Roads often do make a big difference - if there are too many lanes it you end up with a block-sized, loud and dangerous chasm in the middle of what could be a bustling neighborhood.
I live in Tokyo and it’s dominated by streets that are literally barely wide enough to have two cars pass each other at <5mph, and I’ve come to love that.
IMO this still just comes down to density. Getting to a park just across a 3 lane divided highway isn’t a problem especially via skyway or underground tunnel. Walking 5 miles to that same park isn’t.
Narrow streets can significantly boost city density which then gets people out of their cars. One way streets make crossing traffic easier. But, if there’s nowhere to walk to then it’s all kind of pointless.
I kinda disagree. Highways are usually real barriers within cities. So much so that, if a city made the mistake of running highways through itself or along its waterfront, it's now worth it to spend billions burying the thing or building some kind of giant elevated park on top.
Not saying you’re wrong but in Tokyo most of the streets I mentioned have no sidewalk but just by the nature of being tiny they don’t need one - cars will pass at very slow speeds anyway. Agreed that it only matters if you can achieve high density, but part of achieving high density is designing for it, including not optimizing car traffic.
I live in Tokyo and it’s dominated by streets that are literally barely wide enough to have two cars pass each other at <5mph, and I’ve come to love that.