As highway congestion continues to be a problem in many areas, states are looking to construct or expand highway projects. When a state department of transportation (DOT) receives federal funding for highway projects from the Federal Highway Administration (FHWA), the projects must comply with the National Environmental Policy Act (NEPA), the Davis-Bacon prevailing wage requirement, the Disadvantaged Business Enterprise (DBE) program, and the Buy America program. While complying with these requirements, states must use limited transportation dollars efficiently. As requested, GAO addressed (1) the types of benefits and costs associated with these requirements for federal-aid highway projects; (2) the influence of these federal requirements on states’ decisions to use nonfederal or federal funds for highway projects; and (3) the challenges associated with the federal requirements and strategies used or proposed to address the challenges. To complete this work, GAO reviewed 30 studies, surveyed DOTs in all states and the District of Columbia, and interviewed transportation officials and other stakeholders.