To change the cruising speed

See also:

New Level of Comfort and Convenience in All Models
Standard comfort and available amenities are increased across the Subaru Legacy line for 2010. The base 2.5i model, for example, features standard steering wheel audio and cruise control buttons, ...

Adjustable level of each volume
...

Legacy
Your AWD vehicle is neither a conventional off-road vehicle nor an all terrain vehicle. It is a passenger car designed primarily for on-road use. The AWD feature gives it some limited off-road cap ...