See also:

Changing the set speed
After a speed has been set, it can be increased or decreased by using the or buttons. Each time one of these buttons is pressed, the vehicle's speed changes by 5 mph (approximately 8 km/h). ...

Accessory installation
We strongly recommend that Volvo owners install only genuine, Volvo-approved accessories, and that accessory installations be performed only by a trained and qualified Volvo service technicia ...

Situations where ACC may not function optimally
WARNING The radar sensor has a limited field of vision. In some situations it may detect a vehicle later than expected or not detect other vehicles at all. If ACC is not functioning prop ...