Highway Capacity Manual
Encyclopedia
The Highway Capacity Manual (HCM) is a publication of the Transportation Research Board
(TRB) in the United States
. It contains concepts, guidelines, and computational procedures for computing
the capacity and quality of service of various highway facilities, including freeways, highway
s, arterial road
s, roundabout
s, signalized and unsignalized intersections
, rural highway
s, and the effects of mass transit, pedestrian
s, and bicycle
s on the performance of these systems. There have been five editions with improved and updated procedures from 1950 to 2010, and two major updates to the HCM 1985 edition, in 1994 and 1997. The HCM has been a worldwide reference for transportation and traffic engineering scholars and practitioners, and also the base of several country specific capacity manuals.
).
The following editions were published by the Transportation Research Board
in 1965, 1985, 2000 and 2010. The latest edition HCM 2010 is the culmination of a multi-agency effort (including TRB, AASHTO, and FHWA
) over many years to meet the changing analytical needs and to provide contemporary evaluation tools. The fifth edition, HCM 2010, has been released and is available from TRB.
Transportation Research Board
The Transportation Research Board is a division of the National Research Council, which serves as an independent adviser to the President, the Congress and federal agencies on scientific and technical questions of national importance...
(TRB) in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It contains concepts, guidelines, and computational procedures for computing
Computing
Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...
the capacity and quality of service of various highway facilities, including freeways, 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...
s, arterial road
Arterial road
An arterial road, or arterial thoroughfare, is a high-capacity urban road. The primary function of an arterial road is to deliver traffic from collector roads to freeways, and between urban centres at the highest level of service possible. As such, many arteries are limited-access roads, or feature...
s, roundabout
Roundabout
A roundabout is the name for a road junction in which traffic moves in one direction around a central island. The word dates from the early 20th century. Roundabouts are common in many countries around the world...
s, signalized and unsignalized intersections
Uncontrolled intersection
An uncontrolled intersection is a road intersection where no traffic lights or signs are used to indicate the right-of-way. Mostly, uncontrolled intersections are unmarked. However, in some locations, motorists may be warned by road signage or a warning light...
, rural 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...
s, and the effects of mass transit, pedestrian
Pedestrian
A pedestrian is a person traveling on foot, whether walking or running. In some communities, those traveling using roller skates or skateboards are also considered to be pedestrians. In modern times, the term mostly refers to someone walking on a road or footpath, but this was not the case...
s, and bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
s on the performance of these systems. There have been five editions with improved and updated procedures from 1950 to 2010, and two major updates to the HCM 1985 edition, in 1994 and 1997. The HCM has been a worldwide reference for transportation and traffic engineering scholars and practitioners, and also the base of several country specific capacity manuals.
History
There are more than five decades of research behind the HCM. The first edition of the Highway Capacity Manual was released in 1950 and contained 147 pages broken apart into eight parts. It was the result of a collaborative effort between the Transportation Research Board (TRB) and the Bureau of Public Roads (predecessor to the Federal Highway AdministrationFederal Highway Administration
The Federal Highway Administration is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two "programs," the Federal-aid Highway Program and the Federal Lands Highway Program...
).
The following editions were published by the Transportation Research Board
Transportation Research Board
The Transportation Research Board is a division of the National Research Council, which serves as an independent adviser to the President, the Congress and federal agencies on scientific and technical questions of national importance...
in 1965, 1985, 2000 and 2010. The latest edition HCM 2010 is the culmination of a multi-agency effort (including TRB, AASHTO, and FHWA
Federal Highway Administration
The Federal Highway Administration is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two "programs," the Federal-aid Highway Program and the Federal Lands Highway Program...
) over many years to meet the changing analytical needs and to provide contemporary evaluation tools. The fifth edition, HCM 2010, has been released and is available from TRB.