I think we can learn some things from the way some French cities do things. Most days and most hours of the day, cars can drive on all streets, however, on weekends and some other times, in certain core commercial areas, only delivery vehicles are allowed and these streets become pedestrian-only. I'm okay with that. [as an aside, interestingly, people are in some areas, are allowed to park on the pavement (sidewalks) --which is a bit jarring at first].