AASHTO LRFDTUN-1, LRFD Road Tunnel Design and Construction Guide Specifications, First Edition (2017), applies load and resistance factor design to highway tunnels and covers their design, evaluation, and rehabilitation. Section 1 sets out purpose and scope, definitions, and the design philosophy, including limit states, ductility, redundancy, and operational importance. The remaining sections carry that philosophy into tunnel-specific requirements across the ten sections of the document. Cut-and-cover, bored, mined, and immersed construction methods are within scope, and structures internal to a tunnel that support roadways over ventilation plenums or other openings are included. Water conveyance, utility, transit, and rail tunnels, and shafts, are not covered. The specifications are intended for tunnel designers, structures engineers, and the agencies that own road tunnel assets.