AASHTO, the American
Association of State Highway and Transportation Officials, is a
standards setting body which publishes specifications, test protocols
and guidelines which are used in highway design and construction
throughout the United States. Despite its name, the association
represents not only highways but air, rail, water, and public
transportation as well.
The voting membership of AASHTO consists
of the Department of Transportation of each State in the United States,
as well as that of Puerto Rico and the District of Columbia. The United
States Department of Transportation, some U.S. cities, counties and
toll-road operators, most Canadian provinces as well as the Hong Kong
Highways Department, the Turkish Ministry of Public Works and Settlement
and the Nigerian Association of Public Highway and Transportation
Officials have non-voting associate memberships.
The American Association of State Highway Officials
(AASHO) was founded on December 12, 1914. Its name was changed to
American Association of State Highway and Transportation Officials on
November 13, 1973. The name change reflects a broadened scope to cover
all modes of transportation, although most of its activities are still
specific to highways.
While AASHTO is not a
government body, it does possess quasi-governmental powers in the sense
that the organizations that supply its members customarily obey most
AASHTO decisions. It is an example of a general tendency in the American
style of government to outsource many governmental functions to
nongovernmental organizations, whose decisions are then routinely
ratified by appropriate government agencies.
Some noteworthy AASHTO publications are:
A Policy on Geometric Design of Streets
and Highways, often called “The Green Book” because of the color of its
cover. This book covers the functional design of roads and highways
including such things as the layout of intersections, horizontal curves
and vertical curves.
Standard Specifications for Transportation Materials and Methods of Sampling and Testing.
In addition to its publications AASHTO performs or cooperates in research projects. One such project is the AASHO Road Test, which is a primary source of data used when considering transport policies and the structural design of roads. Much of AASHTO’s current research is performed by the National Cooperative Highway Research Program (NCHRP) which is administered by the Transportation Research Board (TRB) of the National Research Council.
Standard Specifications for Transportation Materials and Methods of Sampling and Testing.
In addition to its publications AASHTO performs or cooperates in research projects. One such project is the AASHO Road Test, which is a primary source of data used when considering transport policies and the structural design of roads. Much of AASHTO’s current research is performed by the National Cooperative Highway Research Program (NCHRP) which is administered by the Transportation Research Board (TRB) of the National Research Council.
The AASHTO Materials Reference
Laboratory (AMRL) accredits laboratories. AMRL accreditation is often
required to submit test results to State DOTs. For example, a contract
for the construction of a highway bridge may require a minimum
compressive strength for the concrete used. The contract will specify
AASHTO Test Designation T22 “Compressive Strength of Cylindrical
Concrete Specimens” as the means of determining compressive strength.
The laboratory performing T22 will be required to be accredited by AMRL
in that test.
AASHTO coordinates the numbering of Interstate Highways, U.S. Highways and U.S. Bicycle Routes.
