified, an all-round view is provided by the 360° camera with four networked close-range cameras in the radiator grille, boot lid handle and exterior mirror housings. The information is clearly presented in selectable views in the MBUX display.