Even when the police and air ambulance helicopters land and takeoff on a road, the traffic has to be controlled i.e. stopped and a suitably sized operating space cleared. If on a dual carriageway or motorway, the traffic in both directions has to be stopped. Been there, done that.
So, if you think these would be allowed to fly from public roads in a random fashion, at least in UK, you're kidding yourself.
If you had one of these (and who didn't dream about having something like this, as a kid?), in practice it would be so expensive to buy and maintain, and so bad at being a car, that you'd want to fly it all the time. Then you'd be better off with a proper aircraft in the first place.
It's like owning a Reliant Robin of the road, and a Reliant Robin of the skies, but not as good as either.