Passive safety: Nine airbags as standard

Drivers of Mercedes vehicles are safer on the road than drivers of other car brands. This is the result of a study by Mercedes-Benz accident research based on official, anonymous data samples from the Federal Office of Statistics. Having looked at 18,748 accidents resulting in personal injury during the period from 2003 to 2007, the study found that the risk of being seriously or fatally injured as the driver of a Mercedes is 9.6 percent lower than for vehicles of other brands. The result represents clear evidence of the contribution made by the passive safety systems of Mercedes-Benz to reducing the consequences of an accident.

The main prerequisites for this include a stable body structure (see the section entitled "The Bodywork") as well as a whole host of sophisticated restraint systems. With nine airbags fitted as standard, not to mention four seat-belt tensioners and belt-force limiters as well as NECK-PRO crash-responsive head restraints for the driver and front passenger, the new CLS offers an even more extensive package of safety equipment than the previous model. The airbags, which can deploy in a matter of milliseconds in the event of an accident, include two adaptive airbags for the driver and front passenger, a kneebag for the driver, two sidebags in the front-seat backrests and two large windowbags which extend from the A-pillar to the C-pillar during a side impact. For the first time, pelvisbags are included as standard for front seat passengers, which in the event of a side collision can help to reduce loads in the pelvic area. Sidebags are also available for the rear as an optional extra, which means that the new CLS makes a total of eleven airbags available for occupant protection.

Three-point automatic safety belts with belt tensioners and belt force limiters are fitted as standard for the driver, front passenger and rear passengers. Mercedes-Benz is offering adaptive belt force limiters for the rear seats as an option. These adapt to the size of passengers automatically. The system detects whether the rear seat passenger is large or small as soon as the seat belt is put on, based on the length of the pulled-out seat belt, and can adapt its protective effect accordingly. The maximum belt force is activated immediately if the rear passenger is large in size, while in the case of smaller occupants the force exerted by the belt is initially set to a lower level.

For the first time Mercedes-Benz is offering the CLS with ISOFIX, the international standard securing system for child seats. The mechanism is fitted as standard and comprises two retaining brackets in each rear seat position, in the gap between the back rest and seat cushion, as well as an additional third anchor point, the so-called top tether.

NECK-PRO is the name Mercedes-Benz has given to a crash-responsive head restraint whose development, like that of PRE-SAFE and other Mercedes-Benz innovations, is based on analyses of real accidents. NECK-PRO is an effective means of reducing the risk of whiplash injuries during a rear-end collision. If the sensor system detects a rear-end collision with a defined impact severity, it releases pre-tensioned springs inside the head restraints, causing the head restraints to move forward by about 40 millimetres and upwards by 30 millimetres within a matter of milliseconds. This means that the heads of the driver and front passenger can be supported at an early stage.

The occupant protection system PRE-SAFE: preventive measures reduce the consequences of an accident by up to 40 percent

In 2002 Mercedes-Benz became the first automotive brand to offer an anticipatory occupant protection system which can initiate measures to protect the occupants of the vehicle if there is an imminent risk of an accident: PRE-SAFE. Mercedes-Benz's intelligent approach takes its lead from nature: PRE-SAFE activates protective measures for the car occupants as a precaution, just as living things react instinctively and search for cover when they are in danger. The aim is to prepare the occupants and vehicle for an imminent collision so that the seat belts and airbags are able to fulfil their protective function to the full during an impact. What's more, the PRE-SAFE protective measures are reversible: if the accident is averted, the advance tensioning of the seat belts is halted automatically and the occupants are able to reset the positions of the seats and the sliding sunroof. The anticipatory occupant protection system is then ready for action again straightaway.

Early accident detection is possible because PRE-SAFE is an intelligent synergy of active and passive safety. It is linked to Brake Assist and the Electronic Stability Program (ESP), whose sensors detect potentially critical driving situations and send the relevant information to the electronic control units within a matter of milliseconds.

The new Mercedes CLS is able to offer even more preventive measures ahead of an imminent accident than ever before:

Whereas PRE-SAFE previously responded to emergency or panic braking - in other words when the driver hit the brake pedal reflexively - the system in the new CLS can also be activated if the optional DISTRONIC PLUS has detected an impending collision with the aid of short and long-range sensors, and a certain level of delay in braking has been exceeded. The occupants are prepared for the collision by tensioning of the seat belts and repositioning of the front-passenger seat (if the seat memory function is installed) - which is also optionally available with fully electric seat adjustment - enabling the seat belts and airbags to offer the best possible protection.
The active multicontour seat (optional extra), ensures that the driver and front passenger are seated even more securely, thereby limiting dangerous whiplash movements by the upper body in the event of an accident. If the PRE-SAFE control unit detects a critical driving situation, it immediately activates the air chambers in the seat cushions and backrests. These then envelope the seat occupants and give them support.
Tests at the Mercedes-Benz Technology Center have shown that this PRE-SAFE function and preventive belt tensioning increases the distance between the shoulder and the inner door lining by up to 40 millimetres at a lateral acceleration of 0.6 g. This enables the sidebag to fulfil its protective function even more effectively.

PRE-SAFE triggers the following anticipatory measures:

PRE-SAFE when braking in an emergency
Driver and front-passenger seat belts are tensioned
The seat fore-and-aft adjustment, and the cushion and backrest angles on the front passenger seat are moved to the best possible positions for crash conditions
Bolsters in the seat cushions and backrests of the multicontour front seats can be inflated
PRE-SAFE if high lateral acceleration is detected
The side windows can be closed
The sliding sunroof can be closed

When installed in combination with DISTRONIC PLUS, PRE-SAFE also uses the information provided by the short-range radar sensors in the front bumper to tension the front seat belts at the very last moment before an unavoidable collision, thus reducing the forces exerted on the driver and front passenger during the crash. This PRE-SAFE function is literally the "ultima ratio" of anticipatory occupant protection, since the accident occurs around 200 milliseconds later.

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