I don't really understand why your score is 0 (at the time I looked) as I think that you are absolutely right.
Where I live, it has shown in multiple studies that the surrounding really has a great impact on the behavior of motorists.
To these nay-sayers I say: According to your logic, a totalitarian police state would make a perfectly safe society.
It all boils down to traffic psychology. A big portion of car drivers automatically want to up the speed when they are on a broad (and empty) road. I even want to go as far to say that some (local) governments deliberately create such roads while keeping the max. allowed speed limit low and fill the road with speed camera's. Not because of safety, but to milk the road as a cash cow. This is called 'enticement'.
To resolve these questions and keep it fair and safe for everyone, the traffic psychology should be addressed. By changing the infrastructure in such away to demotivate speeding or other reckless behavior by affecting traffic psychology. Of course, the few people that are still traffic hazards should also be fined. So the policing of the roads still remain. But adjusting the way a road is designed can help a lot.