This synthesis will be of interest to bridge designers, materials engineers, maintenance engineers, and others concerned with coating systems used to protect bridge steel from corrosion. Information is presented on the causes of steel corrosion and the types of surface preparation and coatings used to protect the steel. Steel bridges need some type of protective coating to keep them from corroding. This report of the Transportation Research Board explains the mechanisms of steel corrosion and how coatings protect the steel, discusses the need for and types of surface preparation, and describes twenty types of available coating systems under three general categories: inhibitive systems, zinc-rich (sacrificial) systems, and barrier systems.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3421