This synthesis report will be of interest to state highway design engineers and structural engineers, as well as environmental and historic preservation personnel in transportation agencies. It will also be of interest to state historic preservation offices, federal historic preservation agencies, and engineering preservation consultants. It describes the current state of the practice and experience of state and local transportation agencies dealing with the preservation of historic bridges in their jurisdictions. Information for the synthesis was collected by surveying U.S. state and federal transportation agencies and by conducting a literature search. The synthesis is intended to complement NCHRP Synthesis 101, Historic Bridges--Criteria for Decision Making (1983), and draws on that work by reference. This report of the Transportation Research Board provides information on the policies, decision criteria (or models), and administrative practices used to determine which historic bridges to preserve and the specific preservation option to be employed with each. It also emphasizes the experience of highway agencies in administering these policies and practices, describes a number of successful examples, and identifies some unresolved issues. Several case studies are included to highlight the differences between the policies and practices of state transportation agencies and preservation agencies.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3284