The optional Driving Assistance package consists of DISTRONIC PLUS, BAS PLUS, PRE-SAFE® brake as well the Lane Keeping Assist and Blind Spot Assist systems. The DISTRONIC PLUS proximity control system helps keep the vehicle at the desired distance from vehicles travelling ahead, operating in the speed range from 0 to 200 km/h. Radar sensors permanently measure the distance, regulate the speed and intervene to brake the vehicle, being able to bring it to a standstill if necessary. If the distance to a vehicle travelling ahead narrows down too fast, the system warns the driver by means of an audible signal, and at the same time it automatically calculates the brake pressure required to avoid a collision. If there is no vehicle travelling ahead, DISTRONIC PLUS acts as cruise control and maintains the pre-set speed constant. The Lane Keeping Assist feature registers lane markings and keeps the vehicle safely in its lane in the event of unintentional steering movements.
The integral ADAPTIVE BRAKE system improves ride comfort and safety by helping to execute critical braking manoeuvres with the ABS anti-lock braking system and making difficult driving situations easier with convenience functions.
These include the HOLD function which acts like a parking brake and can be activated by briefly depressing the brake pedal (and is released again either by briefly depressing the accelerator pedal or by depressing the brake pedal briefly once again). The HOLD function then keeps the vehicle from rolling unintentionally when stopped at a light or in stop-and-go traffic. The hill-start assist prevents the vehicle from rolling back, or forwards unexpectedly, e.g. when pulling away on a slope and changing from the brake to the accelerator pedal. The "brake drying" function ensures that full braking power is available even under wet conditions. And with the "priming" programme the system reduces the response time of the brakes.
The active multicontour seat allows particularly good adjustment to individual seating needs, tunes itself to each driving situation, massages the back muscles and reduces the risk of injury in the event of an accident.
Depending on the steering angle, lateral acceleration and speed the air cushions in the seat side bolsters are tightened pneumatically in two stages such that ideal lateral support is guaranteed even when the driver is employing a very dynamic driving style. After the dynamic function is switched off the previously selected pressure in the side chambers are automatically reset symmetrically.
The massage function prevents the back muscles from becoming tired on long drives. It supports the principle of "dynamic sitting" which is recommended by orthopaedists.
Besides its benefits for health and comfort, the active multicontour seat can also contribute to safety: when PRE-SAFE® is activated, the PRE-SAFE® positioning function automatically moves the front-passenger seat into a position which is favourable in the event of an accident (in conjunction with the optional memory package).
The optional Lane Keeping Assist feature warns the driver by means of a discreet vibration of the steering wheel as soon as he unintentionally drifts across the lane markings which have been registered by the system, and leaves the current lane. If the turn indicator is operated beforehand or the steering wheel is turned with determination, the system assumes that the lane change is intentional and does not emit a warning. The Blind Spot Assist feature warns the driver of the presence of another vehicle in the critical area to the right or to the left of your own car.
The standard ATTENTION ASSIST can warn the driver and suggests taking a break, as soon as it detects signs of driver drowsiness. The system monitors the driver’s behaviour in particular by using a steering angle sensor on the steering column. If it deviates from the previously measured profile, visual and audible warnings are emitted.
The (optional) PARKTRONIC electronic parking aid monitors the front and rear of the vehicle when manoeuvring by means of sensors and warns the driver if there is a risk of collision. If the system identifies an obstacle, it provides a visual signal. Should the distance drop below approx. 35 cm, a short warning sound is emitted. If the vehicle approaches even closer (to less than approx. 25 cm) a continuous signal is heard. PARKTRONIC uses this procedure to make parking safe, even with limited space available.
Parking Guidance helps the driver, not only when parking, but also when looking for a parking space. Because the ultrasonic sensors measure the length of parking spaces parallel to the car automatically at vehicle speeds of 30 km/h or less. If a suitable space is found, Parking Guidance then provides precise directions regarding the correct steering angle as well as the turn-in and turn-back points.
With its optional integrated camera the system recognises traffic signs and shows the specified speed limit on the central display. So in particular for sections of road with continually changing road signs or in construction areas the danger of overlooking the speed limit is reduced.
The optional Night View Assist Plus function helps the driver by reducing the danger of overlooking dangers when visibility is bad. The system works with infrared headlamps and an infrared camera which transmits an image as a clear grey-scale image which is shown in the central display of the COMAND APS multimedia system. Pedestrians can be automatically identified and highlighted in the display. With this option, it is easier to identify people, animals and objects even when visibility is poor.
The Light Package (optionally available) comprises bi-xenon headlamps with variable light distribution for country roads, motorways and for thick fog conditions, as well as automatic headlamp range adjustment. With the additional functions of the adaptive main beam assist feature, the system automatically adjusts the headlamps in a soft transition towards the low-beam setting in the event of oncoming traffic or vehicles travelling ahead. If the road ahead is free, on the other hand, the greatest possible range is made use of - and can be extended from 65 to a maximum of 300 metres. It is no longer necessary to switch back and forth between high and low beam manually. The active light function and the cornering light feature in the foglamps are further components of the package. To make yourself seen - an essential safety aspect. The daytime driving lights and the LED-technology turn indicator lamps draw sufficient attention from other road users, and the integrated headlamp cleaning system reduces to a minimum the soiling of the vehicle's lighting system.
The Brake Assist can provide protection against accidents by recognising emergency braking situations based on the speed with which the brake pedal is depressed and then automatically builds up full braking power. The anti-lock braking system (ABS) then meters the braking power up to the slip threshold, which is how steering control is maintained. Once the driver releases the brake pedal, the automatic brake boosting is immediately terminated.