The Highway Capacity Manual A Conceptual and Research History Volume 1: Uninterrupted Flow by Roger . P Roess, and Elena . S Prassas
Preface to The Highway Capacity Manual eBook
For over sixty years, the Highway Capacity Manual has served as a key standard used in planning, design, analysis and operation of the nation’s vast highway systems.
It has been used internationally as well, and has spurred a number of nations to develop their own versions of the document and its methodologies.
It covers every type of highway one can think of, from freeways and rural highways to signalized intersections, urban arterials, and streets.
In the U.S. no highway can be designed without using it; no analysis of traffic impacts can be conducted without using it; no comprehensive highway plan can be developed without using it.
The manual is now in its 5th full edition, but a number of interim documents and revisions have taken place as well, and a new update to the latest edition is, at this writing, underway.
The responsibility for producing the manual and evaluating its use has fallen to the Highway Capacity and Quality of Service Committee of the Transportation Research Board, an arm of the National Academies of Science and Engineering.
The Committee was first formed in 1944, and consisted of eleven members. The Committee was chaired by O.K. Normann, who was already a driving force on the subject of highway capacity and related issues.
The Committee has now grown to 32 members, with a full set of subcommittees in place which involve well over an additional 100 people.
The first two manuals, in 1950 and 1965, were written directly by Committee members. Subsequent manuals have been assembled and produced under contracts with the National Cooperative Highway Research Program, and have involved a variety of contracting agencies.
My first interactions with the Committee came in 1970, when I was a Ph.D. student at the then Polytechnic Institute of Brooklyn (now the NYU Polytechnic School of Engineering).
With my advisor, William McShane, I was working on a research contract aimed at developing a new methodology for weaving areas on freeways.
As a Ph.D. student, I was privileged to meet Powell Walker, one of the original 11 Committee members, and worked on another unrelated project with Nate Cherniak, another of the founding 11.
I also got to work with Jack Leisch, who developed the weaving methodology of the 1965 HCM, and who was an early member of the Committee.