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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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Suggested Citation:"Chapter 3 - Survey Results." National Academies of Sciences, Engineering, and Medicine. 2021. Temporary Pavement Markings Placement and Removal Practices in Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/26358.
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37   Survey Results A survey was developed and administered to gain greater understanding of the state of the practice for temporary pavement markings in work zones and pavement marking removal in the United States. e survey was reviewed by the topic panel before being sent to each DOT via Qualtrics Survey Soware (Qualtrics 2020). Responses were received from all 50 states and the District of Columbia, for a 100% response rate. e contact list for the survey was developed based on information obtained from FHWA. Although the survey was sent to one respondent from each DOT, respondents were encouraged to collaborate with others at their DOT and to forward the survey to the sta who would be most capable of answering the questions and providing the most accurate information. Survey questions asked specically about seven types of temporary pavement markings (epoxy, preformed plastic, temporary tape, thermoplastic, paint, buttons, and tabs) and seven methods for pavement marking removal (grinding, sandblasting, shot blasting, water blasting, milling, black tape, and slurry seal). Each question asking about these specic marking types and removal methods also included an “other” option with space for respondents to provide information about marking types and removal methods not listed on the survey. Topics for temporary pavement markings and pavement-marking removal methods that were covered by the survey include frequency of use, performance, factors considered, policies and guidance, basis of payment, and percentage of pavement by type. A copy of the full survey can be found in Appendix A, a list of responding DOTs is shown in Appendix B, and the survey responses including comments and resources submitted are shown in Appendix C. is chapter is organized into the following sections: Experience with Temporary Pavement Markings (survey Questions 1 to 3, 7, and 9); Experience with Pavement Marking Removal (survey Questions 4 to 6, 8, and 10); Policies, Procedures, and Specications (survey Questions 11 to 13); Performance Evaluations (survey Question 14); Pavement Type (survey Question 15); and Other Survey Feedback (survey Questions 16, 17). Experience with Temporary Pavement Markings Use of Temporary Pavement Markings Questions 1 to 3 of the survey sought information regarding the frequency of use for dierent types of temporary pavement markings in work zones for intermediate surfaces of asphalt pavement, nal surfaces of asphalt pavement (prior to placement of permanent markings), and concrete pavement. As shown in Figure 29 through Figure 31, paint is the most commonly used type of temporary pavement marking for all three pavement surface types. Paint is always or almost always applied by 81% of DOTs for intermediate surfaces of asphalt pavement, 63% of DOTs for nal surfaces of asphalt pavement, and 53% of DOTs for concrete pavement. C H A P T E R 3

38 Temporary Pavement Markings Placement and Removal Practices in Work Zones Total number of respondents = 51; ordered by Always + Almost Always – high to low Figure 29. Survey results for frequency of use of temporary pavement markings on intermediate surfaces of asphalt pavement. For asphalt pavement, temporary tape and tabs are the second and third most frequently used temporary pavement marking in work zones. For intermediate asphalt surfaces, 92% of DOTs deploy temporary tape to some degree, while 69% of DOTs use tabs. Temporary tape and tabs are applied less oen for nal asphalt surfaces than for intermediate asphalt surfaces, as they are used by 64% and 61% of DOTs on nal asphalt surfaces, respectively. Preformed plastic is rarely used, as 69% of DOTs reported no usage on intermediate asphalt surfaces and 76% of DOTs indicated that they are not applied to nal asphalt surfaces. Other types of markings for asphalt pavement mentioned in the comments include temporary raised retroreective markers, raised pavement markers (RPMs), urethane, polyurea, and foil-backed tape for leveling or base courses. Some DOTs provided additional details regarding conditions when dierent types of mark- ings are used on asphalt pavement. A full list of survey comments for each question may be found in Appendix C. Some of the notable comments are summarized as follows. ID numbers

Survey Results 39   randomly assigned to each DOT are used in lieu of state names to preserve the condentiality of survey comments. • DOT 42 typically applies epoxy for winter months, paint for short-duration projects of less than one summer, and tabs for chip seals. • For temporary markings on nal asphalt surfaces, DOT 14 requires tabs for centerline markings and does not allow paint. • DOT 36 uses waterborne paint for most routes, except that epoxy is applied in the northern part of the state and polyurea is used for divided highways. • DOT 41 is currently testing the performance of surface-applied polyurea at a thinner mil level. For concrete pavement, temporary tape is the second most frequently applied type of temporary pavement marking in work zones, with 78% of DOTs indicating its use to some degree. Several other types of temporary markings are implemented less oen. Buttons, tabs, Figure 30. Survey results for frequency of use of temporary pavement markings on nal surfaces of asphalt pavement. Total number of respondents = 51; ordered by Always + Almost Always – high to low

40 Temporary Pavement Markings Placement and Removal Practices in Work Zones epoxy, thermoplastic, and preformed plastic are all used with a frequency of sometimes, always, or almost always by 20% or more of DOTs. On the other hand, 71% of DOTs do not use preformed plastic for temporary markings on concrete. Other types of temporary pavement markings for concrete pavements listed in the comments include Class W tape, urethane, polyurea, and contrast markings. Four DOTs reported that they do not have concrete pavement. Noteworthy comments are summarized in the following list. • DOT 40 requires the use of temporary tape when the marking crosses a permanent surface at an angle. • DOT 30 typically places paint or temporary tape, but a durable liquid such as epoxy is applied for temporary markings le in place during winter months. • DOT 14 normally uses buttons or temporary tape for concrete, with paint used to paint white over the existing median yellow edge line for temporary two-way trac operations on multilane highways. • DOT 23 applies contrast marking on rare occasions on bridge decks. Figure 31. Survey results for frequency of use of temporary pavement markings on concrete pavement. Total number of respondents = 51; ordered by Always + Almost Always – high to low

Survey Results 41   Maps showing the geographic distribution of answers by state for paint, temporary tape, and tabs for the nal surface of asphalt pavement and paint, temporary tape, and buttons for concrete pavement are shown in Figure 32 through Figure 37. Some general trends on the maps can be observed. For nal asphalt surfaces, paint is more predominantly applied on nal asphalt surfaces in Western and Southeastern DOTs, while the use of temporary tape is more prevalent in Western and Midwestern DOTs. Tabs tend to be used more frequently in Western DOTs, while they are applied less oen in Midwestern and Southeastern DOTs. For concrete pave- ment, paint is more frequently used in Western and North Central DOTs. e application of temporary tape is distributed throughout all regions of the United States, and buttons are more frequently implemented in Western DOTs. To assess potential impacts of climate on the frequency use of temporary pavement markings, the states were grouped into climate regions from the National Oceanic and Atmospheric Administration (NOAA) as shown in Figure 38. For purposes of analysis, Alaska was assigned to the Northwest region, Hawaii was assigned to the West region, and the District of Columbia was assigned to the Northeast region. Figure 39 shows the survey results for average frequency of use for paint, temporary tape, and tabs by region along with the average frequency of use for all DOTs. Some general trends can be observed in Figure 39. For example, paint is used more frequently in the Southwest, East North Central, and Central regions and less frequently in the Northwest, West, and West North Central regions. Temporary tape is used more frequently in the West and Northwest regions, while tabs are used more frequently in the Northwest, South, Southwest, and West regions. Additional statistics for the frequency of use of all types of temporary pavement markings included in the survey are provided in Appendix G. Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 32. Map showing frequency of use of paint on nal surfaces of asphalt pavement by DOTs.

42 Temporary Pavement Markings Placement and Removal Practices in Work Zones Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 33. Map showing frequency of use of temporary tape on nal surfaces of asphalt pavement by DOTs. Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 34. Map showing frequency of use of tab markings on nal surfaces of asphalt pavement by DOTs.

Survey Results 43   Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 35. Map showing frequency of use of paint on concrete pavement by DOTs. Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 36. Map showing frequency of use of temporary tape on concrete pavement by DOTs.

44 Temporary Pavement Markings Placement and Removal Practices in Work Zones Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 37. Map showing frequency of use of buttons on concrete pavement by DOTs. Source: NOAA n.d. Figure 38. Climate regions of the continental United States.

Survey Results 45   Selection of Temporary Pavement-Marking Material In Question 9, respondents were asked how frequently various factors were considered when selecting types of temporary pavement markings for a work zone on a given project. e results, shown in Table 8, are sorted by the sum of the percentage of responses for “always” and “almost always.” e results show that the factors most commonly considered are duration for the marking to remain in place, past experience, and safety. Duration is evaluated to some extent by all DOTs. e following factors are always or almost always considered by at least half of the DOTs: duration, past experience, safety, durability, pavement type, retroreectivity, material quality, temperature at time of placement, and cost. is result shows that DOTs take a wide range of considerations into account when selecting temporary pavement markings for work zones. At the other end of the spectrum, provisions for CAVs are rarely or never considered by 80% of DOTs when selecting temporary pavement markings for work zones. Additional infor- mation from the DOT comments is provided in the following list. • DOT 36 is starting to look at considerations for autonomous vehicles. • Both DOT 36 and DOT 23 are considering quality requirements for wet retroreectivity. • DOT 41 expects to assess various factors in greater detail as it moves toward comparing the performance of polyurea and temporary paint. Performance of Temporary Pavement Markings Respondents were asked to rate the performance of temporary pavement markings on a scale of 1 (poor) to 10 (outstanding). e results for intermediate asphalt surfaces, nal asphalt surfaces, and concrete are shown in Table 9, Table 10, and Table 11, respectively. For asphalt pavements, the following temporary marking types were rated as 7 or higher for both inter- mediate and asphalt surfaces: thermoplastic, epoxy, and paint. Tabs received the lowest ratings of 5.26 and 5.55 for intermediate and nal asphalt surfaces, respectively. ere was a high degree of variability in the ratings as the scores ranged from 1 to 10. For concrete pavements, epoxy 5 = Always, 4 = Almost Always, 3 = Sometimes, 2 = Rarely, 1 = Never Figure 39. Survey results for average frequency of use of paint, temporary tape, and tabs by climate region.

46 Temporary Pavement Markings Placement and Removal Practices in Work Zones Q9: How often does your agency consider the following factors when selecting types of temporary pavement markings in a work zone for a given project? Factor Always Almost Always Sometimes Rarely Never No Response Duration for Marking to Remain in Place 33% 43% 24% 0% 0% 0% Past Experience 27% 49% 16% 4% 2% 2% Safety 35% 41% 14% 4% 2% 4% Durability 25% 47% 22% 4% 0% 2% Pavement Type 27% 39% 12% 10% 8% 4% Retroreflectivity 31% 33% 24% 6% 4% 2% Material Quality 22% 39% 25% 6% 4% 4% Temperature at Time of Placement 24% 37% 27% 4% 6% 2% Cost 25% 29% 29% 12% 0% 4% Ease of Removal 16% 31% 37% 10% 6% 0% Weather Effects 22% 18% 35% 18% 6% 2% Ease of Placement 10% 24% 49% 16% 0% 2% Traffic Counts 10% 24% 37% 18% 10% 2% Wet Retroreflectivity 10% 22% 24% 27% 16% 2% Connected and Autonomous Vehicles 0% 4% 14% 25% 55% 2% Other 0% 0% 0% 2% 20% 78% NOTE: Sort order = Always + Almost Always (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 8. Factors inuencing selection of temporary pavement markings.

Survey Results 47   Q7. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = na), how would you rate the performance of each of the following types of temporary pavement markings for each of the three pavement surface types shown in the table below (Asphalt - Intermediate)? Material Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings > 0 Total Responses (including na) Thermoplastic 8.00 2.37 1 10 17 41 Epoxy 7.72 1.90 4 10 18 41 Other 7.50 3.54 5 10 2 14 Traffic Paint 7.00 1.81 2 10 43 46 Preformed Plastic 6.85 2.97 1 10 13 41 Buttons 6.38 2.63 1 10 13 39 Temporary Tape 6.22 1.90 2 10 37 45 Tabs 5.26 1.77 2 8 27 43 NOTE: Sort order = Average Rating (high to low); cell shading based on score increments of 2; total number of respondents = 51; na = not applicable. Table 9. Performance of temporary pavement markings for intermediate asphalt surfaces. Q7. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = na), how would you rate the performance of each of the following types of temporary pavement markings for each of the three pavement surface types shown in the table below (Asphalt - Surface)? Material Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings > 0 Total Responses (including na) Thermoplastic 7.73 2.93 1 10 22 42 Epoxy 7.42 2.29 1 10 19 42 Traffic Paint 7.02 1.77 3 10 42 45 Preformed Plastic 6.93 3.15 1 10 15 42 Other 6.67 2.89 5 10 3 14 Buttons 6.60 2.50 1 10 15 39 Temporary Tape 6.15 1.88 1 9 41 44 Tabs 5.55 1.82 2 8 29 43 NOTE: Sort order = Average Rating (high to low); cell shading based on score increments of 2; total number of respondents = 51; na = not applicable. Table 10. Performance of temporary pavement markings for nal asphalt surfaces.

48 Temporary Pavement Markings Placement and Removal Practices in Work Zones was the only type of temporary pavement marking to receive a score of at least 7. Tabs, tempo- rary tape, and other all received average scores less than 6. Performance ratings for concrete also ranged from 1 to 10. Additional details on performance provided through comments include the following: • DOT 19 nds that there are advantages and disadvantages for all of the various marking types under dierent conditions. • DOT 32 encounters similar performance with urethane, polyurea markings, and epoxy markings. • In the experience of DOT 42, temporary tape peels up on some surfaces. • Based on preliminary testing, DOT 41 is nding that a thin mil application of surface-applied polyurea is performing well and providing more durability than traditional paint. Experience with Pavement Marking Removal Methods for Pavement Marking Removal Questions 4 to 6 of the survey asked respondents about the frequency of use for dierent types of marking removal methods in work zones for intermediate surfaces of asphalt pave- ment, nal surfaces of asphalt pavement (prior to placement of permanent markings), and concrete pavement. As shown in Figure 40 through Figure 42, grinding and water blasting are the most oen used methods for pavement marking removal on all three pavement surface types. For asphalt pavements, grinding is used by 88% and 82% of DOTs for intermediate and nal surfaces, respectively. For concrete pavements, 80% of DOTs use grinding while 82% of Q7. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = na), how would you rate the performance of each of the following types of temporary pavement markings for each of the three pavement surface types shown in the table below (Concrete)? Material Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings > 0 Total Responses (including na) Epoxy 7.26 2.51 1 10 19 42 Thermoplastic 6.89 3.00 1 10 19 42 Preformed Plastic 6.67 2.87 1 10 15 41 Buttons 6.60 2.47 1 10 15 39 Traffic Paint 6.18 2.05 1 10 40 45 Tabs 5.95 1.82 3 8 20 43 Temporary Tape 5.67 2.03 1 8 39 44 Other 2.50 2.12 1 4 2 14 NOTE: Sort order = Average Rating (high to low); cell shading based on score increments of 2; total number of respondents = 51; na = not applicable. Table 11. Performance of temporary pavement markings for concrete surfaces.

Survey Results 49   DOTs apply water blasting. e frequency of use of grinding and water blasting for concrete pavement is comparable for all frequency levels. Slurry seal is only applied by 26% and 12% of DOTs for intermediate and nal asphalt surfaces, respectively. Black tape is implemented with greater frequency on nal surfaces of asphalt pavement than on intermediate surfaces. For concrete pavement, black tape, milling, and slurry seal are the least frequently used methods. Approximately two-thirds of DOTs do not apply black tape to concrete pavements. Other methods described in the comments include blackout paint, pattern masking, and a foil-backed tape on intermediate lis. Noteworthy comments submitted by DOTs regarding pavement-marking removal methods are summarized in the following list. • DOT 32, DOT 14, and DOT 42 typically do not remove markings on intermediate asphalt layers, as these layers are removed or paved over with the next li of asphalt. • DOT 41 sometimes covers existing markings when implementing transition markings on lane shis. Total number of respondents = 51; ordered by Always + Almost Always – high to low Figure 40. Survey results for frequency of use of pavement-marking removal methods on intermediate surfaces of asphalt pavement.

50 Temporary Pavement Markings Placement and Removal Practices in Work Zones • DOT 43, DOT 24, and DOT 46 sometimes apply blackout paint to cover existing markings. • DOT 23 requires that blackout tape must be removed or replied within 15 days of the initial installation. • DOT 50 is transitioning to water blasting. • DOT 26 and DOT 29 try to avoid pavement marking removal on nal asphalt surfaces. DOT 29 applies temporary markings in the same location as permanent markings on nal asphalt surfaces. • DOT 30 typically does not apply black tape on asphalt pavement on east–west routes because the state has found that it reects back in a manner similar to white markings during twilight hours. In addition, DOT 30 does not allow black tape on concrete pavement. • On concrete pavement and areas not receiving an overlay, DOT 27 applies a combination of grinding and water blasting or shot blasting. Maps showing the geographic distribution of answers by state for grinding, water blasting, and black tape for the nal surface of asphalt pavement and grinding, water blasting, and Total number of respondents = 51; ordered by Always + Almost Always – high to low Figure 41. Survey results for frequency of use of pavement-marking removal methods on nal surfaces of asphalt pavement.

Survey Results 51   Total number of respondents = 51; ordered by Always + Almost Always – high to low Figure 42. Survey results for frequency of use of pavement-marking removal methods on concrete pavement. sandblasting for concrete pavement are shown in Figure 43 through Figure 48. For the nal surfaces of asphalt pavement, the maps indicate that grinding is used more frequently in the Midwest. In addition, water blasting is implemented more frequently in the Southwestern DOTs, and black tape is applied more frequently in the Pacic Coast DOTs. For concrete pavement, grinding is more frequently used in the Midwestern DOTs. Water blasting is generally used less frequently in Northwestern and Northeastern DOTs. e implementation of sandblasting is distributed throughout various regions of the United States, with less frequent use in the Northwestern and Upper Midwestern DOTs. e states were again grouped into climate regions from NOAA as shown previously in Figure 38. e results (Figure 49) show that grinding is used more frequently in the East North Central and West North Central regions, while water blasting is used more frequently in the Southwest and West regions. Additional statistics for the frequency of use of all pavement- marking removal methods included in the survey are provided in Appendix G.

52 Temporary Pavement Markings Placement and Removal Practices in Work Zones Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 43. Map showing frequency of use of grinding on nal surfaces of asphalt pavement by DOTs. Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 44. Map showing frequency of use of water blasting on nal surfaces of asphalt pavement by DOTs.

Survey Results 53   Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 45. Map showing frequency of use of black tape on nal surfaces of asphalt pavement by DOTs. Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 46. Map showing frequency of use of grinding on concrete pavement by DOTs.

54 Temporary Pavement Markings Placement and Removal Practices in Work Zones Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 47. Map showing frequency of use of water blasting on concrete pavement by DOTs. Map created with mapchart.net© No Response Never Rarely Sometimes Almost Always Always Figure 48. Map showing frequency of use of sandblasting on concrete pavement by DOTs.

Survey Results 55   In addition to evaluating the application of pavement-marking removal methods by climate region, an analysis of the frequency of implementation of pavement-marking removal methods based on the use of paint, tabs, and temporary tape was performed. e results for grinding, water blasting, and black tape are shown in Figure 50 through Figure 52. e results show that water blasting tends to be used more oen with frequent application of paint. In addition, frequent use of black tape is associated with rare application of paint, indicating that black tape is typically used to cover other types of pavement markings. ere are no apparent clear trends for tabs, and less frequent use of grinding is associated with more frequent application of temporary tape. Additional details regarding this analysis may be found in Appendix H. Selection of Pavement-Marking Removal Methods In Question 10, respondents were asked how frequently various factors were considered when selecting methods to remove or cover existing pavement markings for a work zone on a given project. As shown in Table 12, past experience, pavement scarring, and pavement type are the most frequently considered factors. All DOTs take pavement scarring, which can generate signicant contrast in pavement color or texture and potentially cause driver confusion, into account to some extent, while 96% of DOTs base their selection on past experience. Although the factors included in the question are assessed by most DOTs to some degree, equipment availability and trac counts are taken into account less frequently than the other factors. While approximately one-third of respondents always or almost always consider trac counts, only 14% percent of DOTs do not factor trac counts into the process of selecting a method to cover or remove existing pavement markings. DOT 41 only species the marking removal method for some high-prole projects with more developed construction phasing plans, while DOT 17 nds that safety is linked to ghost markings. Performance of Pavement-Marking Removal Methods In Question 8, respondents were asked to rate the performance of pavement-marking removal methods on a scale of 1 (poor) to 10 (outstanding). e results for intermediate asphalt 5 = Always, 4 = Almost Always, 3 = Sometimes, 2 = Rarely, 1 = Never Figure 49. Survey results for average frequency of use of grinding, water blasting, and black tape by climate region.

56 Temporary Pavement Markings Placement and Removal Practices in Work Zones 5 = Always, 4 = Almost Always, 3 = Sometimes, 2 = Rarely, 1 = Never Figure 50. Survey results for average frequency of use of grinding, water blasting, and black tape based on frequency of use of paint. 5 = Always, 4 = Almost Always, 3 = Sometimes, 2 = Rarely, 1 = Never Figure 51. Survey results for average frequency of use of grinding, water blasting, and black tape based on frequency of use of tabs.

Survey Results 57   5 = Always, 4 = Almost Always, 3 = Sometimes, 2 = Rarely, 1 = Never Figure 52. Survey results for average frequency of use of grinding, water blasting, and black tape based on frequency of use of temporary tape. Q10: How often does your agency consider the following factors when selecting a method to remove or cover existing pavement markings on a given project? Factor Always AlmostAlways Sometimes Rarely Never No Response Past Experience 24% 53% 20% 0% 4% 0% Pavement Scarring 33% 37% 25% 4% 0% 0% Pavement Type 35% 33% 12% 10% 8% 2% Safety 35% 31% 24% 8% 0% 2% Duration 22% 41% 22% 8% 8% 0% Marking Type 22% 41% 20% 12% 4% 2% Ease of Removal 24% 37% 27% 6% 6% 0% Ghost Markings 25% 31% 27% 10% 4% 2% Cost 18% 31% 35% 12% 4% 0% Environmental Concerns 8% 33% 22% 27% 8% 2% Weather Conditions 16% 22% 35% 16% 10% 2% Equipment Availability 18% 18% 39% 16% 6% 4% Traffic Counts 10% 22% 37% 16% 14% 2% Other 0% 0% 0% 0% 18% 82% NOTE: Sort order = Always + Almost Always (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 12. Factors inuencing selection of pavement-marking removal methods.

58 Temporary Pavement Markings Placement and Removal Practices in Work Zones Q8. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = na), how would you rate the performance of each of the following methods to remove or cover existing pavement markings for each of the three pavement surface types shown in the table below (Asphalt - Intermediate)? Method Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings > 0 Total Responses (including na) Other 10.00 na 10 10 1 14 Milling 7.64 2.15 1 10 28 43 Water Blasting 7.38 1.71 4 10 37 46 Grinding 7.09 1.92 2 10 43 47 Shot Blasting 7.09 1.57 4 10 22 40 Sandblasting 6.70 1.44 4 10 27 42 Black Tape 5.32 2.60 1 9 28 44 Slurry Seal 5.00 2.41 1 10 11 38 NOTE: Sort order = Average Rating (high to low); cell shading based on score increments of 2; total number of respondents = 51; na = not applicable. Table 13. Performance of pavement-marking removal methods for intermediate asphalt surfaces. surfaces, nal asphalt surfaces, and concrete are shown in Table 13, Table 14, and Table 15, respectively. Milling and water blasting received the highest average ratings for intermediate asphalt surfaces, while water blasting and shot blasting were rated the highest for nal asphalt surfaces and concrete pavement. For concrete pavement, grinding also scored lower than shot blasting. e performance of black tape and slurry seal was rated the lowest by respondents, with average ratings less than 6 for all three pavement surface types. ere was a lot of variation in the ratings as the scores ranged from 1 to 10. Some challenges with various pavement-marking removal methods based on DOT experi- ence were noted in the comments, as shown in the following list. • DOT 26 and DOT 7 nd that all methods lead to some pavement scarring. • In the experience of DOT 26, tape is less eective during nighttime. • DOT 43 obtains good results with milling but rarely uses it because of concerns about high cost. • DOT 41 has encountered problems with black tape remaining in place. • DOT 13 nds that grinding of thermoplastic lines on older asphalt pavement leads to grooving of the pavement. In the experience of DOT 13 with marking removal on concrete pavement, water blasting causes discoloration, and temporary tape results in a black adhe- sive residue. Policies, Procedures, and Specications Questions 11, 12, and 13 of the survey sought information regarding various aspects of DOT policies, procedures, and specications. In response to these questions, various DOTs submitted resources for specications, TTC plans, guidelines, and other documents as

Survey Results 59   Q8. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = na), how would you rate the performance of each of the following methods to remove or cover existing pavement markings for each of the three pavement surface types shown in the table below (Asphalt - Surface)? Method Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings > 0 Total Responses (including na) Other 8.00 2.83 6 10 2 14 Water Blasting 7.15 1.94 2 10 40 47 Shot Blasting 6.76 1.76 4 10 21 40 Grinding 6.50 2.26 1 10 44 48 Milling 6.41 2.75 1 10 27 42 Sandblasting 6.31 1.64 2 10 26 42 Black Tape 5.60 2.43 1 9 30 44 Slurry Seal 4.60 3.27 1 10 10 38 NOTE: Sort order = Average Rating (high to low); cell shading based on score increments of 2; total number of respondents = 51; na = not applicable. Table 14. Performance of pavement-marking removal methods for nal asphalt surfaces. Q8. On a scale of 1 to 10 (1 = Poor, 10 = Outstanding, 0 = na), how would you rate the performance of each of the following methods to remove or cover existing pavement markings for each of the three pavement surface types shown in the table below (Concrete)? Method Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings > 0 Total Responses (including na) Water Blasting 7.41 1.83 3 10 41 47 Shot Blasting 7.09 1.77 3 10 22 40 Sandblasting 6.70 1.77 3 10 27 42 Grinding 6.32 2.54 1 10 38 48 Milling 6.00 3.31 1 10 22 41 Black Tape 4.72 2.89 1 9 18 44 Slurry Seal 2.00 1.55 1 5 6 38 Other 1.00 na 1 1 1 15 NOTE: Sort order = Average Rating (high to low); cell shading based on score increments of 2; total number of respondents = 51; na = not applicable. Table 15. Performance of pavement-marking removal methods for concrete surfaces.

60 Temporary Pavement Markings Placement and Removal Practices in Work Zones summarized in Appendix C. e results for Question 11 in Table 16 indicate that 39% of DOTs have a documented process or criteria for the selection of types of temporary pave- ment markings or methods to remove or cover existing pavement markings in work zones on a given project. Noteworthy comments are synthesized in the following list: • DOT 47 provides options in its specications but typically allows the contractor to make the decision. • DOT 43 typically applies engineering judgment based on experience. • DOT 26 is developing an implementation plan for the use of polyurea instead of paint for some situations, with cost being an important consideration. Question 12 of the survey asked respondents if they have used or developed any docu- mented policies, procedures, specications, standards, or guidelines for various topics related to temporary pavement markings and pavement marking removal. As shown in Table 17, at least half of the DOTs have used or developed such documentation for TTC requirements, minimum quality requirements, timeline requirements, design requirements, and monitoring and inspection. Only 35% of DOTs have used or developed warrants for temporary pavement markings. In the comments, DOT 28 noted the use of its typical trac control standards for temporary pavement markings and pavement marking removal. Table 18 shows the results for Question 13 regarding typical methods (measured pay item, lump-sum pay item, or no direct payment) for basis of payment for the installation and mainte- nance of temporary pavement markings and pavement marking removal. Measured pay item is most frequently used for installing temporary pavement markings and pavement marking removal by 86% and 73% of DOTs, respectively. Only 43% of DOTs measure maintenance of temporary pavement markings for payment, while 45% do not make direct payment for the contractor to maintain temporary pavement markings. Notable comments are shown in the following list. • DOT 42 includes the cost of pavement marking removal in the pay item for temporary pavement markings. • For DOT 38, removal of pavement markings can be measured for payment or incidental for trac control. • DOT 43 only pays for maintenance of temporary pavement markings in some instances. Performance Evaluations e results for Question 14, shown in Table 19, demonstrate that only 16% of DOTs have completed performance evaluations for temporary pavement markings or pavement-marking removal methods. DOT 43 and DOT 7 indicated that while performance evaluations may have Q11: Does your agency have a documented process or criteria for the selection of types of temporary pavement markings or methods to remove or cover existing pavement markings in work zones on a given project? Yes 39% No 59% No Response 2% NOTE: Total number of respondents = 51. Table 16. Documented processes or criteria for selection of temporary pavement markings and marking removal methods.

Survey Results 61   Q12: Has your agency used or developed any documented policies, procedures, specifications, standards, or guidelines for the following topics related to installation of temporary pavement markings and pavement marking removal in work zones? Topic Yes No No Response Temporary Traffic Control Requirements 71% 25% 4% Minimum Quality Requirements (e.g., color, retroreflectivity) 67% 29% 4% Timeline Requirements 61% 35% 4% Design Requirements 55% 37% 8% Monitoring and Inspection 51% 43% 6% Maintenance Requirements 45% 49% 6% Abbreviated Pavement Marking Patterns 43% 51% 6% Thresholds for Acceptance of Pavement Removal 39% 55% 6% Warrants for Temporary Pavement Markings 35% 59% 6% Other (please describe in comments box below) 2% 25% 73% NOTE: Total number of respondents = 51. Table 17. Use of agency policies and standards for temporary pavement markings and marking removal by topic. Q13: For each of the work zone activities below, what method does your agency use most frequently as basis of payment? Activity Measured Pay Item Lump Sum Pay Item No Direct Payment Other No Response Installation of Temporary Pavement Markings 86% 8% 6% 0% 0% Maintenance of Temporary Pavement Markings 43% 10% 45% 2% 0% Removal of Temporary or Permanent Pavement Markings 73% 8% 16% 4% 0% NOTE: Total number of respondents = 51. Table 18. Typical methods for basis of payment. Q14: Has your agency completed any performance evaluations of temporary pavement markings or methods to remove or cover existing pavement markings in work zones? Yes 16% No 82% No Response 2% NOTE: Total number of respondents = 51. Table 19. Performance evaluations of temporary pavement markings and marking removal methods.

62 Temporary Pavement Markings Placement and Removal Practices in Work Zones been performed, they were not aware of any formal documents for these assessments. DOT 50 primarily uses water blasting for marking removal and nds that it performs well, although con- tractor availability for the water blasting sometimes leads to scheduling challenges. DOT 13 noted in the comments that contractors oen lack the proper equipment for pavement marking removal. Pavement Type In response to Question 15, the results for the average percentage of pavement by type are provided in Table 20. Asphalt is by far the most common pavement type. Pavement types in the “Other” category include gravel, asphalt overlay on concrete, chip seal, cape seal, and microseal. 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 21, 31% of DOTs indicated that they would be interested in participating in a case example. DOTs pro- vided information regarding projects for possible case examples. Open feedback from DOTs can be found in Appendix C, and some notable comments are listed in the following list. • DOT 41 is in the process of assessing alternatives to temporary paint in work zones. • DOT 22 considers project duration to be an important factor when determining which type of temporary pavement marking should be used. • DOT 24 emphasizes the importance of retroreectivity of the markings for nighttime work zones. Q16: Would your agency be interested in participating in a case example? Yes 31% No 67% No Response 2% NOTE: Total number of respondents = 51. Table 21. Number of DOTs willing to participate in a case example. Q15: Please indicate below the estimated percentage of pavement by type for roadways under your agency’s jurisdiction. (You may want to check the HPMS annual report where this information might be available.) Pavement Type Average No Response/Insufficient Data Asphalt 87% 31% Concrete 9% 31% Other 4% 31% NOTE: Total number of respondents = 51. HPMS = Highway Performance Monitoring System. Table 20. Estimated percentages of pavement by type for DOTs.

Survey Results 63   • DOT 23 is interested in learning about innovative solutions for markings that last throughout the winter, avoiding ghost markings with autonomous vehicles becoming a consideration, and removal and installation of rumbles on rumble stripes. Summary of Key Survey Findings Key ndings from the survey are summarized in the following list. • Paint, temporary tape, and tabs are the most frequently used temporary pavement markings on asphalt pavement in work zones. Paint is always or almost always used by 81% of DOTs for intermediate surfaces of asphalt pavement and by 63% of DOTs for nal surfaces of asphalt pavement. Example situations in which temporary tape is used include markings crossing a permanent surface at an angle, TTC phases prior to the nal construction phase, and during winter months. • For concrete pavement, paint and temporary tape are the most frequently applied temporary pavement markings in work zones, with paint implemented always or almost always by 53% of DOTs. • ermoplastic and preformed plastic are the least commonly implemented types of tempo- rary pavement markings for work zones on both asphalt and concrete pavements. • Analysis of the types of temporary pavement markings and marking removal methods used by DOTs shows that there are some tendencies with regard to geographic distribution by climate region of the United States. For example, paint is used more frequently in the Southwest, East North Central, and Central regions, while temporary tape is used more frequently in the West and Northwest regions. Grinding is used more frequently in the East North Central and West North Central regions, while water blasting is used more frequently in the Southwest and West regions. • In selecting temporary pavement markings for work zones, DOTs most frequently consider duration, past experience, and safety, with duration being examined by all DOTs. Duration, past experience, safety, durability, pavement type, retroreectivity, material quality, tempera- ture at time of placement, and cost are always or almost always considered by at least half of the DOTs. • Provisions for CAVs are rarely or never considered by 80% of DOTs when selecting tempo- rary pavement markings for work zones. • ermoplastic and epoxy received the highest DOT performance ratings for both asphalt and concrete pavements, while tabs and temporary tape received the lowest performance ratings. • ere is a great deal of variability in the DOT performance ratings for dierent types of temporary pavement markings and pavement-marking removal methods, suggesting a wide range of DOT experiences. • Grinding and water blasting are the methods for pavement marking removal that are most oen used for intermediate asphalt surfaces, nal asphalt surfaces, and concrete pavement. At least 80% of DOTs apply grinding on both concrete and asphalt pavements. Shot blast- ing, black tape, and slurry seal are the least frequently used methods for removing pavement markings on asphalt and concrete pavements. Concerns raised by DOTs about black tape in the survey comments include an observed tendency to reect light during twilight on east–west routes, reduced performance during nighttime operations, and challenges with the tape not staying in place. • Past experience, pavement scarring, and pavement type are the factors most frequently considered by DOTs in selecting pavement-marking removal methods. Pavement scarring is taken into account by all DOTs.

64 Temporary Pavement Markings Placement and Removal Practices in Work Zones • The pavement-marking removal methods rated the highest by the DOTs are milling and water blasting (asphalt—intermediate pavement) and water blasting and shot blasting (asphalt—surface and concrete pavements). Black tape and slurry seal were rated the lowest by DOTs for both concrete and asphalt pavements. • While fewer than half of the DOTs have documented processes or criteria for selecting types of temporary pavement markings or methods to remove pavement markings, the majority of DOTs have used or developed policies or specifications for the following requirements for temporary pavement markings and pavement marking removal: TTC, minimum quality, timeline, design, and monitoring and inspection. • Measured pay item is typically the basis of payment used by DOTs for installation of tempo- rary pavement markings (86% of DOTs) and pavement marking removal (73% of DOTs). Fewer than half of DOTs measure maintenance of temporary pavement markings for payment. • The availability of DOT performance evaluations of temporary pavement markings and pavement-marking removal methods is very limited, and these evaluations are often not documented. Only eight DOTs have completed performance evaluations for temporary pavement markings or pavement-marking removal methods. • Asphalt is the most prevalent type of pavement used by DOTs.

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Agencies must consider many factors, such as work zone duration and weather conditions, in selecting appropriate pavement marking materials to effectively guide drivers through work zones.

The TRB National Cooperative Highway Research Program's NCHRP Synthesis 574: Temporary Pavement Markings Placement and Removal Practices in Work Zones addresses the need for more knowledge on which different types of temporary markings are suitable for specific conditions.

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