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Alternative Intersection Design and Selection (2020)

Chapter: Chapter 3 - Survey Results

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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2020. Alternative Intersection Design and Selection. Washington, DC: The National Academies Press. doi: 10.17226/25812.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2020. Alternative Intersection Design and Selection. Washington, DC: The National Academies Press. doi: 10.17226/25812.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2020. Alternative Intersection Design and Selection. Washington, DC: The National Academies Press. doi: 10.17226/25812.
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35 Survey Results A survey was developed and administered to gain greater understanding of the state of the practice for alternative intersection design and selection in the United States. The survey was reviewed by the topic panel before being sent to each Department of Transportation (DOT) via Qualtrics Survey Software (Qualtrics 2019). Responses were received from all 51 DOTs for a 100% response rate. The contact list for the survey was based on information obtained from FHWA and membership lists for the AASHTO Committee on Design and AASHTO Committee on Traffic Engineering. Although the survey was sent to one respondent from each state, respondents were encouraged to collaborate with others at their DOT and to forward the survey to the staff who would be most capable of answering the questions and providing the most accurate information. Survey questions asked specifically about roundabouts, superstreets, median U-turns (MUTs), continuous flow intersections (CFIs), single point diamond interchanges (SPDIs), and diverg- ing diamond interchanges (DDIs). Each question also had an “other” option with space for respondents to provide information about additional alternative intersection types. Alternative intersection topics covered by the survey included level of use, performance, factors considered, post-implementation evaluations, policies and guidance, training, tools, agency staffing, and public outreach efforts. A copy of the full survey can be found in Appendix A. A list of respond- ing DOTs is shown in Appendix B, and the survey responses, including comments and resources submitted, are shown in Appendix C. Experience with Alternative Intersections Questions 1 through 4 of the survey sought the following information from each DOT: the number of operational alternative intersections, the number of alternative intersections under consideration, the number of alternative intersections in development, and perceived perfor- mance based on a scale of 1 (poor) to 10 (outstanding). The most prevalent alternative intersection type implemented across the country is the roundabout as seen in Figure 32. Ninety percent of DOTs responded that at least one round- about is operational in their DOT with 20% of DOTs stating there are over fifty operational roundabouts in their DOT. The CFI (also known as displaced left turn, or DLT) is the least implemented alternative intersection type with 75% of DOTs reporting zero CFIs in operation and only 18% of DOTs having one-to-five operational CFIs. Superstreet (also known as J-turn, restricted crossing U-turn, or RCUT, reduced conflict intersection, or RCI, reduced conflict U-turn, and synchronized street) and MUT intersections also had high percentages of DOTs with zero facilities in operation at 57% and 69%, respectively. However, North Carolina reported greater than fifty superstreets in operation, and Michigan reported greater than fifty MUTs in C H A P T E R 3

36 Alternative Intersection Design and Selection operation. Seventy-one percent of DOTs reported having at least one SPDI open and opera- tional, and approximately two-thirds of the DOTs have at least one DDI in operation. Other types of intersections reported include jughandles, continuous green-T intersections (CGTs), quadrant roadway intersections (QRIs), and tight urban diamond interchanges. Figures 33 through 39 show the distribution of answers by state. Figure 40 shows that roundabouts had the highest reported number of facilities under consid- eration, with 90% of DOTs responding that at least one roundabout is under consideration. Figure 32. Question 1 results: number of alternative intersections operational. (Total number of respondents = 51) (Map created with mapchart.net ©) Figure 33. Map of survey results for number of roundabouts open and operational.

Survey Results 37 (Map created with mapchart.net ©) Figure 34. Map of survey results for number of superstreets open and operational. (Map created with mapchart.net ©) Figure 35. Map of survey results for number of MUTs open and operational. (Map created with mapchart.net ©) Figure 36. Map of survey results for number of CFIs open and operational.

38 Alternative Intersection Design and Selection (Map created with mapchart.net ©) Figure 37. Map of survey results for number of SPDIs open and operational. (Map created with mapchart.net ©) Figure 38. Map of survey results for number of DDIs open and operational. (Map created with mapchart.net ©) Figure 39. Map of survey results for number of other alternative intersection types open and operational.

Survey Results 39 (Total number of respondents = 51) Figure 40. Question 2 results: number of alternative intersections under consideration. The results show that DDIs and SPDIs are frequently contemplated, with 82% of DOTs indi cating that they have at least one DDI under consideration and approximately two-thirds of DOTs planning at least one SPDI. Only approximately one-quarter of DOTs reported having at least one CFI under consideration. Twelve percent (12%) of DOTs reported one-to-five other intersection types under consideration, including CGTs, QRIs, bowtie inter sections, reverse superstreet intersections, a double contraflow grade-separated inter- section, echelon interchanges, a mix of a roundabout and DDI, and other hybrid mixes of alternative designs. Roundabouts also had the highest reported number of facilities in project development as 88% of respondents indicated there was at least one roundabout under development at their DOT. In addition, 73% of DOTs reported having at least one DDI being developed. Approxi- mately one-third of DOTs indicated that there was at least one superstreet (also known as J-turn, RCUT, RCI, reduced conflict U-turn, and synchronized street) under development, and 18% of DOTs responded that they are developing at least one MUT. The complete distribu- tion of inter section types under development can be seen in Figure 41. Other intersection types in the project development phase as reported by respondents include ramp terminal roundabouts, a bowtie intersection, quadrant intersections, reverse superstreet intersections, a partial cloverleaf interchange (parclo) B with contraflow left-turns, and several hybrid mixes of alternative forms. The average respondent performance ratings for the intersection types are shown in Table 5, and the distribution of the ratings by the respondents is shown in Figure 42. DDIs, roundabouts, and superstreets were rated the highest for performance by the respondents. North Carolina reported obtaining excellent crash reductions with superstreets. The number of ratings for superstreets is lower than the number of ratings for DDIs and roundabouts, because the number of states with at least one intersection open and operational is lower for superstreets than for DDIs

40 Alternative Intersection Design and Selection (Total number of respondents = 51) Figure 41. Question 3 results: number of alternative intersections in development. Q4. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = N/A), how would you rate the performance of the following intersection/interchange types that have been implemented by your agency? Average Rating Lowest Rating Highest Rating Total Reponses (Including N/A) DDI 8.4 5 10 36 Roundabout 8.3 5 10 49 Superstreet 8.2 5 10 20 SPDI 7.8 5 10 38 MUT 7.4 5 10 18 Other 7.0 5 9 5 CFI 6.3 2 9 19 Note: Sort order = average rating (high to low). Table 5. DOT average performance ratings for alternative intersections. and roundabouts. The other intersection types were also generally rated highly by the respon- dents. Two DOTs reported CGTs with an average rating of 7.0. CFIs received the lowest average rating at 6.3 and were the only alternative intersection type to receive a DOT rating lower than 5. It should be noted that 12 respondents provided a performance rating for CFIs, but only 11 respondents indicated having at least one CFI open and operational in their state. Concerns raised about CFIs in the comments included large right-of-way requirements and signalization challenges. Respondents also mentioned several concerns about SPDIs, including the need for large bridges, construction and maintenance issues, and challenges with accommodating bicyclists and pedestrians. Further analysis was performed using the number of roundabouts as a surrogate measure of level of experience with alternative intersections. Table 6 shows the average performance ratings for the following groups: all DOTs, the 16 DOTs with 10 or fewer roundabouts open and

Survey Results 41 operational (Group A), and the 33 DOTs with more than 10 roundabouts open and operational (Group B). The results show that Group A rated roundabouts slightly lower than Group B and other alternative intersection types higher than Group B. Thus, DOTs with fewer roundabouts generally had a less positive perception of roundabouts than other alternative intersection types, while DOTs with more roundabouts viewed roundabouts slightly more positively than other alternative intersection types. (Total number of respondents = 51) Figure 42. Question 4 results: performance ratings of alternative intersections. All DOTs DOTs with 10 or fewer roundabouts open and operational (Group A) DOTs with more than 10 roundabouts open and operational (Group B) Average Rating Number of Ratings > 0 Average Rating Number of Ratings > 0 Average Rating Number of Ratings > 0 DDI 8.4 33 9.0 9 8.2 24 Roundabout 8.3 48 8.1 14 8.5 33 Superstreet 8.2 18 9.0 2 8.1 16 SPDI 7.8 36 8.8 10 7.5 26 MUT 7.4 14 8.3 3 7.2 11 Other 7.0 2 n/a 0 7.0 2 CFI 6.3 12 9.0 2 5.7 10 Note: Sort order = average rating (high to low for all DOTs). Table 6. Performance ratings, by group, based on number of open and operational roundabouts.

42 Alternative Intersection Design and Selection Considerations for Alternative Intersections The results for the question regarding factors considered in intersection type selection are shown in Table 7. Traffic capacity was the factor most often considered with 78% of DOTs reporting that this factor is always or almost always taken into account. Generally, the major- ity of DOTs responded that they consider each factor always or almost always. Life-cycle cost was the only factor with a significant response rate of “rarely,” with 20% of DOTs reporting it is rarely considered. Other factors provided by the respondents in the comments included the project delivery type, travel time, queuing, design vehicle, corridor context, utilities, environ- mental impacts, economic development, smart growth, aesthetics, reliability, oversized vehicles, and Amish buggies. Georgia responded in the comments that the degree to which the factors are considered depends on project context and the type of project delivery. Responses to the question regarding concerns that can hinder development of alternative intersections can be seen in Table 8. Public opposition and stakeholder concerns are the most reported obstacles to implementing alternative intersections as approximately 85% of DOTs strongly agreed or somewhat agreed that they hinder efforts. Another key finding is that liabil- ity issues and awareness of benefits of alternative intersections do not appear to be limiting concerns as only approximately 15% of respondents agreed or somewhat agreed that these factors hinder implementation of alternative intersections at their DOT. Understaffed agen- cies and proper expertise to design or review had the highest numbers of DOTs strongly dis- agreeing that they caused concern, although those percentages were only around 40%. Other obstacles reported by DOTs included concern with re-routing traffic, cost-effectiveness due to lack of expertise, Maintenance of Traffic (MOT), strong culture for traditional designs, need for consensus internally, political considerations, and considerations for visually impaired users at roundabouts. To assess possible effects of DOT experience with alternative intersections on their percep- tions of implementation challenges, the results for this question were separated into two groups Q5. How frequently would you estimate that your agency considers the following factors when selecting an intersection type at a given site? Always Almost Always Sometimes Rarely Never No Response Capacity 78% 20% 2% 0% 0% 0% Costs (Initial) 73% 25% 2% 0% 0% 0% Right-of-way 75% 20% 6% 0% 0% 0% Access Management 53% 37% 8% 2% 0% 0% Safety Performance 69% 22% 8% 2% 0% 0% Constructability 61% 29% 10% 0% 0% 0% Vehicle Delay 57% 33% 10% 0% 0% 0% Public/Political Reaction 47% 39% 14% 0% 0% 0% Pedestrians 51% 33% 14% 2% 0% 0% Bicyclists 45% 33% 12% 10% 0% 0% Maintenance of Traffic During Construction 51% 27% 16% 6% 0% 0% Vehicle Speed 39% 35% 22% 4% 0% 0% Driver Expectancy 39% 29% 29% 2% 0% 0% Costs (Life-Cycle) 27% 27% 25% 20% 0% 0% Other (Please describe in comments box) 14% 4% 4% 0% 0% 78% Note: Sort order = always + almost always (high to low), cell shading based on 25% increments, total number of respondents = 51. Table 7. Factors considered in alternative intersection selection.

Survey Results 43 Q6. How strongly do you agree or disagree that the following concerns have hindered your agency’s efforts to implement alternative intersection designs? Strongly Agree Somewhat Agree Neither Agree Nor Disagree Somewhat Disagree Strongly Disagree No Response Public Opposition 37% 49% 6% 4% 2% 2% Stakeholder Concerns 25% 59% 8% 6% 0% 2% Public Education 20% 53% 12% 6% 8% 2% Access Management 8% 61% 18% 12% 0% 2% Funding Constraints 20% 43% 25% 6% 2% 4% Newness of Design 16% 47% 12% 12% 12% 2% Large Vehicles 14% 47% 20% 14% 4% 2% Driver Awareness 12% 49% 24% 12% 2% 2% Land Use Constraints 4% 57% 27% 8% 2% 2% Environmental Impacts 6% 45% 27% 16% 4% 2% Operational Impacts 4% 41% 27% 18% 6% 4% Constructability 10% 29% 29% 20% 10% 2% Impacts to Bicyclists and Pedestrians 6% 31% 39% 18% 4% 2% Proper Expertise to Design or Review 8% 29% 18% 20% 22% 4% Agency Understaffed 4% 27% 27% 14% 24% 4% Older Drivers 4% 25% 39% 18% 12% 2% Time to Research and/or Implement 2% 25% 35% 22% 12% 4% Safety Impacts 14% 8% 29% 24% 18% 8% Liability Issues 2% 12% 45% 25% 14% 2% Need Information on Benefits 4% 10% 45% 24% 16% 2% Other (Please describe in comments box) 4% 8% 10% 0% 0% 78% Note: Sort order = strongly agree + somewhat agree (high to low), cell shading based on 25% increments, total number of respondents = 51. Table 8. Concerns hindering efforts to implement alternative intersections. using the number of open and operational roundabouts as a surrogate measure of DOT level of experience with alternative intersections. Results for the 16 DOTs with 10 or fewer open and operational roundabouts (Group A) are shown in Table 9, and results for the 33 DOTs with more than 10 open and operational roundabouts (Group B) are shown in Table 10. In general, the news of the groups are similar. Public opposition was viewed as a hindrance to implementation of alternative intersections by both groups. Liability issues or awareness of benefits were generally not seen as major concerns by participants from both groups. There are also some differences between the two groups. Respondents from Group B viewed stakeholder concerns as more of a challenge than respondents from Group A, with almost 90% of Group B respondents strongly or somewhat agreeing that this factor was a hindrance to implementa- tion of alternative intersections. Impacts to bicyclists and pedestrians, newness of design, and operational impacts were also seen as greater obstacles to alternative intersection implementa- tion by Group B than by Group A. Evaluations of Alternative Intersections Question 7 asked about DOT efforts in evaluating alternative intersections after construc- tion. Forty-nine percent of DOTs reported they had performed evaluations as seen in Table 11. Assessments described by DOTs most often covered roundabouts; however, superstreets, CGTs, DDIs, CFIs, and QRIs have also been evaluated. Many DOTs also responded that eval- uations are informal or anecdotal and not necessarily documented. A complete list of resources submitted by DOTs for this question can be found in Appendix C.

44 Alternative Intersection Design and Selection Policies and Guidance for Alternative Intersections Questions 8 and 9 sought to understand the guidelines or criteria developed by DOTs to aid in the implementation of alternative intersection design. The results in Table 12 show that 37% of DOTs responded they had used or developed documented policies, procedures, or guidelines for inter- section type selection. Six DOTs indicated that they are either developing an Intersection Control Evaluation (ICE) policy or tool or are planning to develop one in the future. Additionally, DOTs reported the use of highway design guides or manuals, the Green Book, Capacity Analysis for Planning of Junctions (CAP-X), FHWA informational guides, or specialty design tools specific to the DOT. Question 9 asked about design criteria, analysis criteria or construction details DOTs may have developed specific to intersection types, and the results are shown in Table 13. Over half of the DOTs reported developing these resources for roundabouts, but fewer DOTs responded that they developed such materials for other intersection types. MUTs and CFIs received the lowest number of “Yes” responses (4%). DOTs also reported the use of specific chapters in their Roadway Design Manual, existing plan sets, and national publications as resources for design criteria. A complete list of resources submitted by DOTs for Questions 8 and 9 can be found in Appendix C. Practices for Alternative Intersections Question 10 concerned training, and the results can be seen in Table 14. Less than one-half of the DOTs responded that they provide training for employees or consultants to evaluate or design intersection types. Roundabout training was the most reported type of training provided Q6. How strongly do you agree or disagree that the following concerns have hindered your agency’s efforts to implement alternative intersection designs? Strongly Agree Somewhat Agree Neither Agree Nor Disagree Somewhat Disagree Strongly Disagree No Response Public Opposition 44% 44% 6% 6% 0% 0% Stakeholder Concerns 31% 44% 19% 6% 0% 0% Public Education 13% 56% 19% 0% 13% 0% Access Management 6% 56% 25% 13% 0% 0% Driver Awareness 13% 50% 25% 6% 6% 0% Environmental Impacts 6% 56% 31% 6% 0% 0% Funding Constraints 19% 44% 31% 6% 0% 0% Large Vehicles 19% 44% 25% 13% 0% 0% Land Use Constraints 6% 50% 31% 6% 6% 0% Newness of Design 6% 50% 13% 13% 19% 0% Constructability 6% 38% 31% 19% 6% 0% Agency Understaffed 0% 38% 38% 6% 19% 0% Proper Expertise to Design or Review 6% 25% 19% 25% 19% 6% Time to Research and/or Implement 0% 31% 38% 25% 6% 0% Impacts to Bicyclists and Pedestrians 6% 19% 50% 19% 6% 0% Operational Impacts 0% 25% 31% 25% 13% 6% Liability Issues 6% 13% 50% 25% 6% 0% Older Drivers 0% 19% 63% 13% 6% 0% Safety Impacts 19% 0% 25% 31% 13% 13% Need Information on Benefits 6% 0% 63% 13% 19% 0% Other (Please describe in comments box) 0% 0% 0% 0% 0% 100% Note: Sort order = strongly agree + somewhat agree (high to low), cell shading based on 25% increments, total number of DOTs reporting 10 or fewer roundabouts open and operational = 16. Table 9. Concerns hindering efforts to implement alternative intersections (DOTs with 10 or fewer roundabouts open and operational – Group A).

Survey Results 45 Q6. How strongly do you agree or disagree that the following concerns have hindered your agency’s efforts to implement alternative intersection designs? Strongly Agree Somewhat Agree Neither Agree Nor Disagree Somewhat Disagree Strongly Disagree No Response Stakeholder Concerns 21% 67% 3% 6% 0% 3% Public Opposition 33% 52% 6% 3% 3% 3% Public Education 24% 48% 9% 9% 6% 3% Access Management 9% 61% 15% 12% 0% 3% Newness of Design 21% 45% 12% 9% 9% 3% Funding Constraints 21% 42% 24% 3% 3% 6% Driver Awareness 12% 48% 21% 15% 0% 3% Land Use Constraints 3% 58% 27% 9% 0% 3% Large Vehicles 12% 48% 18% 12% 6% 3% Operational Impacts 6% 48% 27% 12% 3% 3% Environmental Impacts 6% 39% 27% 18% 6% 3% Impacts to Bicyclists and Pedestrians 3% 39% 36% 15% 3% 3% Proper Expertise to Design or Review 9% 33% 15% 15% 24% 3% Constructability 12% 27% 27% 18% 12% 3% Older Drivers 6% 27% 30% 18% 15% 3% Agency Understaffed 6% 24% 18% 18% 27% 6% Time to Research and/or Implement 3% 24% 33% 18% 15% 6% Safety Impacts 9% 12% 33% 18% 21% 6% Need Information on Benefits 3% 15% 39% 24% 15% 3% Other (Please describe in comments box) 6% 12% 12% 0% 0% 70% Liability Issues 0% 12% 42% 24% 18% 3% Note: Sort order = strongly agree + somewhat agree (high to low), cell shading based on 25% increments, total number of DOTs reporting more than 10 roundabouts open and operational = 33. Table 10. Concerns hindering efforts to implement alternative intersections (DOTs with more than 10 roundabouts open and operational – Group B). Q7. Has your agency performed any evaluations of alternative intersections after construction? Yes 49% No 51% No Response 0% Note: Total number of respondents = 51. Table 11. Number of DOTs performing evaluations of alternative intersections. Q8. Has your agency used or developed any documented policies, procedures, or guidelines for evaluating intersection types and selecting an intersection type for a given site? Yes 37% No 63% No Response 0% Note: Total number of respondents = 51. Table 12. Number of DOTs that have developed policies, procedures, or guidelines for alternative intersections.

46 Alternative Intersection Design and Selection Q9. Has your agency developed any design criteria, analysis criteria, or construction details (including details for signing, marking, and lighting) for the following types of alternative intersections? Yes No No Response Roundabout 59% 35% 6% DDI 20% 73% 8% Superstreet 18% 73% 10% SPDI 12% 76% 12% MUT 4% 86% 10% CFI 4% 84% 12% Other 2% 18% 80% Note: Sort order = yes (high to low), cell shading based on 25% increments, total number of respondents = 51. Table 13. Number of DOTs that have developed design criteria, analysis criteria, or construction details for alternative intersections. Q10. Does your agency provide any training for employees and/or consultants for evaluating and/or designing intersection types for a given site? Yes 45% No 53% No Response 2% Note: Total number of respondents = 51. Table 14. Number of DOTs that provide training for alternative intersections. by DOTs. DOTs offer training from various sources such as FHWA, the National Highway Insti- tute, and internal training. DOTs also indicated in the comments that alternative intersection training is often a subtopic in intersection training, infrequently offered, based on industry or on-the-job training, or provided through online, external sources. The results for Question 11 regarding the development of tools are shown in Table 15. Only 31% of DOTs reported they have developed resources such as software, flowcharts, or work- sheets to assist in the evaluation and selection process of alternative intersection types. Seven DOTs stated they have resources in their ICE policy or they anticipate resources being in their ICE policy that is under development. Other resources mentioned in the comments included CAP-X, safety planning processes, traffic analysis tools, roundabout analysis tools, and concep- tual design procedures. For Question 12 concerning staffing for alternative intersections, roundabouts and DDIs are the intersection types with the most DOTs reporting the use of special in-house engineers or consultants to review projects for those specific intersection types. The majority of DOTs did not have these specialists for other intersection types. Four DOTs reported that they have consultants on contract or on call to peer-review alternative intersection designs. DOTs also Q11. Has your agency developed any resources (e.g., software, flowcharts, worksheets) to assist in the process of evaluating intersection types and selecting an intersection type at a given site? Yes 31% No 69% No Response 0% Note: Total number of respondents = 51. Table 15. Number of DOTs that have developed resources for alternative intersection evaluation and selection.

Survey Results 47 Q12. Does your agency have special in-house engineers or consultants review projects for the following types of alternative intersections/interchanges? Yes No No Response Roundabout 63% 35% 2% DDI 47% 49% 4% SPDI 35% 59% 6% Superstreet 31% 61% 8% CFI 25% 65% 10% MUT 25% 65% 10% Other 8% 6% 86% Note: Sort order = yes (high to low), cell shading based on 25% increments, total number of respondents = 51. Table 16. Number of DOTs using special in-house engineers or consultants to review projects with alternative intersections. Q13. Does/Did your agency have a “champion” for various alternative intersections? (select all that apply) Percent Responding YES, in the traffic department 65% YES, in the highway design department 43% YES, in the senior management level 18% NO, but one is not needed to get alternative intersections selected 24% NO, which makes getting alternative intersections implemented harder 12% No Response 2% Note: Total number of respondents = 51. Table 17. Number of DOTs with champions for alternative intersections. stated that reviews are done internally by committees or teams specific to alternative inter- section design. Virginia has an Innovative Intersection Committee that considers alternative intersections from different perspectives such as design, traffic engineering, land use, plan- ning, access management, safety, and public acceptance. The results for this question are shown in Table 16. Question 13 asked about the existence of a champion for alternative intersections, and respondents were able to choose more than one answer. The results in Table 17 show that most champions are in the traffic department or highway design department. Only 12% of DOTs reported there was no champion, making implementation of alternative intersections harder. DOTs reported in the comments that champions exist in various departments in the central office, district office, traffic safety office, or operations office. Another DOT indicated that advo- cates can be hindered by management opposed to non-traditional designs. One DOT mentioned that its current process is ad hoc, but identification of champions is expected through the ICE policy development. In response to Question 14 regarding resources used for alternative intersection evaluation and selection, the majority of DOTs responded that they always use the Manual on Uniform Traffic Control Devices (MUTCD) and agency standards as shown in Figure 43. Nearly half of the DOTs responded that they always use the Highway Capacity Manual (TRB 2016) and AASHTO Green Book. The majority of DOTs responded that they never use a custom agency software or tool. The results also show that many agencies never use the Safety Performance for Inter section Control Evaluation (SPICE) tool, a worksheet or flowchart, or CAP-X. The Highway Safety Manual (AASHTO 2010) and FHWA Alternative Intersection Guide had dispersed responses

48 Alternative Intersection Design and Selection (Total number of respondents = 51) Figure 43. Question 14 results: types of resources used by DOTs to evaluate and select intersection types. with the majority of DOTs reporting that they are sometimes used. Other resources used by DOTs as described in the comments include VISSIM, Synchro, FHWA resources, a safety infor- mation management system, case studies, NCHRP reports, and the Interactive Highway Safety Design Model. Custom agency tools included ICE tools, roundabout analysis tools, and screen- ing tools based on CAP-X. Public Outreach for Alternative Intersections Question 15 asked about the types of outreach material developed by DOTs to educate and inform the public about alternative intersections, and the results are shown in Table 18. Websites were the most popular form of public outreach with 61% reporting their develop- ment. Videos and flyers/pamphlets were also popular mediums. Approximately one-quarter of respondents indicated that their DOT did not have any public outreach material for alterna- tive intersections. The use of social media appears to be limited, with only 14% of respondents indicating that their DOT used social media for public outreach on alternative intersections. DOTs also mentioned the use of FHWA resources as well as their own YouTube channels.

Survey Results 49 Other Survey Feedback Questions 16 and 17 concluded the survey by inquiring into agencies’ interest in participating in a case example and asking for any other general feedback. As shown in Table 19, 35% of DOTs indi- cated that they would be interested in participating in a case example. DOTs provided information regarding specific intersections of various types for possible case examples. Open feedback from DOTs can be found in Appendix C. Some notable comments included the following: • Use of value engineering and traffic studies during the alternative intersection selection process, • Providing more information about alternative intersections opening in the future, • Explanations for why alternative intersections are hard to implement, • Additional detail regarding the reasons that certain designs are chosen over others, and • Frequent use of roundabouts. Summary of Key Survey Findings The following is a summary of the key findings from the survey. • Roundabouts are the most common alternative intersection type in operation in the United States as 47 DOTs indicated that they have at least one open and operational roundabout. Roundabouts are also under consideration or in the development stage at many DOTs (90% and 88% of DOTs, respectively), followed by DDIs. • CFIs (also known as DLTs) are the least implemented of the alternative intersection types listed in the survey, with 11 DOTs reporting at least one open and operational CFI. Q15. What types of public outreach materials regarding alternative intersections has your agency developed (select all that apply)? Percent Responding My agency has not developed public outreach material for alternative intersections 27% My agency is in the process of developing public outreach material for alternative intersections 20% Website, please provide URL 61% Social media site, please provide URL 14% Flyer and/or pamphlet, please provide URL, upload files, or email files 27% Video, please provide URL, upload files, or email files 39% Other, please specify and provide URL, upload files, or email files 6% My agency uses materials from other agencies, please provide URL, upload files, or email files 14% No response 0% Note: Total number of respondents = 51. Table 18. Number of DOTs that have developed public outreach materials. Q16. Would your agency be interested in participating in a case example? Yes 35% No 63% No Response 2% Note: Total number of respondents = 51. Table 19. Number of DOTs willing to participate in case studies.

50 Alternative Intersection Design and Selection • Some DOTs are not likely to consider SPDIs in the future due to concerns about construc- tion issues and maintenance and preferences for other alternative intersection types. • DOTs are generally satisfied with the performance of the alternative intersections under their jurisdiction. DDIs, roundabouts, and superstreets (also known as J-turns, restricted crossing U-turns, or RCUTs, reduced conflict intersections, or RCIs, reduced conflict U-turns, and synchronized streets) were rated the highest by DOTs. • CFIs were rated the lowest of the alternative intersection types listed in the survey, although that result may be influenced by limited experience with them. • DOTs consider multiple factors in the process of selecting an intersection type, with traffic capacity, right-of-way, and initial costs being the factors most frequently considered. • Public resistance is cited by 86% of DOTs as a major challenge to implementation of alter- native intersections. The public resistance frequently relates to changes in traffic movements or driver behavior or to unfamiliarity with the design. • Other factors frequently seen by DOTs as barriers to implementation include internal resis- tance, access management, driver awareness, land use constraints, large vehicles, and stake- holder concerns. • Most of the available evaluations, design guidance, and training for alternative intersections pertain to roundabouts. Approximately 60% of DOTs have developed design criteria, analysis criteria, or construction details for roundabouts. • Six DOTs indicated that they are either developing an ICE policy or tool or are planning to develop one in the future. • The use of tools for alternative intersection evaluation and selection varies among the DOTs surveyed. The MUTCD, agency standards, HCM, and AASHTO Green Book are the resources most frequently used, while 18% of DOTs use their own evaluation tools at least sometimes. • Less than one-half of the DOTs provide training for employees or consultants on alternative intersections using various sources. • Approximately two-thirds of the DOTs either have champions for alternative intersections or are in the process of identifying these champions. • Almost two-thirds of the DOTs have in-house engineers or consultants review roundabout projects. The use of special in-house staff or consultants to review other alternative inter- section types is less prevalent with the exception of DDIs (47% of DOTs). • Websites are the most commonly used tool (61% of DOTs) for public outreach on alternative intersections. Social media is utilized less frequently (14% of DOTs) for public outreach than other resources. • Public outreach materials from other states (e.g., Missouri or Virginia) or from the FHWA are valuable resources for DOTs.

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State departments of transportation often encounter public resistance to alternative intersections, with 86% of respondents in a new survey of state DOTs agreeing or strongly agreeing that public resistance hinders their implementation. Public resistance can vary among projects based on intersection type and whether the project was initiated at the local or state level.

The TRB National Cooperative Highway Research Program's NCHRP Synthesis 550: Alternative Intersection Design and Selection documents the evaluation and selection processes within state departments of transportation (DOTs) for intersection projects.

Roundabouts are the most widely implemented type of alternative intersection. Ninety percent of state DOTs that responded to the synthesis survey reported having at least one roundabout in their jurisdiction open and operational. Roundabouts also had the highest reported number of facilities in project development as 88% of respondents indicated there was at least one roundabout under development at their DOT.

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