Application of Crash Modification Factors for Access Management, Volume 2: Research Overview (2021)

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165   Introduction This chapter describes the process of organizing and implementing two focus group meetings to solicit feedback from representative members of the target audience on the practitioner guide developed in the NCHRP Project 17-74 research [published as NCHRP Research Report 974: Application of Crash Modification Factors for Access Management—Volume 1: Practitioner’s Guide (Gross et al. 2021)]. The target audience includes transportation professionals with or without prior experience in access management and highway safety (e.g., planners, designers, and traffic engineers). The following two TRB standing committees were targeted to identify representative members of the target audience to serve in the focus group: 1. ACP60: Standing Committee on Access Management (formerly AHB70), and 2. ACS20: Standing Committee on Safety Performance and Analysis (formerly ANB25). The focus group consisted of 40 individuals, which included members of the NCHRP Project 17-74 panel and members and friends of the two TRB committees. Of the 40 individuals, 12 represented state DOTs, three represented local or other public agencies, three represented FHWA, nine represented universities, and 13 represented consultants. Approximately half of the focus group members represented access management professionals and half represented highway safety pro- fessionals. Table 120 provides the agency affiliations of the 31 focus group members that were not NCHRP Project 17-74 panel members. There were two presentations delivered at the 2020 TRB Annual Meeting, one to each of the two targeted committees. These presentations provided background on the objectives and results of NCHRP Project 17-74 as well as the outline and content of the practitioner guide. Following the TRB Annual Meeting, there were two focus group meetings, which are described in the fol- lowing sections. Focus Group Meetings March 2020 Focus Group Meeting The first focus group meeting was held on March 6, 2020. The meeting discussed the focus of the practitioner guide and provided an overview of the layout and content. While reviewing the guide, the project team presented five questions to the focus group for feedback. The questions were the following: • Question 1: Is there a need for a technical brief to summarize salient points of the guide? If so, what content is most important to you? C H A P T E R   9 Focus Group

166 Application of Crash Modification Factors for Access Management • Question 2: Should Chapter 2 remain in the body of the guide or would it be more appropriate in an appendix? • Question 3: Is Figure 10 useful in providing background on observed crashes or is this common knowledge? • Question 4: Is there a need for additional guidance on how to select an appropriate CMF? • Question 5: CMF is relatively large but so is the confidence interval (CMF = 2.12 and St. Err. = 0.91). How do you feel about including such results in the guide? Should we denote with similar cautions provided in the HSM [Highway Safety Manual (1st Edition) (AASHTO 2010)] (observed variability suggests that this strategy could result in an increase, decrease, or no change in crashes)? Following the meeting, focus group members had 3 weeks to review the guide and provide responses to the focus group questions as well as additional feedback on the guide. April 2020 Focus Group Meeting The second focus group meeting was held on April 20, 2020. Nineteen focus group members attended. The meeting provided an overview of the comments received following the first focus group meeting, which are summarized in the following. Question 1: Need for a Technical Brief Overall, the focus group members felt that there was not a need for a technical brief as the information was already known to the reviewers. One focus group member suggested that instead Focus Group Member Affiliations North Carolina DOT New Hampshire DOT DKS Ohio DOT University of South Florida Advanced Transportation Solutions Jacobs Michigan Tech University ITRE Philip B Demosthenes, LLC Texas Transportation Institute WSP Virginia DOT Robert Hull Transportation Safety LLC North Carolina DOT E.L. Robinson Engineering Massachusetts DOT Virginia Tech Transportation Institute Federal Highway Administration Wisconsin DOT Dallas Fort-Worth Airport RKK Burgess and Niple Maricopa Association of Governments HDR Kentucky Transportation Cabinet Auburn University GY Associates (formerly New Jersey DOT) Table 120. Organization affiliations of focus group members (excluding NCHRP Project 17-74 panel members).

Focus Group 167   of creating a technical brief, the project team should develop a one-page infographic explaining the research and how to use it. While the majority of the focus group supported not developing a technical brief, one member shared that the technical brief could be useful for practitioners, following a similar outline as the guide. Another member cautioned that practitioners might look to the technical brief for answers to a question and miss important details that are contained in the full guide. The resolution was to develop an extended summary to serve as a pseudo technical brief. The rationale for the summary was to keep everything in one document while helping readers to understand the key information in just a few pages. Technical audiences would still need to review the relevant chapters of the guide to find details. Question 2: Placement of Chapter 2 The majority of focus group members voted to move Chapter 2 to an appendix to help keep the focus on the main topics in the report. A focus group member suggested the project team could replace Chapter 2 with a definitions page of technical terms and reference the appendix and other resources as appropriate. There was some support to keep Chapter 2 in the body of the guide because the information was important to the target audience. The resolution was to move the Chapter 2 content to Appendix B and replace it with a brief section of definitions. Question 3: Value of Figure 10 The members of the focus group did not come to a consensus regarding the value of Figure 10. Some members indicated the figure should not be included as it provided information already known to the reviewers, while others believed the image should be included as it provided impor- tant information for the target audience. The resolution was to keep the figure in the guide but move it to Appendix B with the other Chapter 2 content. Question 4: Need for Additional Guidance on CMF Selection The focus group supported including additional guidance on how to select an appropriate CMF. The selection process is an important component to properly assessing safety performance, which is why the members felt this information should be included in an appendix. The resolution was to add a section on “Selecting CMFs” to the Chapter 2 content included in Appendix B. Question 5: Including CMF Results That Are Not Statistically Significant The focus group was divided in support for and against including the CMF results with a large confidence interval. Members that supported including the CMF results noted the results were a good educational point, and the project team could denote the results with cautions similar to those provided in the Highway Safety Manual (1st Edition). The members that voted not to include the CMF results believed the results could introduce unnecessary confusion for the reader. If the project team were to include the CMF results, they would need to add language that explained the term “not statistically significant” when the CMF was introduced. The resolution was to keep the CMF results in the guide with proper notations and cautions. Other Comments Members of the focus group provided additional comments beyond the five focus group ques- tions. The focus group discussed several terms included in the guide: CMF star-rating and inclusion

168 Application of Crash Modification Factors for Access Management process, CMF scoring, and calibration of SPFs. The focus group expressed interest in providing some discussion of these items in Appendix B. Another topic of discussion was the functional classification of roads and its relation to access management. Specifically, different functional classifications should have different levels of access and mobility. Members noted that agencies use different definitions of functional classi- fications such as those included in the Highway Functional Classification Concepts, Criteria, and Procedures (U.S.DOT 2013). Related to this discussion, the focus group discussed the term “access point.” The group supported using this term; however, they agreed that the project team should provide additional context when the term is used in the guide. Finally, the focus group provided consistent thoughts on the opportunity to expand the discus- sion in Chapter 6: Communicating Results. One suggestion was to expand Chapter 6 to include more of a communications perspective. Members suggested resources to support this expansion. In summary, the project team revised the practitioner guide to reflect the comments and requests of the focus group. This effort resulted in a more concise presentation of results, more detailed explanation of specific topics of interest, and, hopefully, a more useful guide for practitioners.