From OpenStreetMap Wiki
Are you planning to map each sidewalk as an explicit way or just adding tags to the main road network?
- In the latter case, please use the correct keys sidewalk:left/right:surface and sidewalk:left/right:width.
- If you plan to map them as explicit ways, please state that you will add connection nodes at the intersections.
-- Species 09:49, 15 July 2016 (UTC)