New level of safety: Intelligent assistance systems with a keener eye

May 9, 2013
What started with the PRE-SAFE® system some ten years ago and continued with DISTRONIC PLUS has resulted in a new dimension of motoring at Mercedes-Benz, with comfort and safety merged into one: "Mercedes-Benz Intelligent Drive". The Coupé and Cabriolet are optionally available with a whole host of new assistance systems on board which help to make motoring more comfortable and safer. 
In the main markets, both models are fitted as standard with COLLISION PREVENTION ASSIST, a radar-based proximity and collision warning system with adaptive Brake Assist. This can significantly reduce the risk of a rear-end collision. Also forming part of the standard equipment is ATTENTION ASSIST, which is now able to warn of inattentiveness and drowsiness across a wider speed range and to inform the driver about their level of alertness and the amount of driving time which has elapsed since their last break. It also offers adjustable sensitivity levels. 
"The intelligent assistance systems of the future will be able to analyse complex situations and recognise potential dangers out on the road with the aid of improved vehicle sensing systems even more accurately than today," explains Prof. Dr Thomas Weber, Member of the Daimler Board of Management responsible for Group Research and Head of Mercedes-Benz Cars Development. "Figuratively speaking, the new E-Class Cabriolet and Coupé don't just have eyes at the front, they have 360-degree all-round vision."  
Of crucial importance in this respect is the networking of all systems, or "sensor fusion" as the safety experts call it. Mercedes-Benz is continually enhancing the performance capabilities of its assistance systems with the aim of ensuring comprehensive protection, not just for the occupants of a Mercedes-Benz, but for all other road users too. 
The new systems hold tremendous potential for either preventing accidents or mitigating their consequences according to Prof. Dr Weber: "Take, for instance, the new assistance system BAS PLUS with Cross-Traffic Assist. The results of our accident research based on the data from the GIDAS (German In-Depth Accident Study) indicate that it could mitigate or prevent 27 percent of all accidents at road junctions resulting in personal injury. That equates to some 20,000 accidents a year in Germany alone." 
New sensors, new senses, new intelligence  
The basis for the innovative functions comes courtesy of sensors and appropriately networked algorithms. 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 degrees and is capable of, amongst other things, spatial detection of objects and pedestrians moving crossways ahead, and of calculating their path. The camera's two "eyes" provide it with a three-dimensional view of the area up to approx. 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 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. The system of radar sensors comprises two short-range radar sensors in the front bumper with a range of 30 metres and a beam angle of 80 degrees, which are complemented by a long-range radar system (200 metres, 18 degrees) including medium-range detection (60 metres, 60 degrees). The data from the camera and radars is amalgamated in a common control unit in order to provide the system-specific data for the various functions. 
Assistance with lateral lane guidance: DISTRONIC PLUS with Steering Assist 
The DISTRONIC PLUS proximity control system is a driver aid designed to help keep a safe distance to a 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 Steering Assist, which helps drivers to stay centred in their lane by generating the appropriate steering torque when travelling on a straight road and even on gentle bends.  
The stereo camera recognises lane markings as well as vehicles driving ahead together with their spatial positioning. When driving at slow speeds, e.g. in congested traffic, Steering Assist can use the vehicle ahead as a means of orientation, enabling semi-autonomous following of traffic jams even when there are no clear lane markings visible. As a result, the system is able to further boost driving comfort and substantially ease the driver's workload in many traffic situations.  
The new Steering Assist sub-function integrated into the DISTRONIC PLUS system is predominantly based on the new stereo camera. At the same time, the area in front of the vehicle continues to be monitored by two short-range radar sensors and a long-range radar sensor with medium-range detection. The system fuses the data gleaned from both technologies, 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. Any speed between 30 and 200 km/h can be selected as the desired cruising speed, even when stationary. A green steering wheel symbol appears in the instrument cluster to indicate when the Steering Assist is operating while DISTRONIC PLUS is activated. Meanwhile, linear controlling actions (DISTRONIC PLUS function) continue to be visualised in the speed display by means of circular segments and the speedometer needle. 
Drivers must keep their hands on the steering wheel at all times in case the steering torque applied by the system is insufficient or, for example, is not applied at all because the lane cannot be detected. Legal considerations also mean there are no plans to introduce hands-free driving. The system's design is so refined that the sensors can detect whether the driver's hands are actually on the steering wheel. If they are not, a visual warning is output first. Should the driver fail to react to this, a warning signal sounds and lateral lane guidance is deactivated. This does not affect the cruise control function, however, which continues to be operative.  
Needless to say, the driver is able to override the Steering Assist function at any time. If the driver signals to change lane, for instance, the lateral guidance function will switch into passive mode for the duration of the lane change. 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 road is clear.  
By combining the radar and camera data, DISTRONIC PLUS is also able to detect both vehicles cutting in and vehicles ahead in adjacent lanes and take any necessary action promptly. This can prevent illegal overtaking on the inside lane on motorways and similar multi-lane highways, for example, by adapting the speed to that of vehicles in the outside lanes.  
Braking assistance for cross traffic: BAS PLUS with Cross-Traffic Assist  
Apart from material damage, accidents at junctions often result in serious injuries, too. The new Brake Assist BAS PLUS with Cross-Traffic Assist from Mercedes-Benz is therefore capable of more than just helping the driver to avoid collisions with vehicles ahead or lessening their consequences in a purely linear direction: the new Cross-Traffic Assist function can also come to the driver's aid when there is a risk of a collision 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 around 72 km/h, while BAS PLUS is able to aid the driver in linear situations at any speed. 
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).
With pedestrian detection and city brake function:  BAS PLUS and PRE-SAFE® Brake  
Pedestrian detection has been added to the BAS PLUS and PRE-SAFE® Brake functions, while autonomous braking for vehicles in front has undergone a major enhancement too. 
Thanks to the combination of stereo camera and radar sensors, it is now possible to detect pedestrians in front of the vehicle. Visual and acoustic warnings are triggered when a risk of a collision is spotted. If the driver then reacts by braking, the braking power will be boosted by BAS PLUS as the situation requires, right up to a full brake application. Should the driver fail to react, PRE-SAFE® Brake triggers autonomous vehicle braking. The PRE-SAFE® Brake with pedestrian detection is active up to approx. 72 km/h, and is able to prevent collisions with pedestrians autonomously up to an initial speed of 50 km/h.  
Evaluations of GIDAS accident data indicate that this new technology could avoid six percent of pedestrian accidents and reduce the severity of a further 41 percent. The operating range of the autonomous braking function for stationary vehicles has been optimised so that rear-end collisions can likewise be avoided at speeds of up to 50 km/h.  
BAS PLUS with Cross-Traffic Assist and the PRE-SAFE® Brake with pedestrian detection rely on the same sensors employed for the adaptive proximity control system DISTRONIC PLUS with Steering Assist: the new stereo camera plus the multistage radar sensor system.
Reacts to 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 a collision risk is detected because the adjacent lane is not clear and the vehicle crosses the lane markings, not only does the system cause the steering wheel to vibrate in pulses as a tactile warning for the driver, it also guides the vehicle back into lane by applying a corrective braking force on one side via the ESP®. It thereby forms the ideal complement to the Active Blind Spot Assist, and for the first time means that it is also possible to prevent the often serious collisions with oncoming traffic. 
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. 
Now also identifies no-overtaking zones and no-entry signs:  Traffic Sign Assist 
A new Traffic Sign Assist system 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 any additional information and the lifting of speed limits, even when the signs appear on overhead gantries or at 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. 
No-overtaking zones and the signs signalling their end are also registered and displayed. If the vehicle passes a sign imposing no-entry restrictions, an acoustic warning is additionally emitted together with a visual warning in the instrument cluster – effectively helping to prevent serious accidents caused by drivers unintentionally driving the wrong way down a road.
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 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.  
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 
Active Parking Assist 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.  
The Active Parking Assist 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.  
PRE-SAFE® PLUS: occupant protection for an impending collision from the rear  
Mercedes-Benz has extended the PRE-SAFE® anticipatory occupant protection system to cover dangerous situations caused by traffic following behind.  
A radar sensor in the rear bumper monitors the traffic behind the vehicle and can detect an impending rear-end collision. The system alerts the driver of the vehicle behind to the dangerous situation by causing the rear hazard lights to flash at high frequency (not for the USA and Canada). 
If the vehicle is stationary, PRE-SAFE® PLUS will keep it firmly braked, thus reducing any forward jolt. This can greatly reduce the strain placed on the occupants and the risk of whiplash injuries, for instance. Firmly applying the vehicle's brakes can help to prevent secondary accidents too, such as running into a vehicle in front, for example, or colliding with pedestrians or other road users at junctions. 
PRE-SAFE® PLUS additionally triggers the PRE-SAFE® anticipatory occupant protection measures, such as the reversible belt tensioners and active NECK‑PRO head restraints, just prior to impact.  
Permanent high beam with no dazzling: Adaptive Highbeam Assist Plus 
Around 20 percent of all road journeys in Germany are undertaken at night. But this is when some 40 percent of all accidents occur. A main cause here is poor visibility. According to a study by the University of Michigan, high-beam headlamps can only be used during eight percent of driving time – which is nowhere near enough. Based on this, it can be assumed that the time during which high-beam headlamps can be used in Germany is likely to be even lower, given the denser amounts of road traffic compared with the USA. 
For the first time, Adaptive Highbeam Assist Plus allows the high-beam headlamps to be kept on permanently while driving by masking out any other road user detected in the beams' cone of light. If the camera-based system registers either oncoming traffic or vehicles ahead, it will adapt the light distribution according to the specific situation when the high beam is switched on. Consequently, the driver can simply leave the high-beam headlamps on at all times and use their full range without irritating or even endangering other road users. There is no need to switch them on and off manually, resulting in a significant increase in the overall driving time with high beam. 
Adaptive Highbeam Assist Plus likewise makes use of the new stereo camera also employed by other assistance systems. If its image recognition algorithm picks up a vehicle that is oncoming or driving ahead, it actuates a mechanism in the headlamp module. This then masks the portion of the LED headlamps' main-beam cone of light where there are other vehicles, to prevent their drivers being dazzled. If road users are detected outside the area that can be masked – for instance when cornering with multiple vehicles in the headlamps' beams – the system will switch to the familiar function of situation-based headlamp range control using the low-beam headlamps. 
Possible backglare caused by increased use of the high beam and highly reflective signs at the side of the road is also detected and eliminated by dimming the relevant portion of the headlamps.
Adaptive Highbeam Assist Plus builds on the Adaptive Highbeam Assist system first introduced by Mercedes-Benz in 2009. If this system detects oncoming traffic or traffic driving ahead with the help of a camera, it dips the headlamps and automatically adapts the low beam's range according to the situation. In this way, it allows the road to be illuminated for a long way ahead without dazzling other drivers. In addition to this, adaptive control of the low-beam headlamp range with smooth transitions results in gentler lighting changes that the eyes can quickly adjust to.  
At a glance 
The main new functions of Mercedes-Benz assistance systems
Comfort-oriented assistance
helps with keeping the vehicle in its lane
Steering Assist
able to follow traffic in traffic jams
Safety - longitudinal guidance
can also detect crossing traffic and boost
the braking power applied by the driver can
detect pedestrians and boost the braking
power applied by the driver
can detect pedestrians, avoid collisions
with pedestrians or stationary traffic at initial
speeds up to 50 km/h by means of
autonomous braking, and reduce the collision severity at speeds up to 72 km/h
Safety - towards the rear
can detect impending collisions from the
rear alerts by activating hazard warning lights at high frequency firmly applies the
stationary vehicle's brakes in a rear-end collision to reduce the strain on the
occupants and prevent secondary accidents triggers PRE-SAFE® occupant
protection measures just prior to impact
Safety - lateral guidance
Active Lane Keeping Assist
can detect oncoming traffic and whether the
adjacent lane is occupied, and prevent the
vehicle from leaving its lane unintentionally by applying the brakes on one side
Safety - at night
Adaptive Highbeam-
allows high-beam headlamps to be kept on
Assist Plus
permanently without dazzling traffic by
masking out other vehicles in the beams' cone  of light
Safety - when parking
Active Parking Assist
enables automated parking in both parallel
and end-on spaces with automatic steering
and brake control enables automatic
manoeuvring out of parallel parking spaces
Driver's level of attention and condition
can warn of in attentiveness and
drowsiness in an extended speed range of 60 to 200 km/h can provide the driver with
information on his level of fatigue and the amount of driving time which has elapsed since the last breakprovides an adjustable
sensitivity level