Transportation Research Board ACP50
Committee on Traffic Flow Theory and Characteristics



  • Committee Members [map of member locations]
  • FAQ about committee membership
  • Current membership: 24 members (1 vacancy) + 5 international + 4 young + 2 state DOT + 2 emeritus = 37
  • Current Members Affiliation
    Dr. Rafegh Aghamohammadi University of Michigan
    Dr. Ramachandran Balakrishna Caliper Corporation
    Dr. Robert L. Bertini Oregon State University
    Dr. Danjue Chen University of Massachussets Amherst
    Dr. Biagio Ciuffo JRC: European Commission Joint Research Centre, Italy
    Dr. Benjamin Coifman Ohio State University
    Dr. Maria Laura Delle Monache University of California, Berkeley
    Dr. Tamara Djukic ERTICO, Belgium
    Dr. Vikash Gayah Pennsylvania State University
    Dr. Eric Gonzales University of Massachusetts, Amherst
    Dr. Weihua Gu Hong Kong Polytechnic University, Hong Kong
    Dr. Ilgin Guler Pennsylvania State University
    Dr. Jack Haddad Technion Israel Institute of Technology, Israel
    Dr. Samer Hamdar, Secretary George Washington University
    Dr. Rachel James Federal Highway Administration
    Dr. Lina Kattan University of Calgary, Schulich, Canada
    Dr. Jiwon Kim University of Quennsland, Australia
    Dr. Panchamy Krishnakumari Delft University of Technology, the Netherlands
    Dr. Ludovic Leclercq, Chair Université Gustave Eiffel - ENTPE, France
    Dr. Hani Mahmassani Northwestern University
    Dr. Irene Martinez Delft University of Technology, the Netherlands
    Dr. Kaan Ozbay New York University
    Dr. Marco Rinaldi AMS Institute, the Netherlands
    Dr. Meead Saberi University of New South Wales, Australia
    Dr. Raphael Stern University of Minnesota
    Mr. James Sturrock Federal Highway Administration
    Dr. Alireza Talebpour University of Illinois, Urbana-Champaign
    Dr. Silvia Varotto Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland
    Dr. Francesco Viti University of Luxembourg, Luxembourg
    Dr. Zhongren Wang California Department of Transportation
    Dr. Daniel Work Vanderbilt University
    Dr. Hwasoo Yeo Korea Advanced Institute of Science and Technology, South Korea
    Dr. Kenan Zhang ETH Zurich: Eidgenossische Technische Hochschule Zurich, Switzerland
    Dr. Ali Zockaie Michigan State University
    Emeritus Members Affiliation
    Dr. Nathan H. Gartner

    University of Massachusetts, Lowell

    Dr. Alexander Skabardonis University of California, Berkeley
    Staff Affiliation

    Richard A. Cunard

    TRB Staff Representative

    Subcommittee Chair

    Crowd Flow Dynamics, Modeling, and Management AHB45(2)

    Majid Sarvi/Winnie Daamen/Serge Hoogendoorn

    Traffic Flow Modeling for Connected and Automated Vehicles AHB45(3) Samer Hamdar
    Research Problem Statements Vikash Gayah

    Paper Review

    Ludovic Leclercq


    Jiwon Kim

    Midyear Meetings

    Ludovic Leclercq

    Outreach and Diversity

    • Committee Communications
    • TFTC Webinar
    • TFTC Journal Club
    • Committee Website

    Samer Hamdar/Alireza Talebpour

    • Samer Hamdar
    • Jorge Laval
    • Alireza Talebpour
    • Ali Zockaie/Robert Bertini
    Operations Section ACP00 Affiliation

    Robert L. Bertini, Chair

    Oregon State University

    Safety and Operations Group AC000 Affiliation

    Michael Griffith, Chair

    Advanced Mobility Analytics Group Pty Ltd

    Past Committee Chairs (affiliations at time of appointment):

    • Committee on Traffic Flow Theory (1963-1970) TO-9
      • D.L. Gerlough, Planning Research Corp. (1963)
      • Donald E. Cleveland, University of Virginia (1964-1967)
    • Committee on Characteristics of Traffic Flow (1963-1970) TO-12
      • Harold L. Michael, Purdue University (1963-1964)
      • Joseph C. Oppenlander, University of Vermont (1964-1968)
      • Donald C. Capelle, Alan M. Voorhees and Associates, Inc. (05/01/1968-01/31/1970)
    • Committee on Speed Characteristics (1939-1963) TO-13A
      • Burton W. Marsh, AAA (01/01/1939-12/31/1954)
      • Harold L. Michael, Purdue University (01/01/1955-01/31/1963)
    • Committee on Traffic Flow Theory and Characteristics (1971-present) ACP50
      • Donald G. Capelle, Alan M. Voorhees and Associates, Inc. (02/01/1971 - 01/31/1974)
      • Kenneth W. Crowley, The Pennsylvania State University (02/01/1974 - 01/31/1980)
      • John J. Haynes, University of Texas at Arlington (02/01/1980 - 01/31/1986)
      • Carroll J. Messer, Texas A&M University (02/01/1986 - 01/31/1992)
      • Hani S. Mahmassani, University of Texas at Austin (02/01/1992 - 01/31/2000)
      • Nathan H. Gartner, University of Massachusetts Lowell (02/01/2000 - 04/14/2009)
      • Robert L. Bertini, Portland State University (04/15/09 - 04/14/2015)
      • Soyoung Ahn, University of Wisconsin Madison (04/15/2015 - 04/14/2021)
      • Ludovic Leclercq, Université Gustave Eiffel - ENTPE (04/15/2021 - Present)
    Previous Committee Leaders

    Source: Gerlough family papers, University of Idaho
    Daniel Lauder Gerlough (b. 1916. d. 1977) (Founding Chair 1963)
    BSEE Caltech (1937), MSEE UC Berkeley (Thesis: The logical design of an arithmetic unit for an electronic digital computer 1948), PhD Engineering UCLA (Thesis: Simulation of freeway traffic on a general-purpose discrete-variable computer, 1955) worked at the Institute of Transportation and Traffic Engineering at the University of California at Los Angeles, TRW, Planning Research Corporation, and finally at the University of Minnesota. Known as "Mr. Poisson," he was a registered Professional Engineer in the state of California and was a member of the Institute of Radio Engineers, American Institute of Electrical Engineers and the Institute of Traffic Engineers. He co-authored Use of Poisson Distribution in Highway Traffic (1955) the Introduction to Traffic Flow Theory (1964) and the Monograph on Traffic Flow Theory (1975). Here is a link to a University of Minnesota tribute.

    Donald E. Cleveland (b. 1929) University of Virginia (Chair 1964-1967)
    BS MIT 1949, MS Yale 1959, PhD Texas A&M 1962. Following experience at Yale, Texas A&M and the University of Virginia he was Professor of Civil Engineering, University of Michigan 1965-1988. He led the traffic engineering team at the University of Michigan's Highway Safety Research Institute (HSRI). Cleveland authored two texts and contributed to professional handbooks and research emphasizing highway safety and operational characteristics of highway design and control measures. He was a research scholar at the Transportation Research Board working on the 3-R safety program. He is a Fellow of ITE. Here is a link to a University of Michigan memoir

    Harold L. Michael (b. 1920, d. 1999), Purdue University (Chair 1963-1964)
    BS Purdue 1950, MS Purdue 1951, Hon PhD, Pursue, 1992. Professor of Civil Engineering at Purdue University 1954-retirement. Active with Transportation Research Board and ITE, recipient of many awards. Here is a link to ITE's honorary membership listing. Tribute by Kumares Sinha.
    Joseph Clarence Oppenlander (b. 1931) University of Vermont (Chair 1964-1968)
    BSCE Case Institute of Technology, MSCE Purdue, PhD University of Illinois. Professor of Civil Engineering University of Vermont, recipient of many awards, active with ITE. Through his consulting firm, TRANSOP, Inc., he authored over 100 major technical reports for various private organizations and public agencies. Professor Emeritus at University of Vermont. Co-author of Fred the Little Black Truck.
    Donald Gene Capelle (b. 1931 d. 2016) Alan M. Voorhees and Associates, Inc. (Chair 05/01/1968-01/31/1970, 02/01/1971 - 01/31/1974)
    Born 1931 in Anderson, SC, BS in Engineering Clemson, MS, Ph.D. in Transportation Engineering at Texas A&M. Died 2016 in California. Don worked for the Automotive Safety Foundation from 1962 to 1967, Alan M. Voorhees and Associates also known as PRC/Voorhees from 1967 until 1983 and then for Parsons Brinckerhoff Quade and Douglas until his retirement in 2000. Throughout his career he was actively involved in technical work related to the operation and design of highway facilities with major emphasis on high occupancy vehicle facilities and for many years served as Chair of the TRB Committee on High Occupancy Vehicle Systems, and later as Emeritus Member.
    Kenneth W. Crowley (b. 1929 d. 2012), The Pennsylvania State University (Chair 02/01/1974 - 01/31/1980)
    BSCE Yale 1949, MS and PhD New York Polytechnic Institute 1972. Served in U.S. Air Force. Worked for New York Port Authority and taught at Penn State University for a number of years. Joined Institute of Research where he remained until his retirement. Served as expert witness and enjoyed reading and spending time with his children and grandchildren.

    John Jackson Haynes (b. 1925 d. 1996), University of Texas at Arlington (Chair 02/01/1980 - 01/31/1986)
    Graduated from Texas Technical College, 1949. Ph.D. in Civil Engineering from Texas A&M University, 1964.Professor of Civil Engineering, Head of Civil Engineering Department, and Director of the Public Transportation Center at the University of Texas at Arlington. Navy veteran WWII (Purple Heart).
    Carroll J. Messer, Texas A&M University (Chair 02/01/1986 - 01/31/1992)
    PhD Texas A&M, 1969, Professor Texas A&M until 2004. Joined the Texas A&M faculty as an assistant professor and served as research engineer at Texas Transportation Institute (TTI). He led TTI’s Transportation Systems Division for five years and was program manager 12 years of its Traffic Operations Program. Developed the PASSER family of traffic signal optimization computer programs. Known for his expertise in computer-based, real-time traffic control systems. Messer has been honored with the Distinguished Service Award from both the Institute of Transportation Engineers (ITE) and the Transportation Research Board (TRB).
    Hani S. Mahmassani, Northwestern University (Chair 02/01/1992 - 01/31/2000)
    BSCE University of Houston 1976, MSCE Purdue 1978, PhD MIT 1982. Professor of Civil Engineering at University of Texas Austin (1982-2002), University of Maryland (2002-2007), Northwestern University 2007-present. Recipient of numerous awards, member of numerous committees, editor of significant journals, author of numerous publications, and teacher and advisor of more than 40 PhD students across a wide array of transportation subjects. Continues as active member of committee.
    Nathan H. Gartner, University of Massachusetts Lowell (Chair 02/01/2000 - 04/14/2009)
    BS Engineering Technion, MS Engineering, Technion, Sc.D. Transportation Engineering and Operations Research Technion. Professor of Civil Engineering at University of Massachusetts Lowell. Performed research in traffic flow models and transportation systems, with a focus on urban traffic control strategies and systems and transportation network analysis, fields in which he is widely published and internationally recognized. Developed traffic control and network optimization methods including: The Generalized Combination Method, MITROP, MAXBAND and MULTIBAND. Developed OPAC (Optimization Policies for Adaptive Control), the first real-time, traffic-adaptive signal control strategy to be deployed through the RT-TRACS program in the U.S. Emeritus member of committee.
    Robert L. Bertini, Oregon State University (Chair 04/15/2009 - 04/14/2015)
    BSCE California Polytechnic State University San Luis Obispo, MSCE San Jose State University, PhD University of California Berkeley. Professor of Civil and Environmental Engineering at Portland State University (2000-2014), Deputy Administrator of Research and Innovative Technology Administration at U.S. Department of Transportation, and visiting professor at the Delft University of Technology. On the faculty at California Polytechnic State University San Luis Obispo, Department of Civil and Environmental Engineering (2014-2016). Director of the Center for Urban Transportation Research (CUTR) and Professor of Civil and Environmental Engineering at the Unviersity of South Florida (2016-2020). School Head and Professor of Civil and Construction Engineering, Oregon State University (2020-Present) Continues as active friend of the committee. Serving as chair of TRB Operations Section 2014-2022.
    Soyoung Ahn, University of Wisconsin, Madison (Chair 04/15/2015 - 04/14/2021)
    BSCE Ohio State University, MSCE and PhD University of California Berkeley. Postdoctoral Scholar, Civil and Environmental Engineering, Portland State University (2005-2006). Assistant/Assoiate Professor of Civil, Environmental and Sustainable Engineering at Arizona State University (2006-2013). Associate/Full Professor, Civil and Environmental Engineering, University of Wisconsin-Madison (2013-Present). Executive Director of Mid-America Freight Coalition (MAFC), and Associate Chair for Constructed Facilities



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