Audi offers an attractive portfolio of assistance systems in the A4 family. Four of them are available as options. The driver information system with break recommendation comes standard in all models with more than 88 kW of power. It can contribute a great deal towards road safety, since about one fourth of all traffic accidents can be attributed to driver fatigue.
The driver information system with break recommendation continuously observes the driver’s steering movements and activation of the gearshift and gas pedal. It thus computes and stores a profile unique to the driver. If the system’s control unit detects that the driver is deviating from their profile – the steering wheel is hardly being used, for instance – visual and audible alarms are triggered. In operation at speeds above 65 km/h (40 mph), the system can be deactivated – like all Audi assistance systems – at any time.
With new capabilities: adaptive cruise control
The adaptive cruise control (ACC) is the most complex of the optional driver assistance systems available in the model family. At speeds between 30 and 200 km/h (18.64 and 124.27 mph), the radar-based system maintains a specified interval between the A4 and the vehicle ahead by accelerating and braking autonomously within certain limits. The driver can switch between four settings to specify the extent to which the system should be comfortable or sporty; following distance can likewise be set to one of four levels.
ACC also features the integrated Audi braking guard. The system warns the driver if the radar sensor of the A4 detects an impending collision with the vehicle ahead. The intensity of the warning varies with the danger of the situation. A gong-like chime and a red signal lamp on the driver information system’s display constitute the first level of warning. At the same time, the brake system is preemptively refilled and the brake pads are positioned close to the discs. If the driver now steps on the pedal, braking is practically instantaneous.
If the driver does not react, however, the second warning level causes the system to briefly brake the vehicle – an attention-grabbing jolt for the driver. If the driver now brakes but does not sufficiently depress the brake pedal, the hydraulic brake assist will boost the braking force as merited by the given situation. If the driver fails to react at all, the system partially brakes on its own to decelerate the A4 by approximately 3 m/s2.
In an emergency at speeds below 30 km/h (18.64 mph), the Audi A4 will apply the brakes with full power – regardless of whether the vehicle ahead is stationary or in motion. At speeds below 20 km/h (12.43 mph), this full braking generally prevents the accident altogether. In other cases, it greatly reduces the impact speed, thus reducing the severity of the accident.
The optional Audi side assist helps the driver when changing lanes. At speeds of 30 km/h (18.64 mph) and above, radar sensors at the rear of the car monitor what goes on behind the A4.
If another vehicle enters the blind spot or rapidly approaches from the rear, a yellow LED indicator in the outside mirror’s housing will light up. If the driver nevertheless activates their turn signal, the indicator will brighten and flash rapidly – it is practically impossible to overlook!
New to the A4 model series is Audi active lane assist, which goes into operation at 65 km/h (40.39 mph). A small video camera in the interior mirror detects the lane markings on the road surface. If the A4 approaches a lane marking without the turn signal having been activated, the system gently intervenes in the new electromechanical steering to coax the driver to remain in their lane. Drivers use the MMI operating system to specify how quickly this assistance system should intervene as well as whether this should be accompanied by vibration of the steering wheel.
Audi offers a choice of three different solutions for easy parking. The top version is the parking system plus with reversing camera. It employs a fisheye lens to film the area behind the car. Images are first corrected by software and then displayed on the MMI monitor; guidance lines and fields help the driver to steer.
The equipment and data specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.