Assistance and safety systems

The optional high-tech assistance systems that Audi offers for the S8 make driving even easier, more relaxing and more composed. Their tight networking among themselves makes them particularly powerful. The Audi pre sense safety system is available in the standard version and three extended versions.

The central assistance system is Audi adaptive cruise control with stop&go function, a radar-assisted distance control system. Using two radar sensors that cover a wedge-shaped, 40 degree field 250 meters (820.21 ft) long, it controls the speed and the distance to the car ahead at speeds between 0 and 250 km/h (155.34 mph). It accelerates and brakes autonomously within certain limits, with maximum deceleration limited to 4 meters/s2.

The driver can set the time interval to the vehicle ahead in four steps and also specify one of three levels for the control dynamics.

When creeping along in traffic or in the city, ACC stop&go brings the large sedan to a stop with no input from the driver. If the stop is brief, the S8 automatically resumes moving again; after a longer stop the driver must tap the accelerator or the cruise control lever.

The adaptive cruise control with stop&go function uses the predictive route data from the MMI navigation plus system, and works closely with the other assistance systems. It uses the data from as many as 27 control units to continuously analyze the vehicle’s surroundings. Thanks to this high volume of information, it can also provide predictive support even in complex situations, reacting very similarly to a skilled driver.

The lane change assistant Audi side assist activates at speeds above 30 km/h (18.64 mph). Two radar sensors in the rear monitor events behind the S8 to a distance of about 70 meters (230 ft). If a critical situation arises because another car is cruising in the blind spot or approaching quickly, a yellow LED indicator lights up in the frame of the side mirror.

If the driver nonetheless activates the turn signal to change lanes, the indicator becomes brighter and begins to flash quickly – a signal that is hard to miss.

At above roughly 65 km/h (40.39 mph), Audi lane assist issues a warning if the driver is about to leave the lane inadvertently. A camera in front of the interior mirror monitors the road to distance of 60 meters (196.85 ft), and software detects the lane markings. If the S8 approaches a lane marking without indicating, Audi lane assist warns the driver by vibrating the steering wheel. The intensity and timing of the vibration can be set in three stages.

The images from the camera also benefit another assistance system: The speed limit display shows the current speed limit in the instrument cluster. In addition to speed limit signs, the system also recognizes digital speed limit displays and pictogram-based supplemental signs.

The software compares this information against additional data, such as that from the MMI navigation plus, and also draws on additional information from the vehicle, such as whether the windshield wipers are on and the current time.

An indicator recommending breaks is available for the first time ever in the S8. The system uses a variety of parameters such as steering motions to detect symptoms of fatigue and warns the driver via a display in the driver information system.

Greater foresight in the dark: the night vision assistant
Another high-end system in the new Audi S8 is the night vision assistant with highlighting of detected pedestrians. Its far infrared camera reacts to the heat emitted from objects. A computer converts the information from the camera into black and white images and shows them on the driver information system’s large display.

While the cooler surroundings appear dark, animals and people appear strikingly bright. The image-processing software detects people up to 100 meters away and highlights them with yellow markings on the display. If the computer assumes a hazardous situation, the person is marked red and a warning gong sounds.

With its 24 degree angle of aperture, the far infrared camera can look ahead up to 300 meters (984 ft), far beyond the high beam range. A window protects it against stone chipping; it is heated in cold weather and cleaned when dirty. Like every assistance system, the night vision assistant also works within certain system limitations.

Audi offers a variety of parking systems in the S8. The parking system plus uses eight ultrasonic sensors to indicate the distance acoustically and graphically on the large onboard display. The parking system plus with reversing camera uses an extremely light-sensitive camera that shows a wide area. The images generated by this camera are processed to remove distortion and displayed on the monitor. Guidelines and fields show the driver the car’s projected path.

The top version in the lineup is the parking system plus with 360° camera. Four small cameras – in the single-frame grille, in the rear and in the housings of the side mirrors – record images of the S8’s immediate surroundings and a computer stitches them together. The driver can call up a variety of views on the onboard monitor, including a top-down view. For narrow exits, there are special views that show the area in front of and behind the sedan and also allow a look at cross-traffic.

The safety system Audi pre sense basic is standard in the Audi S8. If the ESP stabilization program indicates a critical situation, such as skidding or maximum braking, its control unit intervenes. Depending on the situation, it activates the hazard warning lights and closes the side windows and the sunroof; it also partly or fully tensions the front seat belts. Small electric motors trigger this process, which is reversible; if the situation is averted without an accident, the belts are released again.

Protection against colliding with the vehicle ahead: Audi pre sense front
The first extended version of the system is called Audi pre sense front. It is permanently linked to the radar-based cruise control ACC with stop&go function. The system protects against colliding with a moving vehicle to the front, warning the driver in three stages. If the sedan is approaching a slower-moving car ahead, a warning gong sounds while a red signal lights up in the display.

Parallel to this, the brake system is prefilled and the air springs and dampers of the suspension are set to hard. The warning is intended to persuade the driver to apply the brakes or take evasive action, which is often the better choice.

If the driver remains passive, the acute warning – a warning jolt produced by the rapid generation of pressure in the brake system – is issued in stage 2. The seatbelts are lightly tensioned at the same time. If the driver now depresses the pedal, the hydraulic brake assist system handles precise braking relative to the preceding vehicle. The fact that the system is already prefilled saves between 0.1 to 0.2 seconds, or more than seven meters (22.97 ft) at a speed of 130 km/h (80.78 mph).

Should the driver also ignore the warning jolt, the third stage is activated – partial braking that initially slows the S8 at a rate of 3 m/s2. The windows and sunroof are closed, and the hazard warning lights are activated.

If the sedan is equipped with the top-of-the-range safety system – Audi pre sense plus, which is part of the assistance package – a fourth stage follows, if necessary. The system now increases deceleration to 5 m/s² and pulls the belts tight. This is followed by a final braking phase with full brake application. It begins about half a second before impact – at this point there is no longer any time for evasive action. The force of the collision and its consequences are greatly reduced, for by impact the S8 has cut its speed by as much as 40 km/h (24.85 mph).

Audi side assist is bundled with Audi pre sense rear in the S8. The system mitigates the consequences of a rear-end collision; it closes the windows and sunroof and tightens the belts.

The top of the seat back and the front headrests move into a position that reduces the risk of whiplash, and the pneumatic seat bolsters are filled with air to hold the passengers securely.

The equipment, data and prices specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.