Under HUD’s definition, a car is not a place suitable for human habitation, so that’s clearly someone who’s homeless. An RV dweller may be considered homeless if they are in an “unstable” living situation (moved twice or more within the past 60 days), or if the RV is in such disrepair to not be suitable for habitation.

Edit: see https://www.urban-initiatives.org/reports/are-all-persons-sl...