Ironically, the UK already does quite a bit better than the USA in pedestrian safety, despite having much more history of existing built environment. Or actual

Ironically, the UK already does quite a bit better than the USA in pedestrian safety, despite having much more history of existing built environment. Or actually, it's perhaps not ironic, it's perhaps because of the limitations of the existing built environment in the UK, which prevented doing what has been done in many parts of the USA -- optimize for car speed over pedestrian safety.