This synthesis report provides state-of-the-practice findings obtained from transportation agencies about commonly used expansion joint systems. It summarizes performance data for each system type, as well as contains examples of selection criteria and design guidelines. The report includes lessons learned for maximizing the service life of the joint systems and methods to determine if they are watertight. Bridge deck expansion joints facilitate longitudinal movement (translation) and small amounts of rotation, which occur predictably in every bridge. The major factors that influence the movement are deck length and changes in moisture and ambient temperature. Various types of open joint systems are used to protect the edges of the concrete deck and transition traffic smoothly across the opening. The open joint system types discussed in this report are the butt, sliding plate, and finger. Closed joint systems also protect the bridge components below the joint from damage due to water, salt, and other roadway contaminants associated with deck runoff. Closed joint system types include field-molded, compression, strip, plug, inflatable, cushion, and modular.