Generally, the focus should be on moving people, not cars. The last couple of times I was in midtown Manhattan, the sidewalks were at crush level. People were spilling out into traffic to avoid being crushed because there just was no room on them. New York has big avenues. You could take away a lane of parking and/or traffic and widen the sidewalks. This won't happen, of course, because moving cars is the most important thing. But a hell of a lot more people were on the sidewalks than were in those cars.