Not that simple. I have a hunch that network effects play huge role too. Chances of london having two orders of magnitude car/pedestrian interactions more than

Not that simple. I have a hunch that network effects play huge role too. Chances of london having two orders of magnitude car/pedestrian interactions more than also are not low. So the chances of fatality per interaction could be comparable. But you have shitload more of them in london since everything is bigger there so you clock more miles.