Active safety: Warning and intervening

Mar 7, 2011
  • Help in an emergency: ten new driving assistance systems
  • Holistic approach: “Real Life Safety”
Preventing accidents and minimising the consequences thereof: this is the holistic approach taken by those working in Mercedes-Benz safety research, which the company terms “ Real Life Safety”. The basis of this is formed by what the in-house engineers know as “driver-fitness safety”, alongside ride and seating comfort, plus quiet-running characteristics, such as effective headlamp and windscreen wiper systems and simple and safe operation. Safe handling that has no nasty surprises in store comes courtesy of advanced chassis systems, which for years now have also been fitted as standard with ESP®, developed by Mercedes-Benz. In addition to this there are the PRE-SAFE® systems which can warn, support and protect the driver when a concrete risk of accident has been detected.
An important anticipatory role is increasingly being played by a large number of assistance systems which ease the burden on the driver – especially in critical situations. This is where Mercedes-Benz uses its unique position in the segment of luxury vehicles as a spearhead of technological development. New technologies are then integrated into the high-volume model series as quickly as possible. The best example of this process of democratisation is the new-generation C-Class. It is now offering no less than ten new assistance systems, some of which only entered series production in the luxury class in the past year.
Warning and intervening: the new driving assistance systems
With a total of ten new driving assistance systems ranging from ATTENTION ASSIST drowsiness detection to DISTRONIC PLUS proximity control, the C‑Class reaches a new level of safety. The assistance systems are based on the latest radar, camera and sensor technology, and cover frequent accident causes such as driving too closely, fatigue and darkness. The new assistance systems, some of which only warn and some which actively intervene in hazardous situations, at a glance:
  • Adaptive Highbeam Assist
  • Active Lane Keeping Assist
  • Active Blind Spot Assist
  • Speed Limit Assist
  • PARKTRONIC including Parking Guidance
  • PRE-SAFE® Brakeincluding BAS PLUS
  • Lane Keeping Assist
  • Blind Spot Assist
Electronic helpers: the new assistance systems in the C-Class
Adaptive Highbeam Assist. When vehicles are detected ahead of or approaching the vehicle, this system automatically dips the beams and adjusts the range of the headlamps appropriate to the distance. This means that main beam can be used more frequently.
Active Lane Keeping Assist. The system kicks into action if the Mercedes-Benz vehicle inadvertently drifts over a solid line to the right or left of a lane. In such a case, a warning sign in the instrument cluster and vibration of the steering wheel give the driver warning. If the driver does not heed the warning in the case of the solid line, Active Lane Keeping Assist can use the ESP® to brake the opposite wheels and thereby prevent the vehicle from crossing the solid line. The Lane Keeping Assist, which warns but does not actively intervene, is available as a favourably-priced alternative.
Active Blind Spot Assist. It warns the driver when changing lanes if a risk of collision is detected due to another vehicle in the neighbouring lane being in the blind spot of the exterior mirror. If the driver ignores the warning and nevertheless initiates the lane-changing manoeuvre, the Active Blind Spot Assist intervenes. By applying braking force to the wheels on the opposite side of the vehicle, a yaw movement is created which counteracts the collision course. The Active Blind Spot Assist was recently awarded the “Yellow Angel” prize for being a pioneering innovation by a jury of experts from the ADAC, the German automobile association and the biggest of its kind in the world. The favourably-priced alternative is the Blind Spot Assist; it warns the driver but does not actively intervene.
ATTENTION ASSISTwarns drivers when it detects that they are over-tired. Studies have shown that around a quarter of all serious motorway accidents are caused by drowsy drivers, making this factor an even bigger cause of accidents than drink-driving. With ATTENTION ASSIST (standard for Elegance and Avantgarde), Mercedes-Benz is therefore making another important contribution towards helping to avoid accidents: it employs high-resolution sensors to observe driver behaviour and can recognise whether the driver is tired or not paying attention, based primarily on steering wheel movements.
BRAKE ASSIST PLUS: this system is able to recognise an impending rear-end collision using radar sensors. It calculates the necessary degree of braking assistance and makes it available immediately when the driver presses the brake pedal.
DISTRONIC PLUS: the radar-based proximity control supports the driver at speeds between zero and 200 km/h by automatically adjusting the distance to the vehicles in front. In doing so it is able to apply the brakes to bring the vehicle to a complete standstill and also accelerate it again. As a result, the system is also particularly convenient in stop-and-go traffic. If the system detects that the distance is being reduced too quickly, it warns the driver with both visual and acoustic signals. The control system has also been refined even further through the inclusion of information from digital maps.
Speed Limit Assist: a camera fitted behind the windscreen detects speed limit signs at the roadside and compares this data to information contained in the GPS system. The relevant speed limit is then displayed in the instrument cluster.
PARKTRONIC including Parking Guidance:ultrasonic sensors measure the length of parking spaces as the car drives past; the cockpit display provides a schematic representation of the recommended parking manoeuvre. Ultrasonic sensors then support the driver whilst parking.
PRE-SAFE® Brake:autonomous braking if acute danger of an accident is detected. At first the driver is given both an acoustic and an optical warning if the system identifies that there is a danger of collision. If the driver does not react to this, the system brakes the vehicle autonomously. This occurs in two stages: around 1.6 seconds before the calculated impact point the system decelerates the car with around 40 percent (approx. four m/s²) of the maximum braking power, gives the driver an additional, haptic warning of
the impending impact and as a precaution activates the reversible PRE-SAFE® occupant protection systems. If the driver still fails to react, the PRE-SAFE® Brake activates the maximum braking power around 0.6 seconds before the now unavoidable collision – this emergency braking can greatly reduce the severity of the impact. The system therefore acts like an “electronic crumple zone”, offering the car occupants even greater protection. The PRE-SAFE® Brake is active at speeds of between 30 and 200 km/h when moving vehicles are detected in front of the car. The system also reacts if the car approaches a stationary queue of traffic, providing its speed is below 70 km/h.
Other helpers:
ADAPTIVE BRAKE: this Mercedes-Benz brake system offers assistance functions for greater safety and comfort, such as a HOLD function when waiting at traffic lights, and Hill-Start Assist which can help prevent rolling backwards when moving off on a downhill gradient.
Headlamp Assist:a sensor on the windscreen registers the lighting conditions. As a result, the headlamps can be turned on automatically when darkness falls.