The Highway Capacity Manual (HCM) is 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, signalized and unsignalized intersections, rural highways, and the effects of transit, pedestrians, and bicycles on the performance of these systems. The first edition of the Highway Capacity Manual was released in 1950. 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 Administration).
The new edition HCM 2000 was released in late 2000. It is the culmination of a multi-agency effort (including TRB, AASHTO, and FHWA) over 15 years to meet the changing analytical needs and to provide contemporary evaluation tools.
