Limitations for assistance at risk of collision

Assistance at risk of collision1 has certain limitations that a driver should be aware of.

Limitations for brake assistance

Extra equipment

Low-hanging objects, e.g. a flag/pennant for projecting load, or accessories such as auxiliary lamps and bull bars that are higher than the car bonnet limit the function since they may obstruct the camera or radar unit.


On slippery road surfaces the braking distance is extended, which may reduce the capacity of the function to avoid a collision. In such situations, the anti-lock brakes and the stability control ESC2 are designed to give the best possible braking force with maintained stability.

Low speed

The function is not activated at very low speeds – below 4 km/h (3 mph) – and the system therefore does not intervene in situations where your car is approaching a vehicle ahead very slowly, e.g. when parking.

Active driver

Driver commands are always prioritised. The function does not intervene in situations where the driver is steering and accelerating in a decisive manner, even if a collision is unavoidable. Active and aware driving behaviour can therefore delay a collision warning and intervention in order to minimise unnecessary warnings.

Limitations for steering assistance

In certain situations the function may have limited functionality and fail to intervene in the following cases, for example:
  • for small vehicles, such as motorcycles
  • if the majority of the car has moved into the adjacent lane
  • on roads/in lanes with unclear or non-existent lane markings
  • outside the speed range 60-140 km/h (37-87 mph)
  • steering assistance for evasive manoeuvres: outside the speed range 50–100 km/h (30–62 mph)
  • as the steering servo for speed-dependent steering wheel resistance is working at reduced power – e.g. when cooling due to overheating.
Other demanding situations can include:
  • road works
  • winter road conditions
  • narrow roads
  • poor road surface
  • a very “sporty” driving style
  • poor weather with reduced visibility.

In these demanding situations, the function may have difficulty helping the driver correctly.

Important warnings


Driver supports only warn of obstacles which their radar unit has detected – hence a warning may not be given, or it may be given with a certain delay.
  • Never wait for a warning or intervention. Apply the brakes when the situation requires.


  • Automatic braking can prevent a collision or reduce collision speed, but to ensure full brake performance the driver should always depress the brake pedal – even when the car brakes automatically.
  • The warning and steering assistance are only activated if there is a high risk of collision – you must therefore never wait for a collision warning or for the function to intervene.
  • The function does not activate any automatic brake interventions in the event of heavy acceleration.


  • Warnings and brake interventions could be implemented late or not at all if a traffic situation or external influences mean that the camera and radar units cannot detect pedestrians, cyclists, large animals or vehicles correctly.
  • For vehicles to be detected at night, their headlamps and rear lamp cluster must be switched on and shining clearly.
  • Warnings for stationary and slow-moving vehicles, as well as large animals, may be disengaged due to darkness or poor visibility.
  • Warnings and brake interventions for pedestrians and cyclists are deactivated at vehicle speeds exceeding 80 km/h (50 mph).
  • The system can provide effective warnings and brake interventions as long as the relative speed is below 50 km/h (30 mph).
  • For stationary or slow-moving vehicles, warnings and brake interventions are effective at vehicle speeds up to 70 km/h (43 mph).
  • Speed reduction for large animals is less than 15 km/h (9 mph) and can be achieved at vehicle speeds above 70 km/h (43 mph). The warning and brake intervention for large animals is less effective at lower speeds.
  • Do not place, stick or mount anything on the outside or inside of the windscreen in front of or around the camera unit – this can interfere with camera-dependent functions.
  • Objects, snow, ice or dirt in the area of the camera and radar units may reduce their functionality, fully deactivate them or give incorrect function response.


This function uses the car's camera and radar units, which have certain general limitations.


Maintenance of driver support components must only be performed at a workshop – an authorised Volvo workshop is recommended.
  1. 1 Collision Avoidance
  2. 2 Electronic Stability Control