iirc, one of those Alaska shows on discovery showed that when a large animal is hit on the road, not only is it legal to process the animal into food, but it's the law. You can't hit a moose and leave it on the side of the road and drive away (although, you'll be lucky if you're not being taken away in an ambulance after hitting a moose). This may only be true in rural areas of alaska, not in population centers like Juno/Anchorage/etc.
In contrast, I am not sure but I think in some other areas, it is illegal to keep roadkill, such as a deer, unless you call the police or local game warden's office to issue you a permit for it. I think they don't want people intentionally "hunting" for deer in the manner... of course you could still do it and claim it was an accident, but I'd imagine if you became a "regular roadkill killer" you might raise a few eyebrows.
Again, I'm not 100% sure on these statements, but seem to recall those are laws...
One thing I've always wondered about is what you're supposed to do if you hit and severely injure but do not kill an animal, such as a deer. An armadillo, opossum, skunk, racoon, etc, you're most likely not even going to pull over... but I'd feel kind of bad if I hit a deer and it's laying there suffering. I've always thought if that ever happens to me, I'd call the police and hopefully they could shoot it... Anyone know?