Human Factors Guidelines for Road Systems 2021 Update, Volume 2: Conduct of Research Report (2022)

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3 SECTION 2: OBJECTIVES, METHODS, AND RESULTS OF TASKS 1-5 This section describes each task performed in preparation for developing a work plan for competing the HFG3. Specific tasks included: ● Task 1: Project Management, ● Task 2: Conduct Kickoff Meeting, ● Task 3: Identify Necessary Revisions in the Existing HFG, ● Task 4: Develop and Implement a User Feedback Plan, and ● Task 5: Conduct Initial Literature Review to Identify Potential Guideline Content. The overall goal of these tasks was to identify requirements and available resources for developing the Work Plan in Task 6. The first two tasks were administrative in nature: specifically, to (a) assemble a Working Group to advise the research team on project work, and (b) communicate the project plan and schedule to the project panel. The objectives of the subsequent tasks were to gather information about the current state of the HFG, what users need or want in the HFG, and what research sources are available to update the HFG. The results of Tasks 3, 4, and 5, with input and guidance from the Working Group, were used to inform the development of the Work Plan in Task 6. Figure 1 illustrates the relationship between project tasks and the workflow used to develop the work plan. Figure 1. Overview of the relationship between project tasks.

4 This section is organized by task. Each task description includes the objectives, methods, and results associated with the activities performed in the task. Task 1: Project Management The key objectives of the Project Management task were to: provide monthly and quarterly progress report on the project to NCHRP, establish a project Working Group, coordinate this project with other NCHRP projects, and make presentations to relevant AASHTO and/or TRB Committees. A project Working Group was identified in consultation with the project panel, and Working Group members were recruited. The role of the Working Group was to provide insight and guidance by industry members to inform and guide the development of relevant guidelines that are meaningful and useful to the broadest audience. With one exception, all individuals recommended by the project panel agreed to participate on the Working Group. The Working Group consisted of 11 members from federal government, state DOTs, academia, and independent consultants. A list of Working Group members was provided in the Task 7 Interim Report. Presentations were made during the kickoff meeting and the meeting to present the Task 7 Interim Report to the project panel. Two additional presentations were made at TRB annual meetings during the conduct of the project: 1. Roadway Design and Operation - Using Human Factors to Guide Data-Driven Decision- Making, which was a workshop presentation at the TRB 97th Annual Meeting. 2. Human Factors Guidelines for Road Design Version 3.0. Status Update, January 2020 Presented at the TRB 99th Annual Meeting. Task 2: Conduct Kickoff Meeting The purpose of the Task 2 kickoff meeting with the project panel was to: 1) discuss the administration of this research project, and 2) to discuss the project’s objectives, planned course of action, milestones and deliverables, and any other issues that Battelle or Program staff identified. Prior to the meeting, a slide set was developed by the project team and sent to NCHRP for distribution to the project panel. The Task 2 kickoff meeting was held via teleconference to discuss the administration of this research project, and the project’s objectives, planned course of action, milestones and deliverables, and research challenges. The slides for this meeting are provided in Appendix B of the Task 7 Interim Report. Task 3: Identify Necessary Revisions in Existing HFG The objective of this task was to review the existing HFG for errors, inconsistencies, and duplications in content that need modification. Three researchers from Battelle conducted a thorough review of the entire HFG to identify specific errors, inconsistencies, and duplications in content that needed modification in the Third Edition. The review included introductory materials, individual guidelines, figures, tables, equations, citations to specific sources, glossary/index entries, etc. The review also included notes from the pilot studies conducted with

5 five state DOTs in 2012-2014, as well as the notes from the HFG training sessions conducted for the FHWA in 2014 to identify such issues that have been raised in the past. A list of items identifying errors and inconsistencies in the HFG2 was developed, and the errors related to updated chapters were addressed during the updates. The full list of errors was provided in the Task 7 Interim Report. Task 4: Develop and Implement a User Feedback Plan An internet-based survey was conducted to identify how users are using the HFG; whether the format, content, and references are meeting users’ needs; and what priorities users and potential users have for new topics and updated chapters. The methods used to conduct the survey are documented in the Task 7 Interim Report. In brief, project panel members, Working Group personnel, and expected users were asked to respond to questions that indicate how they use the HFG; opinions about format, content, and quality of the current HFG; what topics in the current HFG are most/least useful; and what new topics they would like to see included in future editions. 258 respondents answered the survey from a variety of governmental, private, and academic backgrounds. The majority (53%) listed Traffic Safety as their primary job responsibility, while 43% listed Traffic/Transportation Studies and 41% listed Roadway Design/Engineering. 241 participants (99%) reported holding at least a bachelor’s degree, and they ranged in experience from 1-50 years. Finally, 153 (59.3% of the sample) participants reported they had not heard of, or had never read or used the HFG, and received the truncated survey. The remaining 105 participants had at least read some of, or used, the HFG and received the full survey. From the main body of the survey, several key trends emerged which are summarized here: ■ In terms of ease-of-use, clarity, and formatting, the substantial majority of respondents rate the HFG as equivalent to or better than other design guides. When asked if specific formatting or features should be changed, the most common response was updating the intended users and reaching a wider audience.  Interest in cross-referencing the HFG with other guides was congruent with use of other guides (i.e., 82% reported using the MUTCD, 76% reported interest in cross- referencing the HFG and MUTCD).  95% of respondents (users and non-users) reported interest in an interactive web- based application version of the HFG. ■ The applications of the HFG as reported by users, along with the most useful chapters, varied considerably and included guidance on specific countermeasure selection, providing research citations, training development, teaching, and supporting Road Safety Audits. Each chapter was reported at least once as being the most useful. ■ Those who reported being unable to apply the HFG cited confusion about when it was applicable, lack of training, and not working on projects that require human factors considerations. The least useful reported chapters tended to be early chapters and front matter such as “How to Use This Document.”

6 ■ New topics for inclusion were remarkably consistent between both users and non-users of the HFG. The top four selections for both groups were Pedestrians, Bicycles, Older Road Users, and Roundabouts in that order.  Several users proposed interesting new topics that had not been previously considered, such as sustainability, asphalt and concrete types, and cold weather driving. Overall, the responses seemed to indicate that those who have used the HFG for multiple projects are very satisfied with the quality and applicability of the HFG. Task 5: Conduct Initial Literature Review to Identify Potential Guideline Content A comprehensive literature review was conducted to evaluate the scope of the literature available, to identify promising areas of inquiry for the development of new guidelines, and to identify existing chapters and topics where the body of new literature available indicates the potential for meaningful updates. The general approach to accomplishing this task included the following steps:  Conduct “broad brush” literature search to identify useful data sources  Conduct a review of the abstracts found in the literature search to: o Select key information using the Best Evidence Synthesis (BES) technique1 o Develop initial assessments of the applicability of available information to the HFG  Prioritize the topics and chapters in terms of user interest, available information, age of existing chapters (i.e., when the chapter was developed in earlier HFG efforts), and available schedule and budget. Detailed methods used to conduct the literature searches and review are described in the Task 7 Interim Report. After performing searches on every chapter topic, acquiring the abstracts, and entering those abstracts into our database, there were 33,982 abstracts in the database. To reduce this number to a manageable amount, every duplicate reference, references missing key information such as year or author names, and documents written in non-English languages where translations were not readily available were removed. Sources dated prior to 2010 were also removed from the database. This process left 9,157 abstracts remaining. Once the baseline set of research sources was established, a preliminary review of the abstracts was conducted 1) to identify whether there was sufficient information to create each new chapter or update existing ones, 2) to refine the emphasis of each topic or define new topics based on the focus of the available research, and 3) to identify sources that were expected to contain the most relevant, timely, and useful information for guideline development. In-depth reviews of the abstracts identified as potentially relevant and useful for guideline development were then 1 In the BES approach, data sources representing the best evidence within a topic area are selected for review. Quality and applicability, reflecting different goals and methods across studies, will vary from topic to topic, yet will meet minimum standards. This review type requires the a priori development and application of consistent and well- justified criteria for study selection.

7 conducted to aid in prioritizing the topics, develop annotated outlines for new chapters, and identify sources of interest for updating existing chapters. Once a set of potential sources was identified from the reviews, the potential new HFG chapters and chapter updates (both new and existing) were prioritized using a structured methodology based on four factors: ■ User Needs (from the Task 4 User Survey) ■ Availability of Sources (from the Task 5 Literature Search and Abstract Reviews) ■ Chapter Age (from the creation date of existing chapters) ■ Project Resource Requirements (i.e., expected level of effort, based on the Task 5 Literature Search and Abstract Reviews) Figure 2 illustrates the chapter prioritization process. The full methodology used for prioritizing the chapters is found in the Task 7 Interim Report. Figure 2. Chapter prioritization process. Summary of Search Results, Abstract Review, and Prioritization The literature search yielded 9,157 potentially useful abstracts to be reviewed. After initial review of these abstracts, 7,721 were found to be of little utility during the preliminary abstract reviews; these were removed from further consideration, leaving 1,436 abstracts for more in- depth review while developing the annotated outlines and preparing summaries of existing chapter updates in Task 6. Detailed outcomes of the search results, including the initial number of sources found, the number of abstracts included in the preliminary review, and the number of abstracts found potentially applicable to the HFG3, are found in the Task 7 Interim Report.

8 Table 1 presents the results of the topic prioritization activity. Table 1. Prioritized candidate new chapters and existing topic updates. Chapter Title High Priority Medium Priority Low Priority New Bicyclists New Pedestrians New Roundabouts New Road Diet/Complete Streets New Older Road Users 2 New Motorcycles New Transit New Heavy Vehicles New Connected/Automated Vehicles 1 Why Have Human Factors Guidelines for Road Systems? 2 How to Use This Document 3 Finding Information Like a Road User 4 Integrating Road User, Highway Design, and Traffic Engineering Needs 5 Sight Distance 6 Curves (Horizontal Alignment) 7 Grades (Vertical Alignment) 8 Tangent Sections and Roadside (Cross Section) 9 Transition Zones Between Varying Road Designs 10 Non-Signalized Intersections 11 Signalized Intersections 12 Interchanges 13 Construction and Work Zones 14 Rail-Highway Grade Crossings 15 Special Considerations for Urban Environments 16 Special Considerations for Rural Environments 17 Speed Perception, Speed Choice, and Speed Control 18 Signing 19 Changeable Message Signs 20 Markings 2 This new information will likely be included as updates to existing chapters and components of some new chapters rather than as a stand-alone chapter.

9 Chapter Title High Priority Medium Priority Low Priority 21 Lighting New Tutorial - Summary of HFG Topics New Tutorial - Using the HFG to Support Road Safety Audits New Tutorial - Using the HFG to Conduct Diagnostic Assessments of Safety Concerns New Tutorial - Joint Use of the HFG and the HSM