It is a lot of work getting a deer off the highway. Only real risk is the heat. Get it early and butcher it fast before the meat can spoil. Do it right and it is a great thing. Jerky, steaks, ground meat has never been so easy. I've spent hours and hours, day after day hunting and never see a thing I can shoot, and I'm usually way way far off from my vehicle. Compared to hunting, harvesting highway kills is the best way to go.
I drive past a carcass or two every day. There seems to be a glut of roadkill in Kansas City, and no one seems to be harvesting. There are more dead deer littering the highways than raccoons or squirrels, and I don't think I've seen a dead oppossum this year. I have seen more live deer this month than I have cattle & horses combined. And those critters at least stay inside the fence where they are put.
So far as I know, the police & sheriffs departments make no effort to coordinate the collection of road kill. They get pushed off to the side or pounded into the pavement until the dead animal dept picks them up for disposal.
As far as hunting goes? If I were of a mind to, I could harvest deer from my mother-in-laws back porch, damn near any morning. Last year I spotted a buck, doe, and fawn settling into my mother's back yard, bedding down by the back fence. He was a nice 6-8 pointer, too. That was in solid suburbia, with a 5 lane busy street only 100' away, and hardly an undeveloped property for miles.
If you want deer, Kansas City's got them. Oops!
No hunting is permitted within city limits.
Some folks in the rural areas do it anyway.