Safety: flashing brake lights warn following traffic
The adaptive brake light introduces technology from the luxury class into the compact segment, which therefore benefits from a further accident prevention system as a standard feature. Under emergency braking from a speed exceeding 50 km/h, the brake lights flash rapidly to warn following traffic, enabling drivers to respond quicker and prevent a collision.
Flashing brake lights are the result of extensive practical research covering the braking behaviour of drivers. Mercedes engineers found that the braking responses of drivers are on average 0.2 seconds faster in emergency braking situations if a flashing red warning is given in place of conventional brake lights. The stopping distance can be reduced by around 4.40 metres from a speed of 80 km/h, and even by around 5.50 metres from a speed of 100 km/h. If the A‑Class is brought to a rapid stop from a speed exceeding 70 km/h, the hazard warning system is switched on in addition to the flashing brake lights.
The A-Class sets standards in this market segment where occupant protection is concerned, with two-stage front airbags, belt tensioners in the front and for the outer rear seats, belt force limiters, active front head restraints and head/thorax sidebags. Mercedes-Benz has now added to this extensive safety technology with crash-responsive emergency lighting for the interior. This is switched on automatically following an accident of a defined severity, providing the occupants with better orientation and facilitating the work of the emergency services.
Parking assist: ultrasound and electric steering for easier parking
When finding and reversing into a parking space, drivers of the A-Class will in future be aided by an active parking assist feature which is available on request for all model variants. Using side-mounted ultrasonic sensors, this system identifies suitable parking spaces on both sides of the road in passing, then informs the driver by means of a display. The sensors are active up to a speed of 35 km/h, and monitor the area to the left and right of the A-Class. They measure the length and depth of possible parking spaces, indicating that the search is in progress with a " P " in the instrument cluster.
Once a suitable parking space has been found, an arrow appears in the display to inform the driver on which side of the road the parking space is located. If he engages reverse gear, acknowledges the display message and accelerates, active parking assist takes over the steering and automatically manoeuvres the car into the parking space. The driver only needs to accelerate and operate the brakes; the ultrasonic sensors of the PARKTRONIC system assist him in this by keeping him informed about the distance to the vehicle in front of and behind the A-Class.
Active parking assist uses a total of ten ultrasonic sensors in the front and rear bumpers, as well as an electronic control unit which processes the sensor signals and calculates the best possible entry path into the parking space. This information is fed to the electromechanical power steering, whose electric motor performs the necessary steering movements of its own accord. The parking space only needs to be 1.30 metres longer than the A-Class for this automatic parking procedure to take place – an indication of the great precision of this technology. Thanks to its very compact dimensions, a parking space with a length of just 5.18 metres or so is sufficient; there is currently no other car able to park automatically in such a small space.
Mercedes engineers have also added a new function to a well-proven support system: the Electronic Stability Program (ESP®) of the A-Class now has an automatic hill-holder function which prevents the car from rolling backwards when the driver changes from the brake pedal to the accelerator when moving off on an uphill gradient. In these situations ESP® maintains the brake pressure for a short time, so that the driver can move off smoothly.
Audio: new units offer Bluetooth, a colour display and Europe-wide navigation
Like all the new 2008 Mercedes models, the A-Class is available with further improved information, communication, navigation and entertainment systems – in other words infotainment. There is a choice of four optional head units:
Audio 5, Audio 20, Audio 50 APS and COMAND APS. From Audio 20 these incorporate a radio with twin tuner, colour display, a Bluetooth interface for a mobile phone, a telephone keypad, a CD-player, automatic volume adjustment and a connection for external audio units in the glove compartment. Audio 50 APS is also equipped with a Europe-wide DVD navigation system and a DVD drive, while the top-of-the-range COMAND APS features HDD navigation, a music register, a slot for SD memory cards and voice control. The LINGUATRONIC system operates the telephone, audio and navigation system by convenient whole-word commands. The driver need no longer spell out his wishes, but simply needs to say what he wants when entering a destination, selecting a radio station or accessing an entry in the telephone directory.
Interface: the "iPod" can be operated via the keys on the steering wheel
More scope for mobile musical enjoyment is provided by a newly developed, interactive media interface, which is able to connect an MP3-player, USBstick or other external audio unit with the infotainment system of the car. This means that external audio units can be conveniently operated using the keys on the multifunction steering wheel, while the titles of music tracks are shown in the instrument cluster and on the colour display in the centre console. While the portable audio unit is connected to the car via the media interface, its battery is charged. Connection of an iPod or similar requires a suitable cable which is available from the Mercedes-Benz accessories range.
The award-winning "Logic 7®"surround sound system, which celebrated its world premiere in the S-Class, is also available for the A-Class. The system has an output of 450 Watts and features twelve loudspeakers (Coupé: ten).