TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 538: Practices for Online Public Involvement summarizes current practices regarding online public participation strategies being used by state departments of transportation (DOTs), as well as explores the effectiveness of using these strategies and tools. Online public participation methods offer agencies the potential for expanded participation and also present new challenges and demand new thinking about the appropriate mix of techniques in a public participation program, communication protocols, staffing and skill requirements, and how best to integrate emerging online engagement tools with traditional face-to-face methods such as public meetings.