It filters to ways with the "highway" attribute, which has possible values including "footway", "bridleway", "steps", and "corridor" in addition to the ones you'd expect with the American definition of the word ("motorway", etc)

https://wiki.openstreetmap.org/wiki/Key:highway?uselang=en

https://github.com/anvaka/city-roads/blob/08a21bce05ad2b08d4...