American Association of State Highway and Transportation Officials
Encyclopedia
AASHTO, the American Association of State Highway and Transportation Officials, is a standards setting body which publishes specifications, test protocols
and guideline
s 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
province
s as well as the Hong Kong
Highways Department, the Turkish
Ministry of Public Works and Settlement and the Nigeria
n Association of Public Highway and Transportation Officials have non-voting associate memberships.
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 expert organizations, whose decisions are then routinely ratified by appropriate government agencies.
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.
Quality control
Quality control, or QC for short, is a process by which entities review the quality of all factors involved in production. This approach places an emphasis on three aspects:...
and guideline
Guideline
A guideline is a statement by which to determine a course of action. A guideline aims to streamline particular processes according to a set routine or sound practice. By definition, following a guideline is never mandatory. Guidelines are not binding and are not enforced. A guideline is a statement...
s which are used in highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...
design and construction throughout the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. 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
Department of Transportation
The Department of Transportation is the most common name for a government agency in North America devoted to transportation. The largest is the United States Department of Transportation, which oversees interstate travel. All U.S. states, Canadian provinces, and many local agencies also have...
of each state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, as well as that of Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
and the District of Columbia. The United States Department of Transportation
United States Department of Transportation
The United States Department of Transportation is a federal Cabinet department of the United States government concerned with transportation. It was established by an act of Congress on October 15, 1966, and began operation on April 1, 1967...
, some U.S. cities, counties and toll-road operators, most Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
province
Province
A province is a territorial unit, almost always an administrative division, within a country or state.-Etymology:The English word "province" is attested since about 1330 and derives from the 13th-century Old French "province," which itself comes from the Latin word "provincia," which referred to...
s as well as the Hong Kong
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
Highways Department, the Turkish
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
Ministry of Public Works and Settlement and the Nigeria
Nigeria
Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...
n Association of Public Highway and Transportation Officials have non-voting associate memberships.
Purpose
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 expert organizations, whose decisions are then routinely ratified by appropriate government agencies.
Publications
Some noteworthy AASHTO publications are:- A Policy on Geometric Design of Highways and Streets, 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.
- AASHTO LRFD Bridge Design Specifications. This manual is the base bridge design manual that all DOTs use across the US.
In addition to its publications, AASHTO performs or cooperates in research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
projects. One such project is the AASHO Road Test
AASHO Road Test
The AASHO Road Test was a series of experiments carried out by the American Association of State Highway and Transportation Officials to determine how traffic contributed to the deterioration of highway pavements...
, 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
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academies, carrying out most of the studies done in their names.The National Academies include:* National Academy of Sciences...
.
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
Compressive strength
Compressive strength is the capacity of a material or structure to withstand axially directed pushing forces. When the limit of compressive strength is reached, materials are crushed. Concrete can be made to have high compressive strength, e.g...
for the concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
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.
See also
- Standards organizations
- Technical standard
- International standards
- National Transportation Communications for Intelligent Transportation System ProtocolNational Transportation Communications for Intelligent Transportation System ProtocolThe National Transportation Communications for Intelligent Transportation System Protocol is a family of standards designed to achieve interoperability and interchangeability between computers and electronic traffic control equipment from different manufacturers.The protocol is the product of a...
(NTCIP)