Temporary Pavement Markings Placement and Removal Practices in Work Zones (2021)

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5   Introduction Background To navigate safely through work zones, drivers must follow a path through various work zone congurations such as lane changes, alignment shis, and crossovers. e use of temporary pavement markings in work zones helps delineate the vehicle path of travel and direct drivers safely through the work zone. Agencies face many challenges with the placement, main- tenance, and removal of temporary or permanent pavement markings in work zones. For example, agencies must consider many factors, such as work zone duration and weather conditions, in selecting appropriate pavement marking materials for work zones. Drivers may become confused by the markings, especially if they are not familiar with the work zone. Modications to the trac pattern require the eective removal of pavement markings to avoid this confusion and prevent conicts with new temporary or permanent markings. Signicant coordination is oen required to avoid conicts with construction operations. Placement and removal of pavement markings in work zones can cause construction delays and can increase the potential for crashes within the work zones. Advancements in practices for temporary pavement markings and pavement marking removal can help address these chal- lenges and thereby improve work zone operations and safety. Objectives and Scope e objective of the synthesis was to review and document the policies and processes used by state departments of transportation (DOTs) for placement, maintenance, and removal of pavement markings in work zones. e scope of the synthesis included the following topics: • Requirements for temporary trac control (TTC) for placement and removal of pavement markings in work zones; • DOT policies, guidelines, standards, and specications for placement of temporary pavement markings and pavement marking removal; • Design aspects of temporary pavement markings; • Placement and removal of temporary pavement markings on intermediate and nal pave- ment surfaces; • Selection of pavement marking materials and durability considerations for dierent pavement surface types and roadway conditions; • Practices for pavement marking removal for dierent pavement surface types and roadway conditions; • Time considerations for temporary pavement markings; • Minimum requirements for quality of temporary pavement markings (e.g., color, retroreectivity); C H A P T E R 1

6 Temporary Pavement Markings Placement and Removal Practices in Work Zones • Processes for monitoring, inspection, enforcement, and quality assurance of temporary pavement markings in work zones; • Contract basis of payment for maintenance of temporary pavement markings during construction (e.g., lump sum or itemized per application); and • Innovative DOT practices for temporary pavement markings in work zones. Denitions For the purposes of this synthesis, the following denitions are used: • Temporary pavement marking. Any type of material used to delineate the path of travel in a work zone before the placement of permanent pavement markings. • Pavement marking removal. Any method used to eliminate or cover existing pavement markings, including both temporary pavement markings and permanent pavement markings. • Department of transportation (DOT). An agency from the 50 states or District of Columbia that is responsible for the implementation of temporary pavement markings in work zones and the removal of pavement markings. Overview of Temporary Pavement Markings Temporary pavement markings include both striping markings and temporary raised pave- ment markers (TRPMs). Some general characteristics of dierent types of temporary pavement markings are described below (ATSSA 2014). • Paint, also known as trac paint or temporary paint, is a fast-drying liquid with glass beads added for retroreectivity. Types of paint materials for temporary pavement markings include waterborne, polymer-based, low volatile organic compound (VOC), and high build. For the purpose of this synthesis, this denition does not include more durable pavement marking materials such as epoxy, polyurea, or urethane. ese more durable materials are considered as a separate category in this synthesis. • Temporary tape (Figure 1) consists of plastic strips with adhesive on the back and retro- reective material. e tape can be pulled up for removal and is applicable to short-term work zones. Source: Hawkins et al. 2012 Figure 1. Example of temporary tape in work zone.

Introduction 7   • Temporary raised pavement markers (TRPMs), also known as temporary pavement markers (TPMs), are attached to the pavement using an adhesive or peel and stick backing. TRPMs include buttons and tabs (Figure 2). Tabs are plastic strips with a reective strip. Buttons are rounded domes which are less resistant to impacts than tabs. • Epoxy, methyl methacrylate, polyurea, preformed plastic, thermoplastic, and urethane are more durable materials that are sometimes used in long-term work zones. Additional information regarding the dierent types of pavement marking materials, including costs and pros and cons, are shown below in Table 1. Paint, tabs, and buttons have the advantage of lower cost, while thermoplastic and epoxy provide more durability at increased cost. Unpublished average-bid-price data provided by Massachusetts DOT indicates that temporary tape costs four to ve times more than temporary paint. Data from a 5-year averaged price list from the Vermont Agency of Transportation (Table 2) also show that temporary tape is more expensive than temporary tape, and there are only minor dierences in costs for 4-in. and 6-in. markings. (Vermont Agency of Transportation 2020). Overview of Pavement-Marking Removal Methods e synthesis includes all methods of pavement marking removal meeting the denition in the previous section. An overview of several methods is provided below (Cho et al. 2011, Pike and Miles 2013). • Grinding methods (Figure 3) (e.g., carbide grinding or diamond grinding) use revolutions of an abrasive surface, such as disks, spindles, or drums, to remove the pavement marking. • High-pressure water blasting (Figure 4) uses a water jet at high pressure (typically at least 10,000 pounds per square inch) to eradicate pavement markings. Source: ATSSA 2014 Figure 2. Temporary raised pavement markers (TRPMs) (a) tabs and (b) buttons.

8 Temporary Pavement Markings Placement and Removal Practices in Work Zones Materials Application Durability Pros Cons Paint Machine 1 year or less Low cost ($0.10– 0.15/ft); wet-reflective elements can be added Low durability under heavy traffic; low quality under wet weather. Thermoplastic Machine 3 to 5 years High durability High cost ($0.70– 3.00/ft); medium wet weather recovery; difficult to remove. Epoxy Machine 3 to 5 years High durability High cost ($0.70– 3.00/ft), medium wet weather recovery; and contrast hard to see on new concrete. TRPM: Tabs Installed by hand Less than 1 year; less than 1 month under heavy traffic Low cost; high visibility under wet weather; flexible installation Possible littering; vandalism; best in warm weather application. TRPM: Buttons Installed by hand or by machine 1 year Low cost; audible and tactile clue to driver Not conducive for snowplows; small target value. Source: ATSSA 2014. Table 1. Overview of temporary pavement markings from ATSSA Guidance for the Use of Temporary Pavement Marking in Work Zones. Item Description Units [linear foot (LF)] Average Price Temporary 4-In. White Line LF $0.19 18 Temporary 4-In. White Line, Temporary Pavement Marking Tape LF $1.38 4 Temporary 4-In. White Line, Paint LF $0.10 79 Temporary 4-In. Yellow Line LF $0.19 17 Temporary 4-In. Yellow Line, Temporary Pavement Marking Tape LF $2.49 2 Temporary 4-In. Yellow Line, Paint LF $0.11 78 Temporary 6-In. White Line LF $0.50 2 Temporary 6-In. White Line, Temporary Pavement Marking Tape LF $1.08 7 Temporary 6-In. White Line, Paint LF $0.12 27 Temporary 6-In. Yellow Line LF $0.50 1 Temporary 6-In. Yellow Line, Temporary Pavement Marking Tape LF $0.86 5 Temporary 6-In. Yellow Line, Paint LF $0.11 19 Source: Vermont Agency of Transportation 2020. Contract Occurrences Table 2. Average unit prices (January 2015 to January 2020) for temporary pavement markings from Vermont Agency of Transportation.

Introduction 9   • Sandblasting (Figure 5) shoots very ne materials at a fast rate to remove the pavement markings. • Hydroblasting is similar to water blasting but uses sand in addition to high-pressure water. According to NCHRP Report 759: Eective Removal of Pavement Markings, the term hydro- blasting is frequently used for high-pressure water blasting (Pike and Miles 2013). For purposes of this synthesis, water blasting encompasses both high-pressure water blasting and hydroblasting. • Shot blasting (Figure 6) is similar to sandblasting but uses small steel balls instead of ne materials. • Dry ice blasting (Figure 7) propels the solid form of carbon dioxide at the pavement at high velocity. • Soda blasting (Figure 8) is similar to other blasting techniques but uses sodium bicarbonate (Truini 2013). Source: Cho et al. 2011 Figure 3. Example of grinding on asphalt pavement. Source: Ellis et al. 1999 Figure 4. Example of water blasting.

10 Temporary Pavement Markings Placement and Removal Practices in Work Zones Source: KC Power Clean 2015 Figure 5. Example of sandblasting. ©AAA Striping and Seal Coating Service 2017 Figure 6. Example of shot blasting. Source: Cho et al. 2011 Figure 7. Example of dry ice blasting.

Introduction 11   • Chemical (Figure 9) involves the application of paint strippers in liquid or gel form followed by rinsing with a simple water jet. • Burning includes various methods that typically mix propane in a combustion chamber with hot compressed air or excess oxygen. • Laser was evaluated for removal of paint pavement markings in a NCHRP IDEA study (Pew and orne 2000). • Masking includes several methods used to cover existing markings, such as milling, black tape, and slurry seal. Milling (Figure 10) involves removing a partial thickness of the pave- ment surface, including existing pavement markings. Black tape (Figure 11) may be placed over existing markings in lieu of removing them. A slurry seal (Figure 12) is a pavement preservation treatment that involves the placement of a mixture of water, asphalt emulsion, aggregate, and additives on an existing surface of asphalt pavement. ©Ontario Blasting Specialties 2016 Figure 8. Example of soda blasting. Source: Cho et al. 2011 Figure 9. Example of chemical removal.

12 Temporary Pavement Markings Placement and Removal Practices in Work Zones Source: Stanley Paving n.d. Figure 10. Example of milling. ©Insite Solutions, LLC 2020 Figure 11. Example of black tape used to cover existing pavement markings. Source: Pavement Interactive n.d. Figure 12. Example of slurry seal.

Introduction 13   Additional information regarding the various methods from a previous study, including pros and cons, is shown in Table 3. As shown in the table, grinding is fast and inexpensive but leads to pavement scarring. Water blasting is also fast and causes less scarring, but it is more expensive with less availability than grinding. Cost data for pavement-marking removal methods from a research study by Cho et al. (2011) are shown in Table 4. e data show that grinding is relatively inexpensive, especially compared to water blasting. In addition, the cost of shot blasting varies widely based on pave- ment and marking type. Removal Method Advantages Disadvantages Grinding • Fast and economical • Depending on the system configuration (effective vacuum system installed to remove dust), dust created by removal can be contained • High availability • Effective at reducing the thickness of thick marking materials such as thermoplastic or multiple layers of paint prior to restriping • Damage to pavement surface • Scarring with full marking removal • Minimizing damage to roadway may leave marking material behind • Orbital flailing may result in less noticeable scarring than drum flailing due to tapered edges • Non-vacuum systems can create dust clouds and be hazardous • Tape removal can be messy High-Pressure Water • Byproduct does not create dust and is contained within the equipment • Little to no scarring on good PCC • With the exception of drying time, the pavement surface is prepped for pavement marking reinstallation • Relatively fast for a blasting method especially for thin marking materials • Large vehicle mobile systems available with additional utility carts for smaller nearby areas • Limited to above-freezing conditions • May polish surface aggregate and/or clean the surrounding pavement, creating a color contrast • May remove some surface asphalt and fines that could lead to water penetration • Potential for damage to pavement joints • Proper equipment operation critical to achieve good results • Currently not widely available, higher costs Sandblasting • Minimal pavement degradation • Little to no scarring • Hand-operated precision • Effective on thin markings • Creates considerable byproduct • Creates considerable dust • No current large vehicle mobile system, therefore slower than mobile methods • Health hazards depending on blast media • Less effective on thick markings Shot Blasting • Minimal pavement degradation • Little to no scarring • Minimal byproduct • Byproduct does not create dust and is contained within the equipment • Shot recovery can be problematic especially on uneven surfaces • Cannot be used in wet conditions • Can be slow especially for thicker markings • Can cause pavement damage on non-smooth surfaces • Limited availability of equipment Other Media Blasting (Dry Ice, Soda, etc.) • Minimal pavement degradation • Little to no scarring • Minimal environmental concerns with respect to debris generated • Marking can be completely removed • Hand-operated precision • Can create a moderate amount of byproduct • Can create considerable dust • Can be slow especially for thick markings • Only useful on some markings, typically paint only • Dry ice is a difficult medium to handle and store • Very noisy • No current large vehicle mobile system Table 3. Advantages and disadvantages of pavement-marking removal methods. (continued on next page)

14 Temporary Pavement Markings Placement and Removal Practices in Work Zones Removal Type Marking MarkingSize Cost per Linear Foot Chemicals Concrete Water-Based 12 mils $0.33 Concrete Solvent-Based 20 mils $0.41 Asphalt Water-Based 20 mils $0.83 Asphalt Solvent-Based 12 mils $0.48 Water Blasting Concrete Water-Based 20 mils $2.14 Concrete Solvent-Based 12 mils $4.39 Asphalt Water-Based 12 mils $0.58 Asphalt Solvent-Based 20 mils $5.86 Asphalt Tape 4 in. $0.09 Dry Ice Blasting Concrete Water-Based 12 mils $3.37 Concrete Solvent-Based 20 mils $26.00 Concrete Tape 4 in. $0.06 Asphalt Water-Based 20 mils $0.22 Asphalt Solvent-Based 12 mils $0.73 Shot Blasting Concrete Water-Based 20 mils $0.12 Concrete Solvent-Based 12 mils $15.95 Asphalt Water-Based 12 mils $3.47 Asphalt Solvent-Based 20 mils $0.55 Asphalt Tape 4 in. $0.02 Scarifier Concrete Water-Based 12 mils $0.19 Grinding Concrete Solvent-Based 20 mils $0.15 Heat Torch Concrete Tape 4 in. $0.11 Grinding Asphalt Water-Based 12 mils $0.58 PCC Asphalt Solvent-Based 20 mils $0.80 Scarifier Asphalt Tape 4 in. $3.25 NOTE: PCC = Portland Cement Concrete. Source: Cho et al. 2011. Table 4. Cost data for pavement-marking removal methods. Table 3. (Continued). Removal Method Advantages Disadvantages Chemical • Byproduct does not create dust • Can get complete removal without scarring • Potential to damage pavement surface if incorrect removing agents are used • Requires at least one additional pass to remove residue • Slow, need to wait for chemical to react then proceed with removal • Some chemicals may pose an environmental risk • No current large vehicle mobile system • Only useful on some markings, typically paint Masking • No damage to road surface • Existing markings can be temporarily covered with tape that matches the road surface color and texture, and later reused when the tape is removed • Removed areas can be masked to help blend in scarring or surface color changes • Can be used in lane-shift areas to reduce driver confusion due to ghost markings or scarring • Can be expensive • Material may wear away, exposing the markings being covered • Difficult to match color and texture with tape • Tape is for temporary purposes only • Cannot use marking materials other than tape to cover a marking NOTE: PCC = Portland Cement Concrete. Source: Pike, A. M., and J. D. Miles. NCHRP Report 759: Effective Removal of Pavement Markings, Appendix E, Transportation Research Board of the National Academies, Washington, D.C., 2013. Reproduced with permission of the Transportation Research Board.

Introduction 15   Synthesis Methodology e synthesis approach included a literature review, survey, and case examples. e existing literature from many dierent sources—including guides and research reports as well as DOT policies, standards, and specications—was reviewed and synthesized. An online survey was distributed to the DOTs for all 50 states and the District of Columbia. Responses were received from all 51 agencies, leading to a 100% response rate. Follow-up interviews were conducted with representatives from seven DOTs to develop case examples of agencies’ experiences with temporary pavement markings in work zones and pavement marking removal. Synthesis Organization e following chapters of this synthesis are organized as follows: • Chapter 2 describes the comprehensive literature review of research, guidance, policies, standards, and specications. • Chapter 3 provides information on DOT practices based on the survey results. • Chapter 4 contains case examples for seven DOTs. • Chapter 5 presents the conclusions of the synthesis and recommendations for future research. • Appendix A, Survey Questionnaire; Appendix B, List of Responding Agencies; Appendix C, Individual Survey Responses; Appendix D, Summary of DOT Guidance for Temporary Pavement Markings and Pavement Marking Removal; Appendix E, Summary of DOT Speci- cations for Temporary Pavement Markings and Pavement Marking Removal; Appendix F, Summary of DOT Design Standards for Temporary Pavement Markings and Pavement Marking Removal; Appendix G, Temporary Pavement Markings and Marking Removal Methods by Climate Region; and Appendix H, Frequency of Use of Pavement-Marking Removal Methods Based on Frequency of Use of Paint, Tabs, and Temporary Tape provide supplemental information for the synthesis.