It's prohibitively expensive, better would be to sacrifice some city corridors as pedestrian only. Cars don't need to be in the city centre on every street. Mo

It's prohibitively expensive, better would be to sacrifice some city corridors as pedestrian only. Cars don't need to be in the city centre on every street. Most pedestrian friendly streets that do mix in cars actually do the opposite to grade separation, slow down the cars a lot and make it clear that they are in a pedestrian space by removing demarcation between cars and people,which changes behavior.