I one collected a road-kill deer, very fresh, and obtained a permit for it (possible in NJ). With the help of a friend, we cleaned, bled, and hanged the deer, then took it to a local meatpacker.
It was great meat: tender, and low in fat content. There is no reason that this should not be permitted. The roadkill must be obtained quickly, and handled well, though; so it is best if the consumer does his own.
Even better would be to allow certain game to be sold in restaurants. We need some control on the overpopulation of deer and Canada Geese, especially.
I hit a deer on the I-70 just outside of Kansas City, KS back in 1974. The highway patrolman who responded put it in his trunk...................