Planned roads are not objects that can be seen on the ground, so the source of the data must be specified each time. This can be the source=* tag on the object or in the changeset. Note that generally, OpenStreetMap encourages information to be verifiable on the ground. Proposed features that are not visible on the ground should therefore only be mapped in exceptional cases and after a discussion with the relevant OSM community, lest they might be deleted for lack of verifiability