Collision warning system* - function

"Collision Warning with Auto Brake and Cyclist and Pedestrian Detection" is an aid to assist the driver when there is a risk of colliding with a pedestrian, bicycle or vehicle in front that are stationary or moving in the same direction.
P4-1220-Collision Warning - Komponentplacering Sedan
Function overview1.
  1. Ikon röd cirkel 1Audio-visual warning signal in the event of a collision risk.
  2. Ikon röd cirkel 2Radar sensor2
  3. Ikon röd cirkel 3Camera sensor

Collision Warning with Auto Brake executes three steps in the following order:

  1. Collision warning
  2. Brake support3
  3. Auto Brake3

The collision warning system and City Safety™ complement each other.

1 - Collision warning

The driver is first warned of a potentially imminent collision.

The collision warning system detects pedestrians, stationary vehicles as well as vehicles driving in the same direction in front of the car.

If there is a risk of collision with a pedestrian or a vehicle then the driver's attention is attracted with a flashing red warning signal (1) and an acoustic signal.

2 - Brake support2

If the risk of collision has increased further after the collision warning then the brake support is activated.

This means that the brake system is prepared for rapid braking by applying the brakes lightly, which may feel like a slight jolt.

If the brake pedal is depressed sufficiently quickly then full brake function is implemented.

Brake support also reinforces the driver's braking if the system considers that the braking is not sufficient to avoid a collision.

3 - Auto Brake2

The automatic brake function is activated last.

If in this situation the driver has not yet started to take evasive action and the risk of collision is imminent then the automatic braking function is deployed - this takes place irrespective of whether or not the driver brakes. Braking then takes place with full brake force in order to reduce collision speed, or with limited brake force if it is sufficient to avoid a collision. For cyclists, the warning and full brake intervention may come very late or simultaneously.


The collision warning system does not engage in all driving situations or traffic, weather or road conditions. The collision warning system does not react to vehicles or cyclists driving in another direction to the car or to animals.

Warning only activated in the event of a high risk for collision. This section "Function" and the section "Limitations" inform about limitations that the driver must be aware of before using the Collision Warning system with Auto Brake.

Warnings and brake interventions for pedestrians and cyclists are deactivated at a vehicle speed exceeding 80 km/h.

Warnings and brake interventions for pedestrians and cyclists do not work in darkness and tunnels - not even when streetlights are lit.

The auto-brake function can prevent a collision or reduce collision speed. To ensure full brake performance, the driver should always depress the brake pedal - even when the car auto-brakes.

Never wait for a collision warning. The driver is always responsible that the correct distance and speed are maintained - even when the collision warning system with auto-brake is used.

  1. * Option/accessory.
  2. 1 NOTE: The illustration is schematic - details may vary depending on car model.
  3. 2 With system Level 2 only.
  4. 3 With system Level 2 only.