Slowing cars down is huge. First of all, probability of someone dying when a driver hits a person dips below 5% right around 20mph. At that point you already in

Slowing cars down is huge. First of all, probability of someone dying when a driver hits a person dips below 5% right around 20mph. At that point you already invite life back onto the street. Then once you have it there, drivers learn that they can't be distracted. Drivers should not feel comfortable when driving in urban environments. That's not say you shouldn't have good old-fashioned car sewers, but the dearth of accesses should make it abundantly clear that those places are just car-movers, not places where economic activity happens.