AASHTO GL-7, Roadway Lighting Design Guide, Seventh Edition (2018), provides an overview of roadway lighting from the perspective of state transportation departments and recommends minimum design parameters. Chapters address master lighting plans, techniques of lighting design, and electrical systems requirements, together with overhead lighting and maintenance considerations. Specific applications are covered for tunnels and underpasses, work zone and temporary lighting, roundabouts, and rest areas and welcome centers. Sky glow and light trespass are treated in a separate chapter, reflecting concern about the environmental effects of outdoor lighting. Agencies may use the guide to warrant and design lighting systems and to incorporate its recommendations into their own roadway lighting policies. It is written for state and local agency engineers and lighting designers responsible for roadway illumination.