It's easy to find US cities with plenty of sidewalks that are hideously unwalkable, as well as many streets in Japan with no sidewalks that are still highly walkable.
Unless there are separate streets for pedestrians (which is basically non existent in US most of the time), not sure how you can have any city walkable without sidewalks.
Mainly by making motorists responsible for killing pedestrians. Instead, in America you mostly don't even get fined for running over a pedestrian, as "it's just an unfortunate accident", even when you have chosen to purchase a vehicle that makes it harder to safely navigate around pedestrians.
Consider: Do other countries even have the concept of "Jaywalking", which was explicitly an attempt by vehicle manufacturers to blame pedestrian deaths on pedestrians.
I'm not talking about all streets in a given city obviously. Specifically in Japan, narrow streets with no sidewalks are omnipresent in neighborhoods, and they're still far more walkable than a typical US neighborhood street with sidewalks.
Yes, that definitely helps. It's a chicken and egg situation though. If the roads are wide then of course many will buy huge cars, and then urban planners feel they have to accommodate those with wider roads, etc.
