Safety - at the heart of all our thinking


The Integral Safety Concept from Mercedes-Benz divides vehicle safety into four phases:

Virtually no other area inspires the Mercedes-Benz engineers to produce such consistently impressive results as much as research into new safety technologies. The first important safety milestone was reached back in the 1950s with the development of the passenger safety cell, invented by Béla Barényi. Today it is just one of many components of the Integral Safety Concept which edges Mercedes-Benz vehicles ever closer to our vision of accident-free driving.

Phase 1: safe driving

The majority of accidents start long before the actual collision: with a lapse in concentration, poor visibility or hazards which cannot be anticipated. That's why the Mercedes-Benz safety concept employs a range of measures to support stress-free driving in everyday operation and to help you bring critical situations under control.

DISTRONIC PLUS proximity control (optional)[1]

DISTRONIC PLUS proximity control helps the driver to maintain a specified (timed) distance from the vehicle ahead when travelling at speeds of 0 to 200 km/h.

Adaptive brake lights, flashing

In emergency or panic braking, specific criteria such as brake pressure or road speed trigger the activation of the adaptive brake lights. When activated, the brake lights flash to give drivers behind even better warning of the risk of a rear-end collision.

Studies have shown that drivers' brake-activation response times are shortened by up to 0.2 seconds when emergency braking is indicated by a flashing red warning signal instead of conventional brake lights. At a speed of 80 km/h this translates into a stopping distance shortened by about 4.40 metres. The brake lamps flash at a frequency of about 3 Hertz (if equipped with incandescent bulbs) or about 5 Hertz (if equipped with LEDs). This frequency range has proved itself to be especially effective in tests.

As soon as the vehicle travels at less than 10 km/h or has come to a stop, or if Brake Assist is no longer active and the vehicle deceleration rate drops below 6.5 m/s² for 150 milliseconds the brake lamps will light up steady again.

The adaptive brake lights are triggered when:

  • the initial speed is more than 50 km/h, BAS Brake Assist has detected an emergency stop situation or the braking pressure is more than 75 percent of maximum.
  • As soon as the vehicle comes to a stop the warning flashing light is automatically activated for good measure, if the speed at the start of the brake application was higher than 70 km/h.
Active Parking Assist, including PARKTRONIC (optional)

Active Parking Assist makes a major contribution to safe and comfortable driving. It helps the driver to find a suitable parking space - either parallel on a road or at 90 degrees into a car park space - and helps him to park by actively steering the vehicle. The integrated PARKTRONIC can warn drivers if there are hidden obstacles in front of the car or behind. Active Parking Assist uses two ultrasound sensors in the front bumper to identify suitable parking spaces when the vehicle is travelling at a speed of up to 35 km/h.

The automatic parking space search function is indicated by a "P" symbol in the instrument cluster. If Active Parking Assist has found a parking space, an arrow appears next to the "P". By default, Active Parking Assist searches for parking spaces on the right-hand side of the road. If the indicator on the driver's side is active, parking spaces on the left-hand side are also detected.

The driver starts the parking manoeuvring process by stopping ahead of the indicated parking space, selecting reverse and confirming the prompt which appears in the instrument cluster. Active Parking Assist then takes over the steering at up to 10 km/h. The driver only has to operate the clutch (in vehicles with manual transmission) and the accelerator and brake. The parking manoeuvre is completed in a maximum of 5 moves. The final parking move is indicated by the message "Parking Assist complete" in the display. This message is accompanied by an acoustic signal.< PARKTRONIC gives visible and audible signals to warn of obstacles it detects in front of the vehicle and behind it. It is active up to a speed of about 16 km/h.


The ATTENTION ASSIST function is particularly helpful on long journeys and when driving at night; the system warns the driver if it detects signs of failing attention and increasing weariness. This driving assistance system can warn the driver when it identifies typical signs of fatigue, which in turn improves handling safety.

ATTENTION ASSIST continuously analyses driving behaviour and steering movements. If the system detects certain steering patterns that frequently accompany drowsiness, it warns the driver visually by displaying the "coffee cup" symbol in the instrument cluster at the same time as emitting audible signals. ATTENTION ASSIST can be activated and deactivated in the main menu of the instrument cluster under "Assistance systems". When switched on, it is active at speeds between 80 and 180 km/h.

Bi-xenon headlamps (optional)

The bi-xenon headlamps are a further development of the well-known xenon headlamps, offering xenon technology for both low and high-beam. LED technology is used both for the daytime running lamps integrated in the headlamps and for the bicolour tail lamps.

  • Enhancing safety: the bi-xenon headlamps provide outstanding brightness values in comparison with conventional headlamps. The main-beam headlamps have a markedly larger light range and provide clearer and wider illumination of the road surface. The automatic headlamp range adjustment feature ensures oncoming traffic is not dazzled.
  • Thinking ahead: xenon bulbs and LEDs have a long operating life. The headlamps remain clean at all times thanks to the intergral headlamp cleaning system.
  • Shows character: The appointments, which have been carefully matched to each other, give the new CLA a particularly striking light design.
ADAPTIVE BRAKE system with HOLD function, brake drying function and Hill-Start Assist

The standard ADAPTIVE BRAKE system improves driving comfort and safety. On the one hand it helps with braking in critical situations - within the limits of physics - using the basic ABS anti-lock braking system function; on the other, convenience functions support the driver in day-to-day driving situations.

  • Supporting HOLD function: the HOLD function, which is activated by briefly depressing the brake pedal, prevents unintentional rolling when stopped at a traffic light or in stop-and-go traffic
  • Additional help: the Hill-Start Assist function prevents the vehicle from rolling back unexpectedly on inclines when moving from the brake to the accelerator pedal.
  • For an even quicker response: With the "Priming" option, the brake linings on the brake discs are primed as soon as the driver takes his foot off the accelerator quickly.
COLLISION PREVENTION ASSIST collision warning including Adaptive Brake Assist

Too small of a gap between vehicles is the main cause of severe accidents. The newly developed radar-based collision warning system COLLISION PREVENTION ASSIST can improve safety and ride comfort by warning drivers when the gap to preceding vehicles is too small and can support the driver’s braking when it detects danger.

When travelling at speeds of more than 7 km/h, the system can recognise insufficient gaps between the vehicle and vehicles ahead. When the system detects the danger of a rear-end collision it can issue a visual and acoustic warning to the driver.

If the system detects a danger and the driver applies the brakes at the same time, Adaptive Brake Assist can intervene for good measure: It then provides precisely the right amount of brake pressure that is needed ideally to avoid an impending collision. COLLISION PREVENTION ASSIST is an innovative component of the integral safety concept from Mercedes-Benz.

ESP® Electronic Stability Program

In critical situations, the Electronic Stability Program (ESP®) can help to stabilise the vehicle by applying a braking force to individual wheels, and adjusting engine performance.

If the ESP® system detects a critical situation, it applies the brakes systematically to one or more wheels according to the situation. Should the system consider it necessary, it will also make an automatic adjustment to engine torque. In this way ESP® helps the driver to stabilise the vehicle within the laws of physics – particularly when cornering and during sudden evasive manoeuvres.

  • Central feature: the yaw-rate sensor continuously monitors vehicle movement around its vertical axis and the ESP® system compares the actual values measured with the optimum desired value, based on the driver's steering movements and the vehicle's speed. The instant the vehicle deviates from the ideal line, ESP® intervenes by working to counteract any swerving movements as they occur.
  • The right engine output at all times: the integral acceleration skid control (ASR) function also controls traction by intervening in the engine management so as to reduce engine power output to prevent the wheels from spinning.
  • Enhanced safety: ABS as an integral component of ESP® helps to prevent the wheels from locking and to maintain their steering function.
  • Additional components: ESP® rounds off the functions of the anti-lock braking system (ABS) and acceleration skid control (ASR) to help with driving stability.
Headlamp Assist

The headlamp assist system reduces the strain on the driver by automatically switching on low-beam headlamps, tail lamps and number plate illumination when it gets dark outside. The assistance system performs this task even when it’s raining or snowing via a signal from the rain sensor.

The Headlamp Assist system uses a light sensor to measure the light level of the surroundings. If light levels fall below a certain level, low-beam headlamps are switched on. If the light intensity of the surroundings rises again, the low-beam headlamps are switched off again. The system ensures the necessary level of illumination for the vehicle at all times, contributes towards handling safety – in particular under rapidly-changing light conditions (e.g. driving into a tunnel or multi-storey car park) – and enhances the driver’s comfort.

Intelligent Light System (optional)

The Intelligent Light System – as an active component of the safety concept – ensures the best possible visibility in all weather conditions and the most diverse traffic situations. With oncoming traffic, illuminated road users, on bends, in fog or on free stretches of road, the system adapts to the situation and adjusts the characteristics of the light individually to that situation.

  • Bringing light to the darkness: in the "country light" mode the light from the low-beam headlamps is distributed such that the edge of the carriageway is significantly better illuminated than with conventional headlamps.
  • Increasing dynamically: the motorway mode is automatically activated in two steps: from 90 km/h the system boosts the power of the bi-xenon lamps. From 110 km/h the setting of the headlamp on the inside of the traffic lane also changes to illuminate the entire width of the lane uniformly for a distance of up to around 120 metres.
  • Enhancing safety: with the expanded fog lamp the system improves the visibility when fog is present. The left bi-xenon headlamp tilts outwards and the light cone is simultaneously lowered downwards. This light function is automatically activated as soon as the rear fog lamp is switched on and the vehicle is not travelling faster than 70 km/h.
  • Following every bend: The active light function follows the driver's steering angle: sensor data on the steering angle, yaw rate and vehicle speed allow the bi-xenon headlamps to pivot to the side in fractions of a second as soon as the vehicle starts to corner. With the cornering light function the cornering lamps automatically switch on when the driver activates the indicator or turns the steering wheel.
  • Extended vision without having to push a button: The Adaptive Highbeam Assist provides the best possible low-beam headlamp range. This makes it possible to see pedestrians, cyclists or obstacles at an earlier stage than with conventional low-beam headlamps. A camera is used to control headlamp range adjustment and the main beams in such a way that the road receives the best possible illumination in line with the current driving scenario and the road users ahead If the system registers oncoming vehicles or vehicles ahead, it continuously adjusts the beam range to the distance so that the cone of light ends before it meets these vehicles. The high beam automatically switches on when no other road users are detected. A special feature is the gentle transition from one type of light to the other without an abrupt change in intensity.
  • Enhancing the own visibility: The LED daytime driving lights are integrated into the headlamps and make it easier for other road users to spot the vehicle; the integral headlamp cleaning system minimises dirt build-up on the lights. Additionally, the position light at the front as well as the bicolour tail lamps, brake lamp, indicators, reversing light and the rear fog lamp all use LED technology.
Reversing camera (optional)

The reversing camera is switched on automatically when reverse gear is engaged. It helps the driver to reverse into parking spaces, both parallel spaces or at 90 degrees. Static and dynamic guide lines show the driver the steering angle and distance. The reversing camera is built into the tailgate handle and monitors the area directly behind the vehicle.

Through a new look with digital image transfer and additional electronic zoom functions, an optimum image is ensured in all driving situations. When manoeuvring, the driver can select the "back-in" mode, in which dynamic guide lines indicate the relevant path of the vehicle.

If the vehicle is fitted with a trailer coupling, a further mode is made available. The driver is initially assisted, in "Back-in" mode, in backing up towards the drawbar properly aligned through the marking of the middle of the axle. Once he is close to the trailer, "Zoom mode" enables him to align the vehicle with absolute precision. The driver is helped by a dynamic guide line which shows the path of the trailer coupling at the every steering angle.

Lane Keeping Assist (optional)

The Lane Keeping Assist makes a significant contribution to road traffic safety. It can warn the driver by means of a discreet vibration of the steering-wheel if the vehicle unintentionally leaves its lane, drifting across lane markings that have been registered by the system. If the turn indicator is actuated beforehand or the steering wheel is clearly turned, the system assumes that the lane change is intentional and does not emit a warning.

Blind Spot Assist (optional)

Blind Spot Assist helps the driver to avoid potentially critical situations by monitoring the areas to the left and right of the vehicle when changing lanes. If the system detects another vehicle within the monitoring range, a hazard warning triangle lights up in the corresponding exterior mirror. An additional audible warning sounds if the driver now sets the turn indicator to indicate he intends to change lane.

Phase 2: in critical situations

Mercedes-Benz stands for automotive safety. That's why our vehicles can support their passengers even in critical driving situations, so that every journey is as safe as it can possibly be.

Anti-lock braking system (ABS)

The anti-lock braking system (ABS) can enhance driving safety, especially in critical braking situations. . When braking, ABS can prevent the individual wheels from locking by modulating the braking pressure of the individual wheels.

This ensures that the vehicle remains directionally stable and can be steered while maintaining maximum braking power.

In other words: ABS allows the driver to brake and steer simultaneously – allowing precise evasive manoeuvring – in order to avoid an accident.

Acceleration skid control (ASR)

The acceleration skid control (ASR) ensures that the wheels do not spin when accelerating. Especially when moving off on snow, ice and loose chippings, the acceleration skid control prevents individual wheels from spinning and the vehicle from sliding out to the side.

The system uses speed sensors to monitor the slip characteristics of the wheels. If the system senses a wheel is starting to spin, the acceleration skid control corrects the wheel speed by braking and intervening in the engine management system, thus reducing the wheel slip and wheel spin.

BAS Brake Assist system with braking power assist in detected emergency stops

Brake Assist can detect emergency braking situations based on the speed with which the brake pedal is depressed and assists the driver by increasing the brake pressure. The system interprets a certain speed at which the brake pedal is depressed as an emergency situation, and automatically builds up maximum braking power within fractions of a second.

Brake Assist is integrated into the Electronic Stability Program (ESP®) and uses its technology to adjust the braking pressure, thereby eliminating the need for additional components. A sensor permanently monitors the speed at which the brake pedal is depressed and transmits this data to the electronic control unit.

If an unusually high pedal speed is registered, the system concludes that there is an emergency braking situation. The system then helps the driver to perform an emergency stop by automatically increasing brake pressure in the wheel brake cylinders. ABS continues to precisely meter the braking power up to the slip threshold, which ensures that steering control is maintained. Once the driver releases the brake pedal, automatic brake boosting ceases immediately.

PRE-SAFE® occupant protection system (optional)

When the PRE-SAFE® system detects the typical risks of an accident, it can activate preventive safety systems depending on the driving situation and vehicle equipment. These can help to reduce the risk of injury to the vehicle occupants.

The PRE-SAFE® system is able to recognise an impending accident because it represents a synergy of active and passive safety features unique to this vehicle class: it systematically accesses the sensors of existing systems such as ESP® or BAS their sensors are able to detect typical critical driving situations and provide the appropriate information to the PRE-SAFE® system, thereby enhancing the standard safety systems.

Examples include the securing of the driver and front passenger in their seats at an early stage by electric belt tensioners to prevent undesirable body movements; or the almost complete closure of the side windows and sliding sunroof to protect occupants from any objects entering the vehicle.

Phase 3: in an accident

Cars from Mercedes-Benz have a host of safety systems to prevent accidents. Should the worst come to the worst, however, a number of occupant safety measures are activated. They include protection for the vehicle occupants as well as for other road users.

Airbags for driver and front passenger

The driver and front passenger airbags help to protect the upper torso and head in a collision – as well as providing additional stability for the entire body. They can also mitigate the severity of injuries sustained in an accident. If the crash sensors detect a collision from a specific direction and it exceeds a given impact severity, the airbags are deployed.

The gas generators of both airbags work in two stages. Both stages are activated depending, amongst other factors, on the braking force registered. Depending on the predicted severity of the impact, the first stage of the gas generator is initially activated and the airbag only partially filled. If a higher severity of impact is predicted, the second stage of the gas generator is activated after a slight delay and the airbag is completely filled.

Automatic child seat recognition in front passenger seat (optional)

The automatic child seat recognition system detects child seats with a transponder from the Mercedes-Benz accessories range and automatically deactivates the front passenger airbag.

An aerial integrated in the front-passenger seat sends signals. If special child seat models from the Mercedes-Benz accessories range are fitted, transponders integrated in the child seat detect these signals and send a feedback signal. Based on this feedback signal, the automatic child seat recognition system deactivates the front-passenger airbag. An indicator lamp lights up to confirm that the airbag has been deactivated. The belt tensioner and the other airbags on the front-passenger side – such as the sidebag (combined thorax/pelvisbag) and windowbag - remain active in order to protect the child. The front-passenger airbag is reactivated automatically after the child seat has been removed.

Pedestrian protection (active bonnet)

The active bonnet can reduce the risk of injury to pedestrians and cyclists. If the system registers a collision with a pedestrian or cyclist, the actuator explodes and causes the rear section of the bonnet to rise up by approximately five centimetres using spring force. This produces additional deformation space to absorb the impact energy, thereby reducing the risk of serious injuries.

ISOFIX child seat attachment points in rear

The ISOFIX child seat attachment system is a quick, convenient, non-vehicle-specific system conforming to ISO standards. In conjunction with the TopTether anchor kit, it allows quick and easy child seat anchorage in the rear. Its fixed anchorage points ensure a high degree of protection in the event of an accident.

A special ISOFIX child seat engages in the attachment points housed in the lower area of the backrest. This creates a rigid connection with the vehicle structure, ensuring that seat movements caused by slack or incorrectly fitted seat belts can be avoided. TopTether is an additional safeguard attached behind the rear head restraints. It further reduces the risk of the child seat tilting forwards in the event of a crash.

Kneebag for driver

The kneebag on the driver’s side helps to protect the legs during impact and also stabilises the entire body. It can thus help mitigate the severity of injuries sustained in an accident. If the crash sensors detect an accident from a certain direction and that exceeds a given severity, the kneebag is deployed.

Sidebags for driver and front passenger (combined thorax/pelvisbags)

The standard-fit sidebags for the driver and front passenger (combined thorax/pelvis bags) provide protection for the occupants’ upper torso and pelvis area in a side impact, and also afford additional stability to the entire body. They are thus able to guard against severe injuries in an accident.

Sidebags in the rear, left and right (optional)

The sidebags in the rear are stored behind the wheel arch lining. When they are deployed during a side collision they provide potential protection for the chest area of the rear-seat passengers.

They are triggered when the central control unit and the side satellite sensors register acceleration or deceleration forces acting on the vehicle in excess of a certain threshold. The sidebags deploy at chest height between the vehicle side and the occupant.


In the event of a sufficiently severe side impact, the windowbag deploys to cover the side windows and reduce the risk of a collision between the passenger’s head and the side of the vehicle or of objects penetrating the vehicle interior. The windowbags are inflated at the same time as the sidebags (combined thorax/pelvisbags), as a rule on the side of the vehicle absorbing the side impact.

Once deployed, the windowbag covers the side panes between the A and C-pillars like a curtain. The window airbag covers a large part of the side when deployed.

The window airbag provides the following advantages:

  • Protection potential for the head in a side impact
  • Technical design and large volume provide excellent protection for occupants of all sizes
  • The deployment between A and C-pillar also protects rear passengers in the outside seats
  • Reduces head movement in the event of a direct collision
  • Reduces the intrusion of splinters and other objects

Phase 4: after an accident

To reduce consequential damage after an accident and support the work of the rescue services, a number of different actions are initiated, depending on the type and severity of the accident. Assisting emergency services after an accident is an important part of the safety philosophy of Mercedes-Benz.

  • Best possible protection: the engine can be turned off automatically and the fuel supply can be cut off.
  • Eye-catching lighting: hazard and emergency interior lights can activate automatically to lower the risk of accidents and help locate the car.
  • Making escape easier: the door locking mechanism can be automatically released.
  • Helpful connection: in the event of an accident or breakdown, automatic contact with an emergency centre can be established via the Mercedes-Benz emergency call system (part of the COMAND Online multimedia system) (in conjunction with a connected mobile phone)

[1] Only available in conjunction with 7G-DCT dual clutch transmission