“And ye shall be holy men unto me: neither shall ye eat any flesh that is torn of beasts in the field; ye shall cast it to the dogs.”
You are driving along the highway when you see a deer that was recently killed on the road ahead. You think, "What a waste! Why didn't they take it home?"
Road kill can be considered to be "flesh that is torn of beasts in the field".
Granted, the "beast" was a car; but the premise is the same.
Now days, you are more apt to find fresh road kill than fresh meat lying around on trails through the woods. However, even if you do, the verse still stands.
Just pull it off the road and leave it for other animals to pick from. It's ground meat can be processed and used as dog food if the dead animal is found fresh enough.
Oh, and don't touch the carcass with your bare hands. (Leviticus 11)