Crossword clues for Interstate abbr. 3 lettersAnswerClueRTEInterstate (abbr.)HWYInterstate abbr.RRSSubjects of interstate regulation: Abbr.RTEInterstate sign: Abbr.HWYInterstate, e.g.: Abbr.RDSInterstates, e.g.: Abbr.DDEInterstate Highway System creator: Abbr.HWYInterstate road, for example: Abbr.HGWYInterstate: Abbr.RTESInterstates: Abbr.HWYSInterstates, e.g.: Abbr.