American Association of State Highway and Transportation Officials.
An American association representing the highway and transportation departments of the 50 U.S. states, the District of Columbia, and Puerto Rico. The association works to develop an integrated national transportation system and develops standards and technical specifications in the fields of highways and transportation.

AASHTO standards cover, among other things, the design, construction, and maintenance of roads and bridges, materials and testing methods, as well as a variety of other areas related to transportation infrastructure. The association also publishes Provisional Standards, which allow new methods and requirements to be used during the research and development stages.

Organization website https://transportation.org/