Gah! Your second message didn’t appear until after I posted…

Personally I think that in most cases it’s better to just leave it untagged, but wouldn’t bother to remove the foot=yes tag unless there are sidewalks mapped separately (that don’t have any un-mapped crossings/segments etc that could screw up routing).

To be clear, I am agreeing with you that the foot=yes tags can (and probably should) be removed from Van Ness. I only added it because pedestrian routers were giving screwy results without it, and it doesn’t serve a practical purpose anymore.

There’s some ambiguity in the actual California and SF laws (which are slightly different), but neither actually prohibits pedestrians from walking within the roadway, as long as they stay out of the way of traffic and don’t walk in the bike lane.

Under SF law ( https://codelibrary.amlegal.com/codes/san_francisco/latest/sf_transportation/0-0-0-387 ) people can theoretically cross anywhere as long as they walk in a straight perpendicular line, except in the “Downtown Core”. Under CA law ( https://leginfo.legislature.ca.gov/faces/codes_displayText.xhtml?lawCode=VEH&division=11.&title=&part=&chapter=5.&article= ) jaywalking is only prohibited between “adjacent intersections controlled by traffic control signal devices or by police officers”. I would assume that would apply to almost all of Van Ness, unless intersections with alleys are legally considered intersections.

(I am probably the person who originally added the foot=yes tags years ago.)

For a long time Van Ness was tagged as highway=trunk (because it’s US 101), and some routers treat that as foot=no without an explicit access tag. It’s probably not necessary now that it’s been downgraded.

In general the way is supposed to represent the entire street at least on some level. It is of course legal to walk down Van Ness since it’s a public street. It’s even legal (and sometimes necessary) to walk in the roadway in certain situations, so I wouldn’t add a foot=no tag.

I originally added the sidewalk=* tags to Van Ness (and about one third(?) of the streets in SF) several year ago. The separately-drawn sidewalks are fairly new and I’m not sure if the people who mapped them were even aware that the sidewalk=* tags existed, so now there are a ton of double-mapped sidewalks around. I’m not sure what the best way to deal with that is.

I’ve tried to clean a lot of these up in the SF Bay Area and Boston. What I’ve observed is that in older parts of cities, they tend to be fairly well-known neighborhoods that can be easily re-tagged as place=neighbourhood or suburb, but the rest really need someone who is familiar with the area to fix them. Some are really obscure and wouldn’t be fixable by someone from outside the immediate neighborhood.

For housing projects and trailer parks I’ve created a named landuse=residential polygon. Some of them are unincorporated communities that are big enough to be tagged as a village or town. A lot of them are old names for places that are already on the map, or names of towns that have been absorbed by other places and disappeared completely from modern use. A few of them were actually buildings. One of them was a trailhead. I’ve only seen one that actually was a hamlet.

In California many (maybe most) look like old names given to locations along railroad lines by the railroads in the 19th century, and those are harder to deal with. Some still exist in some form (usually towns, neighborhoods, or train stations), some were towns or stations that no longer exist, some only ever existed in theory.