Committee Information & Background

About TRB

The Transportation Research Board (TRB) is a unit of the National Research Council, a private, nonprofit institution that is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering. The Board's mission is to promote innovation and progress in transportation by stimulating and conducting research, facilitating the dissemination of information, and encouraging the implementation of research results. (http://www.trb.org)

TRB fulfills this mission through the work of its standing technical committees and task forces addressing all modes and aspects of transportation; publication and dissemination of reports and peer-reviewed technical papers on research findings; administration of two contract research programs; conduct of special studies on transportation policy issues at the request of the U.S. Congress and government agencies; operation of an on-line computerized file of transportation research information; and the hosting of an annual meeting of transportation professionals from throughout the United States and abroad.

About HCQSC (AHB40)

The Highway Capacity and Quality of Service Committee is designed "AHB40" by TRB. AHB40 is grouped within Division “A” (Technical Activities), Group H (Operations and Maintenance), Section “B” (Operations), Committee "40" of the Transportation Research Board.

The Highway Capacity and Quality of Service (HCQS) Committee (AHB40) is concerned with investigating the those physical and non-physical factors which affect capacity, traffic flow, comfort, convenience, and safety; and is responsible for developing computational techniques for quantifying the effect of these factors on capacity, traffic flow; and quality of service.

AHB40 acts as the primary overseer for research and enhancement of the Highway Capacity Manual (HCM.) The HCM documents procedures and guidelines for the measurement, analysis, and interpretation of data quantifying highway capacity and quality of service.

Committee Membership

Responsibility for oversight and coordination of committee activities rests collectively with the 32 (plus emeritus) members appointed by TRB to serve staggered, 3-year terms. Currently, the HCQS committee is composed of 27 members. The chair of the committee is Dr. Tom Creasey and the committee secretary and webmaster is Dr. Janice Daniel.

Click here to view list of full committee members

The committee meets twice a year, once in Washington D.C. at the Annual TRB meeting in January of each year, and the second time each year during the summer at various locations throughout the United States and the World. The committee membership is configured according to TRB Guidelines with broad and diverse representation from many sectors, however, all members represent the scientific interests of the professional community as a whole, and no member represents any particular organization or constituency.

Committee Organization

The bulk of the work of the Committee is conducted by our many subcommittees and task forces. Over 250 people from around the world participate in subcommittee activities.

The subcommittees and task forces are organized into four general groups: 

  • Group 1 - Administration, chaired by Dr. Janice Daniel; 
  • Group 2 - Uninterrupted Flow, chaired by Dr. Bastian Schroeder; 
  • Group 3 - Interrupted Flow, chaired by Mr. Christopher Kinzel; and 
  • Group 4 - Cross-Cutting Issues, chaired by Mr. Paul Ryus.

Committee History

The Highway Capacity and Quality of Service committee is one of the oldest and most active of all TRB committees. Originally founded in 1944 the volunteer committee membership has delivered five major revisions to the Highway Capacity Manual.

Getting Involved

Committee and subcommittee meetings are open to all interested in contributing to the advancement of the committee’s activities. People in the audience are encouraged to contribute to the discussions. Information on schedules, agenda, and locations for upcoming meetings can be found at the committee’s website:


  1. The first step to participating in Committee activities is to register on the committee’s website as a “friend of the committee”. In doing so, you will receive electronic notices of upcoming committee activities. You can sign up as a friend of individual subcommittees and/or the full committee.
  2. The second step is to become an active member of one or more of the Committee’s subcommittees. Much of the real work on the Highway Capacity Committee occurs at the Subcommittee level. Subcommittee membership is determined by the subcommittee chair, so the best way to become a member of a subcommittee is to show up at subcommittee meetings and to volunteer to help the subcommittee chair carry out one or more tasks for the subcommittee. There are no formal limits on the number of subcommittee members or the length of service on the subcommittee. Visit the committee's working website to identify the individual subcommittees and their respective chairs.

Committee membership is limited by TRB to 30 members that are appointed by TRB to 3-year terms on recommendation of the committee chair. Every 3 years, according to TRB policy, one-third of the membership is rotated off of the committee.