Driver assistance systems - an overview
This is where you can find useful information on driver assistance systems - in glossary format.
Important safety note
Although driver assistance systems are available in the most diverse forms and functional depths, they all have two things in common: They make driving a car safer and more comfortable. Modern sensors such as ultrasound and laser sensors (Lidar sensors) and, of course, surround-view cameras ensure safe distance recognition and also recognition of the driving environment. A (central) control unit processes the data and converts it into signals such as warning beeps, visual messages or even active reactions like braking intervention or acceleration impulses (speeding up). Today these actions usually occur digitally and within a fraction of a second.
The more extensively a driver assistance system engages in the actual driving operation, the more it begins to "virtually" replace the driver (the cue for driverless driving). Even if this only happens consciously in dangerous situations, the question of liability is still being raised. This is where manufacturers are bound by duty to minimize risks and prevent hazards of all kinds. An ethics commission has now embraced this subject and initial framework conditions have already been defined. But the dilemma of this issue still remains controversial. Driving assistance systems can, however, as a rule be switched off by drivers.
Because of the variety of systems available and all the individual solutions offered by different manufacturers, it is impossible to make a general statement as to which sensor system and which sensor generation would be suitable for use in any one particular application. Vehicle manufacturers use the most diverse driver assistance systems, practical combinations and new technologies in all the different vehicle classes. Designations are not always identical and, to a certain extent, manufacturers use their own terminology and abbreviations. It is not possible here to examine all technical details and every single manufacturer.
The calibration of sensors and indeed of cameras is somewhat tricky and this should definitely be carried out by vehicle experts in the workshop. Such tasks demand the relevant diagnostic equipment, the suitable software and also optical calibration apparatus (e.g. the equipment from Hella Gutmann Solutions).
The following overview, appearing in alphabetical order, lists the most common driver assistance systems including short descriptions for each one.
Das Antiblockiersysteme (ABS) gehört zu den ersten Fahrerassistenzsystemen überhaupt. Als erstes Serienfahrzeug verfügte 1978 die Mercedes S-Klasse über ein Antiblockiersystem (ABS 2 von Bosch). Es folgte der BMW 7er. Das ABS verhindert beim Bremsvorgang ein Blockieren der Räder und sorgt so dafür, dass das Fahrzeug noch beherrschbar bleibt. Zusätzlich können deutlich kürzere Bremswege erreicht werden, das Fahrzeug kommt nicht ins Schleudern und bricht nicht aus.
Einzelne Drehzahlsensoren am Rad (Induktions- oder heute Hallgeber) messen über einen Loch- oder Zahnscheibe entsprechende Drehzahlunterschiede. Sinkt die Raddrehzahl gegenüber den anderen Rädern unverhältnismäßig wird der Bremsdruck am jeweiligen Rad minimiert, jedoch kurz danach wieder aufgebaut (Bremsdruckmodulation). Die Druckerhöhung nimmt der Fahrer als Pedalvibrieren wahr. Dabei öffnen und schließen in rascher Abfolge Magnetventile. Dies geschieht in der zentralen ABS-Regeleinheit. Sie verwertet permanent die Signale der Raddrehzahlsensoren und besteht aus dem Hydraulikblock inklusive Ventile, einer elektrischen Pumpe sowie dem Niedruckreservoir und dem elektronischen Steuergerät.
Aktuelle ABS-Versionen übernehmen noch weitere Funktionen, wie die intelligente Bremskraftverteilung über alle vier Räder. So sind je nach Fahrsituation und ohne aktiven Bremsvorgang weitere Regeleingriffe möglich um das Fahrzeug stabil auf der Straße zu halten (siehe auch ESP).
With adaptive steering or also with active steering (AFS - Active Front Steering), the steering ratio is performed variably. This means that steering behaviour varies in accordance with the actual driving situation and with the speed traveling. In this way the steering assistant enables easier manoeuvring at low speeds or when a vehicle is being parked. When vehicles are driving on the motorway or at higher speeds, adaptive steering brings about improved directional stability. An actuator inside the steering wheel (Ford) ensures the appropriate conversion of the steering impulses. A different model (BMW, Servotronic) varies the hydraulic steering support and - depending on the speed - in this way can make the steering smoother or harder or more direct.
The adaptive steering or active steering does not generate the necessity for any active steering intervention as is the case, for example, with lane-keeping systems.
Distance and speed regulating or also the automatic distance control (ACC=Adaptive Cruise Control) autonomously brakes and accelerates the vehicle depending on the flow of traffic. The vehicle "eases back" and brakes - e.g. when in bumper-to-bumper traffic - whenever necessary. Even a cutting in or merging of vehicles up ahead is recognised. The risk of pile-ups with rear end collisions is thus minimised and the driver is spared the constant stopping and starting action. This takes place within defined limits, e.g. up to a maximum speed and by observing a predefined safe distance. Such a process involves radar sensors monitoring the area next to and in front of the vehicle. The sensors measure the distance to the vehicle in front and accordingly trigger braking intervention or acceleration. These systems, in some instances, can apply the brakes to a vehicle completely – e.g. in traffic jams (ACC Stop & Go) - but without initiating an emergency brake procedure. In some systems, an alarm tone also signals and gives warning of a hazardous situation.
ACC is also frequently combined with steering control systems or with lane tracking assistants such as Lane Assist.
With the adaptive high beam, i.e. the adaptive high beam assistant, the principle of a sliding headlamp leveling system applies. The xenon headlamps are coupled with a camera capable of providing intelligent image evaluation. Depending on the camera signal given (from oncoming traffic or from preceding vehicles), the system changes the illumination range, which can reach either up to 300 m or just to the anti-glare zone of the next vehicle. As soon as the camera no longer recognises any other road users, the system once again slowly and in a sliding motion switches to 'high beam'.
Straightforward high-beam assistants with H7 lamps simply switch the high beam light on and off using a light sensor (camera sensor). The system also reacts to ambient lighting and partly to reflective road signs (See also light source recognition).
The so-called laser light, currently being used by BMW and Audi, also reacts in a fully adaptive way. And as this involves no movement of mechanical elements, the reaction speed is high. Adjustments for high beam, low beam and bend lighting are electronically controlled to suit individual requirements.
Adaptive chassis will adapt by almost anticipating possible road unevenness or dangerous bends. State-of-the-art systems are connected to a camera, among other things, which can identify the road situation. Passive systems are also common. These can be activated at the touch of a button inside the vehicle (comfort, standard, sport).
The chassis is then changed by means of electrically controlled valves in the shock absorbers. This means that either more or less oil flows into each shock absorber. A (temporary) transformation of the damper characteristics is the result.
The objective of an adaptive chassis is to improve driving characteristics by taking into account braking, steering and acceleration processes. This aims to increase safety for passengers and ramp up vehicle performance.
The task of adaptive bend lighting is to illuminate the streets and the sidewalk when vehicles turn off and drive around bends. A steering-angle sensor measures the angle of the steering wheel and transmits the signal to stepper motors which then accordingly adjust the headlamp elements.
A simple and mechanically less complex variant switches on an auxiliary lamp in order to illuminate the surrounding area when a certain steering angle is achieved.
Bend lighting can be achieved more effectively with LED, matrix, laser or LCD headlamps. No mechanical system is required for this - the appropriate light sources are simply steered. These systems are performed in a highly intelligent way. See also fully adaptive light distribution.
The manoeuvring and parking of a passenger car trailer is not everyone's idea of fun. So Volkswagen, for example, with its 'Trailer Assist' offers drivers a parking or 'manoeuvring/steering' aid. With the system activated and the vehicle combination in the correct position, the car and trailer steer in reverse into the parking space. Applying the brakes and stepping on the accelerator remain the responsibility of the driver. With the help of the outside mirror adjustment knobs, the driver can fix the desired direction of travel for the trailer.
The so-called Trailer Backup Assist takes things a step further. Drivers can park their car/trailer vehicle combination from outside by using a smartphone - as if by remote control. During this operation Trailer Backup Assist makes use of the functions of the electric power steering, of the ESP electronic stability program, of the electronic accelerator pedal and also of the trailer coupling with its articulation angle sensor. The steering angle of the trailer and the speed of the car/trailer vehicle combination can be defined by using an app - and thus the car-trailer can be successfully parked.
The anti-lock braking system (ABS) is one of the first ever driver assistance systems. As the first series vehicle, the Mercedes S-Class boasted an anti-lock braking system in 1978 (ABS 2 from Bosch). The BMW 7 series then followed suit. During braking the ABS prevents the wheels from blocking and thus ensures that the vehicle can still be kept under control. Furthermore, considerably shorter braking distances can be achieved and the vehicle neither skids nor swerves.
Individual RPM sensors on the wheel (inductive or more commonly today Hall generators) measure the relevant rpm differences across a perforated disk or a toothed disk. If the wheel speed drops disproportionately with respect to the other wheels, the brake pressure on each wheel is reduced but is re-established shortly afterwards (brake pressure modulation). The driver becomes aware of the pressure increase by means of pedal vibration. At the same time solenoid valves open and close in quick succession. This takes place in the central ABS control unit. It permanently utilises the signals received from the wheel speed sensors. It is made up out of the hydraulic block including the valves, an electric pump and also the low pressure reservoir and the electronic control unit.
Current ABS versions take over even more functions such as intelligent brakeforce distribution over all four wheels. In this way, depending on the driving situation and without the brakes being actively applied, other regulating intervention is possible with a view to keeping the vehicle stable on the road (See also ESP).
Park Out Assist for exiting a parking space (e.g. from Volkswagen) or the Rear Cross-Traffic Alert (RCTA, e.g. from Mazda) both use the radar sensors of the blind spot warning (Blind Spot Detection, BSD). When the car is pulling out of its parking space, the sensors recognise vehicles or pedestrians crossing from behind or indeed any other kinds of obstacles before the driver becomes aware of them. Warning is given in the form of an acoustic signal or via flashing LEDs (e.g. in the rear-view mirror). The angle of detection is usually 120 degrees.
If the driver assistance system recognises an imminent collision, it alerts the driver by means of a warning beep and/or a visual warning (e.g. using LEDs in the rear-view mirror). With some systems, automatic braking of the vehicle is also carried out (See also Park Assist and Garage Assist).
Park Out Assist for exiting a parking space is activated when the reverse gear is engaged or when the automatic gear transmission is set on 'R'. If the vehicle is fitted with a hitch or coupling device and a trailer is being towed, then the Park Out Assist for exiting a space is deactivated.
The Safe Exit Assist warns against the dangers of opening vehicle doors when traffic is approaching from behind. Radar sensors, which provide signals including those for Park In Assist, Lane Change Assist, Rear End Pre-Crash Assist or for Blind Spot Detection, recognise vehicles, cyclists or individual pedestrians as potential obstacles. Depending on the type of vehicle, either an audible warning is given or the hazard is visually indicated by means of a light signal in the field of view or in the door trim panel.
As an example, the HELLA 24 GHz radar sensors allow vehicle manufacturers to offer their customers systems such as the Safe Exit Assist in all automotive segments. The 24 GHz narrowband technology has almost worldwide homologation, thus making it very suitable for global platforms.
When an accident happens, crash sensors (which are also responsible for the opening of airbags) or collision sensors report and forward data to a central unit. Depending on the ACN system (Automatic Crash Notification), information such as the location, the severity of the accident and all relevant additional data is forwarded to the emergency centre. This emergency centre also endeavours to make contact with the driver. Necessary measures such as the making of emergency calls are then taken. These systems are also described as eCall and from April 2018 are compulsory for new vehicles. Their names are manufacturer-specific with examples such as OnStar (GM), BMW Assist, Safety Connect (Toyota) and Car-Net (Volkswagen).
As well as having a variety of connectivity functions, some of the systems also boast their own alarm systems, which monitor the doors and the ignition lock and also the functioning of an inclination and vibration sensor. In the case of Volkswagen, for example, any form of manipulation carried out on the vehicle, together with all details on the vehicle's position, is sent via text message to a central office.
Because the systems are also capable of transferring other data including vehicle and location-specific information or, if necessary, they can also create a driving profile, critical discussions revolving around the subject of data protection remain very much an issue. Independent workshops not bound to a certain manufacturer consider themselves to be at a disadvantage since vehicle-specific data (mileage, service levels, wear and tear information) (can) be sent to the manufacturer or to the nearest brand dealers.
There are also simple, retrofitable accident reporting systems on the market, tools which use an app to give information on any incidents or accidents.
Everyone knows the sometimes very tight, narrow lanes in the vicinity of roadworks on the motorway or side roads. Enter Construction Zone Assist which, with cameras (stereo cameras) and ultrasonic sensors, makes sure that the driver stays in the lane even when it is exceptionally narrow so that no collision with other road users can be caused. If required, the appropriate steering corrections are performed while, at the same time, it is ensured that a safe distance to the vehicle in front and to both sides is observed. Furthermore, some Construction Zone assistants give audible and visual warnings in good time if narrow stretches are expected.
These systems, however, are limited in their effectiveness. In thick fog or when the sun is low, such driver assistance systems switch off.
Hill Hold Assist prevents the vehicle from rolling back when starting up on a mountain road thanks to braking intervention applied on the rear axle. The brake (EPB= Electrical Parking Brake) is released as soon as clutch engagement completes the start. Vehicles with automatic or dual clutch transmission require the switch position to be set on 'D'. In wintry conditions the Traction Control System provides the necessary grip for countless numbers of vehicles (See also Traction Control System - TCS).
The glare-free high beam, also called the vertical cut-off line or Dynamic Light Assist, follows the principle of a constantly switched-on high beam that in no way dazzles other road users. The (earlier) xenon-based system automatically tailors light distribution to suit the traffic situation by using a small rotating drum and masking.
Today the glare-free high beam is created by means of LED headlamps. The principle, however, remains the same. Individual LEDs are selected and switched on and off. Examples of this are the Audi Matrix LED light and the Mercedes-Benz Multibeam LED light. An intelligent camera positioned behind the vehicle windshield is instrumental in the functioning of the control system. It recognises headlamps or rear lights of vehicles in front and takes over other tasks of surveillance (object detection).
With both these systems, the disturbing and dazzling effect of lights on other road users is masked out. But the side of the road and all other parts of the road remain illuminated. The result is that pedestrians or animals such as deer can be recognised more clearly and sooner without passengers in oncoming traffic or in vehicles up ahead being dazzled.
Attention!! The prerequisite of an optimally functioning headlamp system is the correct adjustment. This should always be carried out by a professional technician in a workshop. Tips on this can be obtained from the following information. Hella Gutmann Solutions, for example, supplies the appropriate test and adjustment equipment.
The first brake assistance system was launched around 30 years ago with ABS. Its purpose is to prevent the wheels from blocking during braking. Since November 24, 2009, a basic brake assistant has been compulsory for new vehicles throughout the EU. During a jerky emergency stop, the system increases brake pressure via the ABS and in doing so supports a prompt deceleration of the vehicle, sometimes even to the point of it coming to a standstill (DBC = Dynamic Brake Control). Forward-looking sensors do not play a role in this process.
Emergency Brake Assist (EBA) monitors the area ahead of the vehicle by means of radar sensors or cameras. Should a pile-up or any collision with another road user or with an animal be imminent, then a warning is given to the driver. Brake pressure is also built up via ABS. Depending on the system, the vehicle triggers a deceleration and shortens the braking distance. If a collision is unavoidable, an emergency stop can also be initiated within the system limits. One such example is the Collision Prevention Assist Plus (CPAP) from Mercedes.
Other emergency brake assistants go by names such as Intelligent Brake Assistant (IBA, Infinity), Pre-Collision Safety System (PCS, Toyota) or quite simply Automatic Emergency Brake (AEB).
Systems for town traffic like the City emergency brake function from Volkswagen, City Safety from Volvo or Active City Brake (PSA Group) lessen the impact during rear-end collisions in inner city bumper-to-bumper driving or, in the best case scenario, they prevent them completely. The front sensors of the systems also recognise pedestrians, cyclists and animals. Depending on the system definition, each of these brake assistants function up to a certain speed, for example up to 20mph. A visual, haptic or acoustic warning (Forward Collision Warning) precedes the active brake intervention.
This term has absolutely nothing to do with a clean windshield. The brake disc wiper, as a result of light pressure being applied to the brake pads, ensures that the brake discs produce a "gentle" dry braking during heavy rain. The result is that braking response and performance are optimised. In order to initiate this procedure, the rain sensor sends the necessary signal to the ABS control unit.
So-called car-to-car communication models are being developed. This is where road users or vehicles communicate directly with one another via a self-sufficient system (no mobile phone network) and exchange traffic information even before their vehicles are within reach of one another. The individual drivers concerned - or their assistance systems on board - can then quickly prepare for a potentially dangerous situation such as a traffic jam even before they see the hazard.One example application is the electronic stop light.
The Dynamic Steering Response DSR and Dynamic Steering Traction Control make up a system which provides steering recommendations depending on the driving situation (e.g. if a vehicle oversteers in a bend). This manifests itself in a slight electromotive counter-steering, which stabilises the vehicle and improves its directional stability. During this process the DSTC operates together with the ESP and receives information via the four wheel speed sensors. It is hardly noticeable that the DSTC intervenes in the steering movements. Independent steering of the vehicle is no longer possible. The first to put this technology into serial production was Seat with the Cupra R.
With the help of car-to-car communication, (in future) it will be possible to use information from several vehicles in order to make driving safer. One example of how this can work is the electronic stop light. It supplies information about a braking manoeuver carried out by vehicles traveling ahead, vehicles which are not yet even in the field of vision. In the worst case it could be an emergency brake situation. This means that the driver who is following can, in a way, 'see ahead' what sort of potential danger is waiting for him - e.g. on narrow winding country roads - and then prepare himself accordingly. Another example is the Construction Zone Assist which can convey similar information about vehicles traveling ahead that are not in view (See also Car-to-Car Communication).
Together with the ABS (1979), the ESP is regarded as 'the classic' of the driver assistance systems. By way of brake intervention (and also intervention in engine management), it improves both directional stability and the stability of the vehicle in borderline situations (e.g. during understeering or oversteering). The ESP is seen as an extension of the ABS and the TCS (Traction Control System).
The term ESP is protected for use by Daimler. The first serial use of the Bosch system was seen in a Mercedes-Benz S Class in 1995. For this reason other manufacturers have chosen to use different designations such as DSC (Dynamic Stability Control, Jaguar and Mazda), VSA (Vehicle Stability Assist, Honda), VSC (Vehicle Stability Control, Toyota) or PSM (Porsche Stability Management).
ESP forms, for example, a basis which can be linked to other systems such as the electronic differential lock, the engine drag torque control, the hydraulic brake assistant including augmented braking power, trailer stabilisation and also the so-called brake disc wiper.
Automatic vehicle recognition comes into its own during heavy traffic in inner cities and also on multi-lane roads. In such situations vehicles in front often brake unexpectedly or change lanes abruptly. Whenever these scenarios arise, brake assistants, thanks to information provided by a vehicle recognition system, can immediately trigger the necessary measures (a visual and acoustic warning or an immediate brake intervention, or even an emergency stop).
Monitoring of the driving environment, performed for instance by an intelligent camera system from the Hella subsidiary of Aglaia, is in permanent operation. The system collects data on the position, direction and speed of other vehicles and then processes these details. Various types of vehicles like cars, trucks, buses, motor bikes or even scooters are recognised and classified. Their identification is not hampered by features such as the make, model or other any variations in appearance. This vehicle recognition continues to function even if adverse weather conditions prevail. Moreover, concealed vehicles can also be detected.
Pedestrian recognition is part of Brake/Emergency Brake Assist or, in other words, belongs to the environment monitoring system that implements both ultrasound and radar sensors and also cameras. Within the individual system limits and with each relevant algorithm, the system recognises when pedestrians suddenly step onto the road. Most pedestrian recognition systems, in such a situation, give an immediate warning - a visual and acoustic signal and, if necessary, they also trigger slight brake intervention. If the driver does not initiate a braking action, a possible emergency stop will be prepared. If the driver shows no reaction to the warnings given, the system, in the case of Volkswagen for example, automatically carries out an emergency stop within the defined limits.
Modern camera systems recognise road signs indicating speed limits. With the aid of intelligent, image-processing software, the vehicle is able to warn about these speed restrictions in real time. The warning can be an audible alert and/or it can be visual. Some systems even recognise road signs in foreign countries or they can change/delete the warning in towns or when speed limits have been lifted.
Even recognition of other traffic signs is possible as is the linking up with more assistance systems.
Navigation systems similarly indicate any form of speed restriction but with a certain condition, i.e. their software/map data must be up to date!
Rear End Pre-Crash Assist tracks vehicles approaching from behind and, in the event of an imminent collision, pre-activates safety devices such as airbags, seat belt tensioners or the automatic voltage shutdown of a high-voltage vehicle or of an electric vehicle. It also makes sense to have an appropriate warning beep sounding (in advance) so that the driver, where necessary, can react in the correct way.
The intelligent and anticipatory emergency brake assistant (IBA) prevents pile-ups and collisions with other objects by warning the driver in good time and also by triggering brake intervention right up to the point of a complete and autonomous emergency stop. Depending on the system in question, state-of-the-art camera systems and radar sensors monitor the front of the car. In parallel, messaging systems also help with the recognising of objects. If it is impossible to prevent a collision, airbags, seat belt tensioners and headrests are accordingly prepared and adjusted. Intelligent Brake Assist from Infiniti also integrates, for example, a collision warning system (Forward Collision Warning).
The avoiding of collisions is the key requirement of any driver assistance system. In principle, even when it comes to parking assistance, it is always a question of systems designed to avoid a collision. But, for a long time now, technological development has been taking things quite a bit further. While emergency brake assistants, lane-keeping or intersection assistants have been making their way into modern vehicles, the vehicle manufacturers in collaboration with partners from the field of research and development have been developing more intelligent systems in order prevent collisions right from the start. We are referring to ACA=Advanced Collision Avoidance Systems. And the challenge is this: the achieving of an extended perception of the vehicle environment by means of long-distance radar and the intelligent expanding of existing systems. The main protagonist in all this is the amount of information supplied by the relevant sensors and cameras (in future also information which will be provided by other vehicles) and its intelligent processing and translation into appropriate measures to be taken. It is also worth mentioning that special attention is being given to the possibility that other road users could become endangered through the intervention of an assistance system. Not all vehicles are equipped with the same technology and could then unnecessarily be exposed to danger by a third party. If this subject is taken further to the level of autonomous driving, problems such as the above-mentioned dilemma will surely play a major role in all discussions.
Cross Traffic Alert recognises critical cross traffic and warns the driver both visually and audibly. Almost all vehicle manufacturers offer such a cross traffic assistant, a tool which operates on the basis of a brake assistant and by using information from cameras (stereo cameras) or from radar sensors. Cross Traffic Alert is usually only active up until a defined speed is reached. The Hella subsidiary known as Hella Aglaia is an example of a company offering these technologies.
BMW has been using Cornering Brake Control since 1997 - other manufacturers have followed suit. As steering into a bend means that pressure on wheels on the inner side of the bend is lessened (depending on the bend radius and on the speed), it can happen that when brakes are applied the result could be 'over-revving' or 'over-braking'. The vehicle can then get into a skid. This can be prevented by Cornering Brake Control. Such a system with the assistance of the ABS control unit (the speed of every wheel is measured by the ABS sensors) controls every wheel individually, thus regulating brake pressure individually. The vehicle then, within the system limits, remains stable even when braking in bends. The driver is totally unaware of this control procedure.
Sensor-based systems (light sensors) aimed at recognising the ambient light situation form the foundation of automatic or interactive measures designed to regulate vehicle lighting. Oncoming traffic is just as relevant a factor in this equation as those vehicles driving ahead. A part is also played by the boundary between daytime and nighttime and also by the recognition of street lighting and reflective road signs.
It is the recognising of light sources that has, for example, given rise to all the following: high beam assistant, instrument or screen illumination (fully digital information displays with Volkswagen's Active Info Display as a good example) and intelligent assistance systems such as adaptive bend lighting, adaptive light distribution (selective illumination of danger zones, AFS - Advanced Frontlighting System) or the glare-free high beam (adaptive cut-off line). And all the time an increasing number of camera-based lighting control is being implemented. The Hella Group is an example of a supplier of such systems.
Turning left on (busy), partly confusing junctions is always a source of latent danger. Left Turn Assist recognizes oncoming vehicles and warns the driver visually and audibly. It can also trigger brake intervention in order to lessen or completely prevent a potential collision. Ultrasound sensors, radar sensors or intelligent camera systems are tasked with the job of recognising oncoming vehicles. (See also Car-to-Car Communication).
Tricky manoeuvring, for example in multi-level garages, or when lighting conditions are bad and especially as vehicles seem to be getting bigger, harbours the risk of scrapes or dents or even personal injury. With the help of environment sensors, Manoeuver Brake Assist is ready to monitor the immediate surroundings and, when and where necessary, intervenes by braking without delay. Manoeuver Brake Assist functions only at low speeds, e.g. below 10mph
Permanent steering-wheel movements and corrections carried out in a sloppy way - even on a straight stretch of road - are clear signs of overtiredness. The steering angle sensor collects signals and compares them (depending on the expansion level of the system) with GPS data on the route's topography. Duration of the journey, the time of day and the amount of mileage covered all play a role, too. 'Tired' drivers receive a warning in the form of a visual symbol or an audible signal, encouraging them to stop for 'a coffee break'.
So-called night view systems (thermal imaging cameras) are known for their use in a variety of applications. Binoculars which increase residual light can detect and identify, for example, wild animals even if it is completely dark. The prerequisite is that the necessary temperature differences are present. In 2005 Mercedes launched on the market the first night view system for car applications. Other manufacturers followed suit.
Today an infrared camera in conjunction with additional infrared headlamps enables objects to be registered and made visible: It captures not only people (people recognition) and animals but also (independent of temperature) branches and all kinds of other things. The image appears in the display of the vehicle or even better as a head-up display in the driver's field of vision.
The Night View assistant can be combined with brake, light, steering or chassis assistants. In this way active, safety-relevant corrections to the vehicle can be carried out in order to prevent accidents.
With the Park Assist and Garage Assist (also Park In/Park Out Assist or Garage Pilot), ultrasonic sensors (and also surround-view cameras or laser scanners) of each individual vehicle type recognise suitable lengthwise and crosswise parking bays and then measure distances. The difference between Park Assist and Garage Assist and the simple Park In/Park Out parking aid (Distance Warning System) or rear view camera with its visual parking assistance function is the automated support given by the vehicle during the parking procedure.
With the usual, partially active systems, the driver is informed about the parking options as he slowly drives by. If the driver then stops and activates the parking pilot, the assistant steers the car autonomously into the space. But the driver remains in the vehicle in order to accelerate and brake.
With the passive combination of Park Assist and Garage Assist, the vehicle steers into a parking space totally autonomously (even in multi-level garages) or into a garage and then out again. Garage Assist can recognise obstacles such as bicycles and is able to park in very narrow garages. The driver is not obliged to sit in the vehicle (passive) - on the contrary, he can control the relevant system from outside using a smartphone app and 'enjoy the parking show' so to speak. The only task left to him is the monitoring of the procedure and also a button in the app has to be permanently pressed otherwise the parking operation will be cancelled.
Voice control replaces the manual input of function instructions where either a keyboard and dials or a touchscreen on an information display is used. In an ideal situation all the following operations could be controlled in this way: programing the air-conditioning system, calling up diverse vehicle information, selecting music or checking a contact in your phone address book to make a phone call. The driver states his instructions and the relevant system reacts. Speech recognition systems of the first generation often had difficulties with the intonation and the regional linguistic imagery of drivers. Today language assistants and electronic 'translators' are not only integrated in our smartphones but they work well, too. And car systems are also more intelligent and more sophisticated.
From mid-2018 it is planned that the language assistant 'Alexa' available from an online dealer will be included in selected BMW vehicles. Other manufacturers plan similar projects. The actual control of vehicle functions is set to be complemented by the digital world.
Depending on individual vehicle manufacturers, Traffic Jam Assist combines the automatic distance control (part of ACC), the brake assistant and the lane tracking assistant. Radar sensors observe the (bumper-to-bumper) traffic in front of their own vehicle and a camera orients itself toward the road markings. The vehicle stays in its lane, keeps a defined distance and, if necessary, (within defined system limits) triggers a braking action which can lead to a standstill. Automatic starting up again in bumper-to-bumper traffic is also intended in many systems (cf. Car-to-Car Communication).
With the help of a camera mounted behind the windshield and which orients itself toward the road markings, Lane Tracking Assist sees to it that a vehicle remains in its lane. Differences in contrast between the road surface and lane stripes/hard shoulder stripe make this possible.
Systems are available with a haptic warning function such as a vibrating of the steering wheel (Lane Departure Warning) and there are also active systems (Lane Tracking Assist) which react by means of active steering intervention. If a vehicle leaves the ideal lane, first of all (depending on the system) a haptic or acoustic warning is given and then a 'gentle' steering intervention follows in order to bring the vehicle back 'on track'. When the vehicle actively and purposely departs from the lane, for example during an overtaking manoeuver using indicators, the system is suppressed.
At night the contrasts between the road markings and the road surface are slight and on some country roads there are no markings at all. When the detection limits have been reached, the lane tracking assistant or the lane departure warning system switches off. But the latest, intelligent systems with their state-of-the-art camera technology can even operate in dark and foggy conditions and they require fewer orientation guides (such as a median strip).
With Lane Change Assist, radar sensors on the vehicle rear end complement the driver's 'glance over the shoulder' when changing lanes. These sensors monitor the entire rear of the vehicle as far as the side parallel to the car including 'the blind spot' where other vehicles might be driving. If the driver indicates because he wishes to change lanes, a warning is issued if any other vehicles are approaching. This can be a visual warning in the side mirror or - depending on the system -also an audible one (See also Blind Spot).
The Tempomat (a brand name of the Daimler AG) is one of the oldest driver assistance systems. A comparable system from Chrysler first came on the market in the USA in 1958 (Cruise Control). The RPM was kept steady by means of a Bowden cable and thus the speed, too. In 1962 Mercedes in Germany followed this development up with the Tempomat.
Modern tempomats regulate the speed electronically, taking charge of acceleration and deceleration so that the speed is maintained as exactly as possible. Assistance systems like ACC ensure that the necessary safe distance is kept to the vehicle in front. The Tempomat is immediately shut down when the brake pedal is operated or when a distance regulation system kicks in.
Classically, the Tempomat is controlled by an additional pitman arm. In the new S-Class control is carried out via buttons on the steering wheel. (cf. Speed Limit Assist).
The term 'blind spot' refers to the area which, despite side and rear-view mirrors, for a short time cannot be seen by the driver. This normally concerns traffic behind or those vehicles in the process of overtaking on the left.
Blind Spot Assist calculates the position, the distance and also the direction of travel of other vehicles and gives a warning about vehicles driving on adjacent lanes. The system facilitates changing lanes and prevents accidents. BSD systems (Blind Spot Detection) operate by default with radar sensors located on both sides of the vehicle, sensors which can also be used for parking aids and for the Park In Assist system.
A traction control system (abbreviated to TCS) prevents spinning of the drive wheels when driving off or during rapid acceleration on unpaved roads. The system is called different names by the various vehicle manufacturers. Here are some examples: Automatic Stability Control (ASC) at BMW, Traction Control System (TCS) at Mazda or Traction Control (TRC) at Toyota. Most of the other manufacturers, however, use the abbreviation TCS for traction control.
Traction control can either be put into practice by brake intervention or by intervening in engine control. Control signals are sent by the relevant ABS sensors (or RPM sensors) which, within defined system limits (slip angle, maximum 10-20 degrees), signal the slip slope of the wheels (ratio of torque to wheel slip). The system functions with front, rear or all-wheel drives.
With the help of intelligent, image-processing software, camera systems can recognise important road signs such as speed restrictions (See Speed Limit Assist), overtaking restrictions or construction zone signs. The driver is warned visually and audibly. In this way, drivers can be prevented from missing a vital road sign.