The new Mercedes-Benz S-Class: The driving assistance systems - Helpers in the background

Avoid accidents and mitigate their consequences - this is the integrated approach adopted by Mercedes-Benz Accident Research under the heading "Real Life Safety". Mercedes-Benz is systematically pursuing this strategy with numerous new assistance systems and greatly enhanced functions. Comfort and safety are enhanced at the same time, and new possibilities are opened up for motorists and car developers. Mercedes-Benz calls this "Intelligent Drive". The new functions all rely on the same sensor system, comprising a new stereo camera together with multistage radar sensors.

The support functions range from relieving the burden on the driver and therefore increasing comfort, to issuing visual, acoustic and/or tactile warning signals, to boosting the driver's reactions. Some systems are even able to take corrective action in an emergency, such as autonomous applications of the brakes to prevent an accident or lessen its severity. Here is a summary of the new assistance systems and those with notably enhanced functionality:

- DISTRONIC PLUS with Steering Assist and Stop&Go Pilot takes the burden off the driver when it comes to lane guidance and is also able to follow vehicles in traffic jams automatically.

- For the first time, thanks to the stereo camera the Brake Assist system BAS PLUS with Cross-Traffic Assist is able to detect crossing traffic and pedestrians too, and to boost the braking power applied by the driver accordingly.

- If the lane markings are broken lines, Active Lane Keeping Assist can detect when the adjacent lane is occupied, especially by oncoming traffic, and reduce the risk of the vehicle leaving its lane unintentionally by applying the brakes on one side.

- Adaptive Highbeam Assist Plus allows the high-beam headlamps to be kept on permanently without dazzling traffic by masking out other vehicles in the beams' cone of light.

- Night View Assist Plus was further developed and supplemented by a thermal imaging camera. Night View Assist Plus can alert the driver to the potential danger posed by pedestrians or animals in unlit areas in front of the vehicle by automatically switching from the speedometer to a crystal-sharp night view image and highlighting the sources of danger. A spotlight function is furthermore able to flash any pedestrians detected ahead.

- ATTENTION ASSIST can warn of inattentiveness and drowsiness in an extended speed range and notify the driver of their current state of fatigue and the driving time since the last break, offers an adjustable sensitivity setting and, if a warning is emitted, indicates nearby service areas in the COMAND navigation system.

Sensors: intelligent networking of eyes and ears

Mercedes-Benz is making a major leap forward with the introduction of the Stereo Multi-Purpose Camera (SMPC), or stereo camera for short. Just like the Multi-Purpose Camera (MPC) fitted previously, it is positioned behind the windscreen in the vicinity of the rear-view mirror. It has an aperture angle of 45° and is capable of detecting the position and movement of objects, especially vehicles and pedestrians, in three dimensions in each case. The "6D-Vision" technology nominated last year for the German Research Prize is used for this purpose for the first time. The camera's two "eyes" provide it with a three-dimensional view of the area up to around 50 metres in front of the vehicle, and it is able to monitor the overall situation ahead for a range of up to 500 metres. In this way, the new camera is able to provide data for processing by various systems.

Intelligent algorithms evaluate this information in order to detect and carry out spatial classification of vehicles that are driving ahead, oncoming or crossing, as well as pedestrians and a variety of traffic signs and road markings within a large field of vision.

Whereas the stereo camera's lenses act as the car's eyes, the radar sensors are its ears, so to speak, and provide additional data about the distance from objects. The system of radar sensors comprises two short-range radar sensors in the front bumper and in the side of the rear bumper with a range of 30 m and a beam angle of 80°, which are complemented by a long-range radar (200 m, 18°) including medium-range detection (60 m, 60°). In addition, the multi-mode radar (80 m, 16° and 30 m, 80°) fitted at the front of the standard vehicle with COLLISION PREVENTION ASSIST is installed in the middle of the rear bumper. The data from the camera and radars is amalgamated in a control unit in order to provide the system-specific data for the various functions.

Comfort-enhancing assistance with lateral lane guidance: DISTRONIC PLUS with Steering Assist and Stop&Go Pilot

The DISTRONIC PLUS adaptive cruise control is a driver aid designed to keep the vehicle at the desired distance from another vehicle in front that is travelling slower than the selected cruising speed. This basic radar-based function has now been enhanced by the addition of a Steering Assist with Stop&Go Pilot, which helps drivers to stay centred in their lane by generating the appropriate steering torque when travelling on a straight road and even in gentle bends.

The stereo camera recognises lane markings as well as vehicles driving ahead together with their spatial positioning, and relays this information to the electric steering assistance system. By generating the appropriate steering torque, the system can enhance ride comfort in the speed range up to 200 km/h and greatly assist the driver in many traffic situations. At speeds up to 60 km/h, the Stop&Go Pilot 'intelligently' decides whether to use the vehicle in front or the road markings as a means or orientation, enabling semi-autonomous following of traffic jams even when there are no clear lane markings visible. The system fuses the data gleaned from the stereo camera and the radar sensors, calculates any reactions required, and then regulates the vehicle's linear speed as requirements dictate by controlling engine power, transmission and brakes, as well as actuating the electric steering for lateral vehicle guidance.

DISTRONIC PLUS with Steering Assist can be activated as before with a selector lever on the steering wheel in a speed range from 0-200 km/h, now also with the vehicle standing still and no vehicle moving ahead of it. Any speed between 30 km/h and 200 km/h can be selected as the desired cruising speed. The driver starts off in this case by pulling the DISTRONIC PLUS lever or tapping the accelerator.

A green steering wheel symbol appears in the instrument cluster to indicate when the Stop&Go Pilot is operating while DISTRONIC PLUS is activated. Meanwhile, linear controlling actions (cruise control function) continue to be visualised in the speed display by means of circular segments and the speedometer needle.

The system's design is so refined that the sensors can detect whether the driver's hands are actually on the steering wheel. If the system recognises that the driver has taken their hands off the steering wheel while the car is moving, depending on the situation, the detected surroundings and the speed, a visual warning is issued in the instrument cluster first; then a warning signal sounds and the Steering Assist is deactivated. This is additionally indicated by changing the steering wheel symbol from green to white. The linear control action remains unaffected by this and continues to be available. That means the system has an intelligent hands-off detection feature that brings the driver's hands back to the wheel when necessary. The use of DISTRONIC PLUS requires no change in driver behaviour – those who previously drove hands-free in a tailback can continue to do so (much more safely). Thus, Mercedes-Benz offers relaxed driving mainly over long distances and on motorways, especially during otherwise tiring and annoying (slow) tailback tracking.

The performance capabilities of the basic DISTRONIC PLUS function have been increased once again. Now, the system is able to brake at a rate of up to 5 m/s² without any intervention from the driver. If the "S" drive mode button is pressed, the rate of acceleration increases, too. Vehicle acceleration is also far more dynamic if the driver signals a wish to overtake by switching on the indicators, assuming the adjacent lane is clear.

By combining the radar and camera data, DISTRONIC PLUS is now also able to detect both vehicles cutting in and vehicles ahead, and vehicles ahead of them, in one's own lane and in adjacent lanes, and take any necessary action promptly. This can prevent, for example, illegal overtaking on the inside lane on motorways and similar multi-lane highways by adapting the speed to that of vehicles in the outside lanes (at speeds above 85 km/h), especially when a tailback begins to dissolve and in streams of traffic. At lower speeds, permissible overtaking on the inside lane with a maximum speed differential of 20 km/h is possible.

It goes without saying that the driver always can override DISTRONIC PLUS with Steering Assist. For instance if they signal with their indicators that they wish to change lanes, the lateral assistance remains passive as long as it takes to change lanes.

Braking assistance for cross traffic too: BAS PLUS with Cross-Traffic Assist

City centre junctions are a major accident blackspot. The collisions here can mostly be put down to driver distraction or misjudgement. Whereas humans often react too slowly, assistance systems are immune to that brief moment of shock.

Apart from material damage, accidents at junctions often result in serious personal injuries, too. The new Brake Assist BAS PLUS from Mercedes-Benz is therefore capable of more than just helping the driver to avoid collisions with vehicles ahead or lessen their consequences in a purely linear direction: the new Cross-Traffic Assist function can also come to the driver's aid in critical situations with cross traffic at junctions.

If this anticipatory system detects a hazardous situation of this type, it prompts the driver to start emergency braking by activating visual and acoustic warnings. If the driver presses the brake pedal too tentatively, BAS PLUS will step in by automatically boosting brake pressure for effective emergency braking, even applying the brakes at full power if necessary. Applying just the right amount of braking power for the situation at hand maximises the available braking distance for traffic behind.

The Cross-Traffic Assist function is operative at speeds up to approx. 72 km/h, while BAS PLUS is able to aid the driver in linear situations at any speed.

Brake Assist BAS PLUS with Cross-Traffic Assist is potentially able to either prevent or lessen the severity of around 27 percent of all accidents at road junctions resulting in injury. This equates to some 20,000 accidents a year in Germany alone (source: investigations carried out by the GIDAS – German In‑Depth Accident Study – and Mercedes-Benz Accident Research).

Detects broken lines too: Active Lane Keeping Assist

The new improved version of Active Lane Keeping Assist is now also able to intervene should the driver inadvertently cross a broken line when the neighbouring lane is not clear, meaning that a lane change could result in the risk of a collision. The system can determine if this is the case using the information from the stereo camera and the radar system. The latter has been supplemented by a sensor at the rear, which works in unison with the other sensors in the front and rear bumpers.

Active Lane Keeping Assist is not only capable of recognising critical situations such as overtaking vehicles, vehicles to be overtaken and parallel traffic, it can also respond effectively to oncoming traffic. If the system detects the vehicle crossing the lane markings when the adjacent lane is not clear, not only does it cause the steering wheel to vibrate in pulses as a tactile warning for the driver, it guides the vehicle back into lane by applying a corrective braking force on one side via the ESP®, now also when the vehicles crosses broken lines. It thereby complements the Active Blind Spot Assist, and for the first time also enables the often fatal collisions with oncoming traffic to be avoided.

Active Lane Keeping Assist is active at speeds between 60 and 200 km/h. If driver activity in the form of active steering, braking or acceleration is detected, for example, or when the indicators are switched on, both the warning and the corrective brake actuation are suppressed. Using the instrument cluster the system can be set for two levels – Standard or Adaptive.

Now recognises no-overtaking zones and access restrictions, too: Traffic Sign Assist with wrong-way driver warning function

A new Traffic Sign Assist which builds on the capabilities of the previous Speed Limit Assist represents yet another contribution to accident prevention from Mercedes-Benz. The system is now also able to recognise no-overtaking zones and alert drivers to no-entry restrictions.

The camera on the inside of the windscreen continues to pick up speed limit signs, including those on overhead gantries and in roadworks, for example. The camera's data is cross-referenced against the information in the navigation system and can be displayed in both the instrument cluster and the map view. If the camera fails to spot any road signs showing a speed limit or a speed limit is lifted, the legal speed limits based on the navigation data are shown instead, such as a maximum speed of 100 km/h on country roads in Germany or 50 km/h in built-up areas. Supplemental signs are also recognised and displayed according to situation (e.g. "in the wet").

No-overtaking zones and the signs signalling their end are also registered and displayed, while in the case of signs imposing access restrictions, through the wrong-way driver warning function an acoustic warning is emitted together with a visual warning in the instrument cluster – making an effective contribution towards helping to prevent serious accidents caused by wrong-way drivers.

Visualising drowsiness: ATTENTION ASSIST

A quarter of all motorway accidents in Germany are put down to drowsiness, making it one of the most frequent causes of accidents, most of which are of a serious nature. In 2009, Mercedes-Benz presented ATTENTION ASSIST, which is able to detect telltale signs of inattentiveness and increasing drowsiness based on changes in steering behaviour and a host of other factors.

The system has been subject to ongoing development, and the latest version has the ability to detect drowsiness and inattentiveness across a far greater speed range from 60 - 200 km/h. Furthermore, the system's sensitivity can be adjusted, e.g. for drivers who already feel tired when they get behind the wheel.

A new menu in the instrument cluster display also makes the system more tangible and transparent for the driver by visualising the current ATTENTION ASSIST level and the driving time since the last break. What's more, it is also possible to see whether the system is active in the current driving situation. If the usual ATTENTION ASSIST warning recommending the driver to take a break is emitted, nearby service areas can be indicated in the navigation system.

The system can be deactivated by making the appropriate selection in the instrument cluster menu. However, it will always be automatically reactivated with the sensitivity setting last selected the next time the vehicle is started.

Automatic manoeuvring into and out of parallel and end-on parking spaces: Active Parking Assist with PARKTRONIC

Active Parking Assist with PARKTRONIC enables automated parking with active steering and brake control in both parallel and end-on spaces. It is an advanced version of the PARKTRONIC system with Parking Guidance offered previously. What's more, the system is now also able to manoeuvre out of parallel parking spaces again all by itself with automatic steering and brake control, assuming the vehicle was parked there automatically previously.

When travelling at speeds below 30 km/h, ultrasonic sensors with an extended range in the bumpers' side sections survey the nearside of the road for suitable parallel and end-on parking spaces. The same procedure is carried out for the far side of the road if the driver indicates accordingly. A symbol in the instrument cluster shows that the system is in the process of measuring. If a suitable parking spot is identified, an arrow appears alongside the symbol indicating that the system is ready for automatic parking. All the driver now has to do to activate the system is engage reverse gear and confirm by pressing the OK button on the steering wheel.

Active Parking Assist with PARKTRONIC steers and brakes the vehicle automatically as well as indicating the required driver actions in the display each time, such as the gear to be selected. The driver moves the vehicle by lightly pressing the accelerator or releasing the brake.