TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 383: Changeable Message Sign (CMS) Displays During Non-Incident, Non-Roadwork Periods explores the use of CMSs to convey messages on non-recurrent, environmental, special event traffic, and other special problems. Report located at https://www.trb.org/news/blurb_detail.asp?id=9710.