Comment by Teever
I think you're kind of looking at this the wrong way.
As I understand it 'vision zero' type programs are often an aspirational goal, and they implicitly recognize the near impossibility of reaching the goal, but that near impossibility doesn't make the goal undesirable or not worth striving for.
If you set such a goal you start to analyze the systems involved which cause accidents and deaths in a different way and you seek change them on a fundamental level to significantly reduce if not outright eliminate the possibility of certain categories of accidents entirely.
So instead of doing moderately effective but ultimately fleeting stuff like cracking down on speeders and drunk drivers through police action you redesign the infrastructure so that it becomes much harder for a car to physically strike pedestrians through traffic calming[0] measures, creating physically separate pedestrian and bike infrastructure so that cars just don't come in contact with people, or implement mass transit so that you simple decrease the number of drivers on the road and again physically separate them from automobiles to eliminate the possibility that they're involved in car accidents.
In doing so you not only reduce the number of accidents that injure and maim people but you induce them to be more physically active and therefore healthier so that they're able to better car accidents, slips and falls, and illnesses which ends up paying for the infrastructure improvements over the long run.
This is so much better than the alternative where speeders consistently speed and kill pedestrians in an unmarked cross walk so we decide to play whack-a-mole by increasing the police budget for photo radar for a while until the public forgets that this particular street is dangerous to cross on foot.