I noticed that my friend's pioneer deck has an option that controls the volume when he's driving. The volume automatically increase/decrease when he's driving. Do alpine have that option? BTW, I have an Alpine CDA 105

 

The option you are referring to is basically to battle 'road noise' it adjust the volume accordingly, i believe some kenwood models had this too, but i am not aware if the alpine offered this or not, if so it is a recent thing (last 2-3 years), usually alpine in the past offered more quality as opposed to bells and whistles.
personally i would probably find the auto adjustment annoying.

 

I have owned few Alpines and never seen this feature.. Which model does your friend have?

 

alpine does not offer that option. Main reason is, that it is stupid.