Mercedes-Benz C-Class Estate - Safety

Published: 21st February 2008

The New Mercedes Benz C Class Estate with the tailgate open

The New Mercedes-Benz C-Class Estate < part two

Nothing beats experience – except even more experience – and 60 plus years of expertise in vehicle safety continues to build with every new model launch. The new C-Class is no exception and an exhaustive programme of impact analysis, including more than 100 crash tests and around 5500 computerised simulated impacts have resulted in an immensely safe structure.

The new bodyshell boasts a 12 per cent increase in torsional stiffness, larger dimensions and enhanced safety performance, yet it weighs 4 kg less than its predecessor. That’s down to greater use of high-strength structural adhesives and an intelligent mix of aluminium and high strength steel alloys – around 70 per cent of the sheet metal panels are made from these high-tech grades of steel, while for around a fifth of all parts, ultra-high-strength steels have been deployed.

Like the Saloon, the Estate features four independently acting impact levels which enable forces to be distributed over a wide area while by-passing the passenger cell which deforms only slightly even in a serious accident. As well as robust aluminium front cross member and side members which extend forward to direct impact forces into the side structure, firewall and transmission tunnel, there’s now a subframe made of high-strength steel which serves a similar purpose.

Special struts in the wheel arches prevent the passenger cell from dropping during a collision and on the driver’s side there’s also an X-strut which connects the shock absorber tower with the robust cross member beneath the windscreen and supports it. During an impact, this reduces the rearwards displacement of the shock absorber tower and the main brake cylinder behind it, preventing the pedal cluster from being pushed into the interior.

As only a very small crumple zone is available during a side collision, side impact forces are dispersed over a wide area by quadruple-shell B-pillars and sills partly manufactured from ultra-high-strength steel. The impact forces are transferred from the B-pillar to the opposite side of the vehicle first and foremost via the transversely rigid seat and the centre console. Accordingly, the seats of the C-Class are equipped with tubular sections and impact-absorbing elements in the side mouldings. A further load dissipation path runs from the base of the B-pillars to the cross member under the seats and the transmission tunnel braces.

An effective crumple zone is also included at the rear and consists of multi-piece side members and a bolted-in section that acts as a cross member capable of absorbing large forces and distributing them into the body structure.

The C-Class Estate has yet to be tested by Euro NCAP but its Saloon stablemate passed the crash tests with flying colours, achieving five stars, making it one of the safest cars on the market.

Pedestrian protection: deformation zones under the bonnet

A number of features help to minimise pedestrian injury in the event of an accident including a large deformation space beneath the bonnet; smooth body surfaces; energy-absorbing bumpers; laminated glass windscreens; folding exterior mirrors; rounded door handles; recessed windscreen wipers and a front bumper featuring a flush, foam-filled spoiler lip which provides a pedestrian with uniform support at an early stage in a collision.

Multiple restraint systems

Occupants are protected by a total of seven airbags as standard: two stage front airbags, side airbags, full length curtain airbags and a driver’s kneebag. The driver, front passenger and the passengers on the outer rear seats also benefit from belt tensioners and belt force limiters.

Neck-Pro head restraints move upwards and forwards to cushion the heads of the driver and front passenger at an early stage in a rear-end collision to guard against the risk of whiplash, and are activated when sensors detect a rear-end collision of sufficient severity.

The two outer rear seats are equipped with ISOFIX child seat fixings, while there is the option of integrated child seats which fold out of the rear bench seat cushion at the push of a button, and now offer the benefit of a wraparound head restraint (£270).

Other items provided as standard which make a vital contribution to accident prevention include flashing brake lights and Electronic Stability Program (ESP®).

If the driver is obliged to brake sharply from a speed of over 30 mph, or if Brake Assist comes to the driver's aid in an emergency situation, the brake lights flash rapidly to warn traffic behind. Studies show that drivers’ braking reaction time can be shortened by up to 0.2 seconds on average if a flashing red warning light is substituted for a conventional brake light, which equates to approximately 5.50 metres at 60 mph, or about the length of a family car.

ESP® now incorporates additional functions including a trailer stabilisation feature and a new control logic which assists the driver even more effectively in critical cornering situations by triggering precisely metered braking pulses on up to three wheels. It will also monitor tyre pressures and warn the driver if there is a sudden loss in pressure.

Pre-Safe® standard on all models

The anticipatory occupant protection system Pre-Safe® gives the new C-Class Estate an edge over other models in this segment. Pre-Safe® makes use of the moments before an imminent accident to prepare the vehicle and its occupants for a collision, considerably reducing the loads exerted on the passengers upon impact.

It detects critical driving manoeuvres involving either high lateral or extreme linear forces using feedback from the ESP® and Brake Assist systems, and triggers a suitable response:

During emergency or panic braking with Brake Assist, Pre-Safe® pulls the seatbelts taut and starts to bring an unfavourably adjusted front passenger seat into a better position – provided the car is equipped with the electrically adjustable front passenger seat with memory function. The system corrects both the backrest and seat cushion angles as well as the height and fore-and-aft adjustment of the seat as required.

If there is a danger of skidding owing to heavy understeering or oversteering, the side windows and sliding sunroof (optional) begin to close as a precaution. Closed side windows are better able to brace the windowbags which deploy during a side impact. This preventive measure also lessens the risk of the occupants being thrown from the vehicle or objects penetrating into the interior during a crash.

Intelligent lighting according to the driving situation

The optional Intelligent Light System, the only system of its kind in this market segment at the current time, features five different lighting functions configured for different driving and weather situations (£1,055 for SE models, and £975 for Elegance and Sport). A powerful bi-xenon light package is included in the price of the Intelligent Light System or is available separately, priced £725, and includes a cornering light function, headlamp wash and LED rear indicators.

Country mode illuminates the verge more broadly and brightly;
in motorway mode the range of vision is increased by up to 60 per cent above 55 mph, while at 70 mph the beam of the bi-xenon module on the nearside is elevated slightly;
enhanced fog lamps, activated at speeds below 40 mph when the rear fog lamp is switched on, improve driver orientation – the bi-xenon headlamp on the nearside is pivoted outwards by eight degrees, while lowering its beam of light at the same time which illuminates the left half of the road more brightly and reduces the degree of glare from light reflected back by the fog.
Depending on the steering angle, yaw rate and vehicle speed, the active light function pivots the headlamps sideways by up to 15 degrees in fractions of a second to greatly improve road illumination – on a long sweeping bend with a radius of 190 metres, the driver is able to see 25 metres further;
finally the cornering light function integrated into the fog lamps in the bumper improves safety at junctions, when turning into side roads and on tight bends.

The New Mercedes-Benz C-Class Estate > part four