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Assistance at risk of collision1

Assistance at risk of collision2 can assist the driver to avoid a collision via a warning, automatic braking and steering assistance.
PS2-2007-City Safety audio-visual warning and radar sensor
Function overview
  1. PS-Icon circle 1Light signal in the event of a risk of collision
  2. PS-Icon circle 2Warning signal in the event of a risk of collision
  3. PS-Icon circle 3Distance measurement with the camera unit and radar unit

The driver or passengers are not normally aware of the function - it only intervenes in a situation where a collision is immediately imminent.

The function can help the driver to avoid a collision when driving in queues, e.g. when changes in the traffic ahead, combined with a lapse in attention, could lead to an incident. The function then activates a short, sharp braking procedure, normally stopping the car just behind the vehicle ahead.

The function cannot be deactivated but is always activated. However, system sensitivity can be selected.

Subfunctions

Assistance at risk of collision can perform the following functions if necessary:
  • Collision warning
  • Assisted braking
  • Automatic braking
  • Steering assistance

Step 1 – Collision warning

In the event of a risk of collision with a pedestrian, cyclist or vehicle, the driver's attention is alerted by means of a visual, acoustic and brake pulse warning. At lower speeds or with heavy braking or acceleration there will be no brake pulse warning as the intensity of the brake pulse varies with the speed of the car.

Step 2 – Assisted braking

Assisted braking reinforces the driver's braking action if the system considers that the braking is not sufficient to avoid a collision.

Step 3 – Automatic braking

If the driver has not started to take evasive action and the risk of collision is imminent then the automatic braking function is deployed - this takes place regardless of whether 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.

The seatbelt tensioner can be activated in connection with the engagement of the automatic brake function.

The function is designed to be activated as late as possible in order to avoid unnecessary intervention. Automatic braking takes place only after or at the same time as the collision warning.

When automatic braking has prevented a collision with a stationary object, the car remains stationary in anticipation of positive action by the driver. If the car has been braked to avoid collision with a slower vehicle in front, its speed is reduced to match that of the vehicle in front.

The driver can always interrupt a braking intervention by firmly depressing the accelerator pedal.

When the function is activated and brakes, the brake lights are switched on. The driver display shows a text message to advise that the function is or has been active.

 Warning

The function must not be used by the driver to change his/her driving style - the driver must not rely on function alone and allow it to do the braking.

Steering assistance

The function can help the driver reduce the risk of the car leaving its lane unintentionally or colliding with another vehicle or obstacle by actively steering the car back into its lane or swerving. Steering assistance is not part of a sequence but can be applied regardless of when the other steps occur.

After automatic engagement, the driver display indicates that this has occurred via a text message.

 Note

It is always the driver who decides how much the car should steer – the car can never take command.

 Warning

  • The function is supplementary driver support intended to facilitate driving and make it safer – it cannot handle all situations in all traffic, weather and road conditions.
  • The driver is advised to read all sections in the Manual that relate to this function to learn about factors such as its limitations and what the driver should be aware of before using the system.
  • Driver support functions are not a substitute for the driver's attention and judgement. The driver is always responsible for ensuring the car is driven in a safe manner, at the appropriate speed, with an appropriate distance to other vehicles, and in accordance with current traffic rules and regulations.
  1. 1 The function is not available in all markets.
  2. 2 Collision Avoidance