For biking and walking, could accepting data from Strava users (or other places that let you download GPS tracks), let you infer where there are sidewalks and good bike routes?
Eg if you have 20 GPS traces in an area and they all turn at one point, that’s a good place to turn. Or you can assume something has a sidewalk if many people have walked there?
Eg if you have 20 GPS traces in an area and they all turn at one point, that’s a good place to turn. Or you can assume something has a sidewalk if many people have walked there?