Development of the Human Factors Guidelines for Road Systems: Third Edition (2025)
Chapter: Front Matter
Development of the Human Factors Guidelines for Road Systems, Third Edition
John L. Campbell
Liberty Hoekstra-Atwood
Chris Monk
Audra Fraser
Exponent
Seattle, WA
Ingrid Potts
Texas A&M Transportation Institute
Lee’s Summit, MO
Darren Torbic
Texas A&M Transportation Institute
State College, PA
Conduct of Research Report for NCHRP Project 22-46
Submitted June 2024
NCHRP Web-Only Document 425
Development of the Human Factors Guidelines for Road Systems, Third Edition
© 2025 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved.
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state department of transportation (DOT) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research.
Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 initiated an objective national highway research program using modern scientific techniques—the National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration (FHWA), United States Department of Transportation.
COPYRIGHT INFORMATION
Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein.
Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP.
DISCLAIMER
This material is based upon work supported by the FHWA under Agreement No. 693JJ32350025. The opinions, findings, and conclusions or recommendations expressed or implied in this publication are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; the FHWA; or the program sponsors.
The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.
The Transportation Research Board, the National Academies, and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of the report.
The information contained in this document was taken directly from the submission of the author(s). This material has not been edited by TRB.
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COOPERATIVE RESEARCH PROGRAMS
CRP STAFF FOR NCHRP WEB-ONLY DOCUMENT 425
Monique R. Evans, Director, Cooperative Research Programs
Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program
David Jared, Senior Program Officer
Sheila A. Moore, Program Associate
Natalie Barnes, Director of Publications
Heather DiAngelis, Associate Director of Publications
Jennifer Correro, Assistant Editor
NCHRP PROJECT 22-46 PANEL
Field of Design – Area of Vehicle Barrier Systems
Martha Alicia Brown, Illinois Department of Transportation, Springfield, IL (Chair)
Paul J. Carlson, Automated Roads, Greensboro, NC
John C. Milton, Washington State Department of Transportation, Olympia, WA
Deirdre T. Nash, New Hampshire Department of Transportation, Concord, NH
Bernadette Estioko Phelan, Phelan International LLC, Scottsdale, AZ
T. Scott Smith, Louisiana State University, Lafayette, LA
Samuel C. Tignor, Virginia Polytechnic Institute and State University, McLean, VA
Rosemarie Anderson, FHWA Liaison
Kelly K. Hardy, AASHTO Liaison
Contents
2.0 Objectives, Methods, and Results of Tasks 1-6
2.1 Task 1: Assess Existing Human Factors Literature
2.2 Task 2: Develop Draft Practitioner Survey
2.3 Task 3: Conduct Practitioner Survey
2.4 Task 4: Develop Recommendations to Update the Content of the HFG
2.5 Task 5: Develop and Submit Interim Report
2.6 Task 6: Develop Updated Content for the HFG4
3.0 Recommendations for Future Research Needs
NCHR Web-Only Document 425 contains the conduct of research report for NCHRP Project 22-46 and accompanies NCHRP Research Report 1148: Human Factors Guidelines for Road Systems, Third Edition. Readers can read or purchase NCHRP Research Report 1148 on the National Academies Press website (nap.nationalacademies.org).
List of Figures
Figure 1. Overview of the Chapter Prioritization Process
Figure 2. General Process for Developing/Revising Individual Guidelines for the HFG4
Figure 3. Presentation format from the HFG2 and HFG3
List of Tables
Table 1. HFG4 Survey Recipients
Table 2. Results of the prioritization process and priorities for the HFG4
Table 3. Results of initial searches for questionable terms and phrases in the HGF2 and HFG3
Table 4. Proposed Modifications to the Project Schedule
Acronyms and Abbreviations
| AASHTO | American Association of State Highway and Transportation Officials |
| BES | Best Evidence Synthesis |
| DOT | Department of Transportation |
| FHWA | Federal Highway Administration |
| HF | Human Factors |
| HFG | Human Factors Guidelines for Road Systems |
| HFG2 | Human Factors Guidelines for Road Systems, Second Edition |
| HFG3 | Human Factors Guidelines for Road Systems, Third Edition |
| HFG4 | Human Factors Guidelines for Road Systems, Fourth Edition |
| HSM | Highway Safety Manual |
| IR | Interim Report |
| ITE | Institute of Transportation Engineers |
| MUTCD | Manual on Uniform Traffic Control Devices |
| NCHRP | National Cooperative Highway Research Program |
| NHTSA | National Highway Traffic Safety Administration |
| RSA | Road Safety Audit |
| TRB | Transportation Research Board |
| TRID | Transportation Research International Documentation |
