The Mission
The American Association of State Highway and Transportation Officials (AASHTO) is a nonprofit, nonpartisan association representing the highway and transportation departments of all 50 states, the District of Columbia, and Puerto Rico. AASHTO serves as a primary standards-setting body, publishing the specifications, test protocols, and technical guidance essential for highway design, construction, and safety. While its roots are in roadways, AASHTO represents all modes of travel, including air, rail, water, public transit, and active transportation.
Whether you are a civil engineer designing a resilient overpass using LRFD specifications, a lab technician seeking accreditation through AASHTO re:source, or a city planner applying “Green Book” principles to urban streetscapes, AASHTO provides the technical foundation for your work. By uniting state-level expertise, the association ensures that the nation’s transportation infrastructure is built to uniform standards of safety, quality, and reliability across every jurisdictional line.
AASHTO publishes the definitive documents that govern the American landscape’s physical infrastructure. The AASHTO LRFD Bridge Design Specifications serve as the base guidance for almost every bridge project managed by state departments of transportation. Additionally, the association’s “Green Book” (A Policy on Geometric Design of Highways and Streets) provides the mathematical and functional requirements for roadway curves, intersections, and lane widths.
Beyond design, AASHTO sets the bar for materials testing. Its Standard Specifications for Transportation Materials provide rigorous protocols for sampling and testing asphalt, concrete, soil, and aggregate. These standards ensure that the materials used in multi-billion-dollar infrastructure projects are durable and consistent. AASHTO also maintains the Manual for Assessing Safety Hardware (MASH), which establishes the crash-testing criteria for guardrails and other safety barriers used to protect motorists nationwide.
AASHTO manages a massive portfolio of technical publications that form the regulatory and engineering backbone of U.S. transportation. Every state department of transportation references AASHTO materials to ensure federal compliance and engineering integrity. By coordinating these standards, AASHTO prevents a patchwork of conflicting state rules, allowing for a seamless national highway system that prioritizes driver safety and infrastructure longevity.
A critical arm of the association is AASHTO resource, a program that accredits testing laboratories and provides quality assurance for the entire industry. AASHTO also acts as a vital liaison between state agencies and the federal government. By cooperating with the Federal Highway Administration (FHWA), the association helps shape national policy and research. This collaborative model ensures that new innovations in construction and safety are quickly vetted and integrated into standard practice.
AASHTO was founded in 1914 as the American Association of State Highway Officials (AASHO). In its early years, the organization focused on the monumental task of coordinating state-level highway construction during the dawn of the automobile age. By working closely with federal authorities, the association helped establish the early frameworks for national highway policy and standardized the way states approached public works projects.
In 1973, the name was changed to include “Transportation,” reflecting a shift toward a multimodal approach. This evolution allowed the association to address the growing complexities of rail, air, and water transit alongside traditional roadways. Today, AASHTO is headquartered in Washington, D.C., and its influence has reached far beyond U.S. borders.
The association now includes non-voting members from across the globe, including Canadian provinces and transportation agencies in Nigeria, Turkey, and Hong Kong. This international reach proves that AASHTO’s rigorous testing protocols and design specifications are recognized as global benchmarks for excellence in civil engineering and public safety.
The core of AASHTO is its voting membership, comprised of the transportation departments of the 50 states, D.C., and Puerto Rico. However, the organization thrives on a broader network of associate members, including U.S. cities, counties, and international agencies. This inclusive structure ensures that a diverse range of perspectives—from local urban planning to international logistics—informs the association’s technical output.
Decisions within AASHTO are driven by a committee structure staffed by volunteers from state agencies. These committees use a consensus-based model to update specifications and policy guidance. For professionals, participating in these task forces offers a direct way to influence the technical standards that will govern the next generation of American infrastructure, from smart highways to high-speed rail corridors.
AASHTO is deeply committed to the professional growth of the transportation workforce. Through specialized training programs and technical resources, the association helps engineers and technicians master the nuances of bridge design, safety evaluation, and materials testing. These programs are essential for maintaining the high level of technical proficiency required to manage modern, multi-modal transportation networks.
AASHTO resource plays a major role in education by providing proficiency testing and laboratory accreditation. Most state agencies require this accreditation for any laboratory submitting results for highway projects.
By maintaining these high standards of quality assurance, AASHTO ensures that the engineers and technicians of today are equipped with the most accurate data and the most advanced technical knowledge available.
About AASHTO
What does AASHTO stand for?
AASHTO stands for the American Association of State Highway and Transportation Officials. It is a nonprofit organization representing the transportation departments of all 50 U.S. states, D.C., and Puerto Rico.
What is AASHTO known for?
AASHTO is the primary author of the standards used for highway design and bridge construction in the U.S. It is most famous for the “Green Book” (geometric design) and the LRFD Bridge Design Specifications.
What is AASHTO resource?
It is the association’s accreditation program for testing laboratories. It ensures that the labs testing construction materials like asphalt and concrete meet strict quality and accuracy requirements.
What is the difference between AASHTO and ASTM?
AASHTO focuses specifically on transportation infrastructure and state-level engineering needs. ASTM International develops standards for a much broader range of general materials and industries. The two organizations often cooperate on testing methods.
Is AASHTO a federal government agency?
No. AASHTO is an independent nonprofit association. While it works very closely with the Federal Highway Administration, it is governed by the individual states, not the federal government.
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