Implementation of Subsurface Utility Engineering for Highway Design and Construction (2022)

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7   This chapter serves as the background for the survey results presented in Chapter 3 and case examples described in Chapter 4. The literature review provides an overview of recent research and current practices regarding SUE implementation at state DOTs. The chapter begins with a discussion of the development and history of SUE as a practice, continues with the standards defining and supporting SUE by ASCE and other agencies, and concludes with the documented impacts and research related to implementing SUE. The literature demonstrated the progression and evolution of SUE since its beginnings in the 1980s when lack of certainty about underground utilities and traditional project-development approaches in dealing with utilities (i.e., highway design without regard to utilities) led to the need for new practices. These challenges led to early underground-utility-investigation practices, such as vacuum excavation and geophysics, which started without a standard and were geared toward underground facilities only (FHWA 2018b). The literature review discusses some of the SUE technologies and their advancement. Over time, SUE evolved into a standardized field of engineering, incorporated more advanced practices and technologies, involved more advanced utility infrastructure, and combined aboveground utilities with subsurface utilities. The review also highlights the standardization of SUE practice through the efforts of the ASCE and other agencies. At the time of this writing, this report, ASCE/CI 38-02, was the current National Consensus Standard to the process known as SUE. While the standard was developed from ASCE’s Construction Institute (CI), it is commonly referred to as ASCE 38-02 and is refer- enced as such within this report. Knowledge and standardized practices are still evolving, and there is currently an impending revision to ASCE 38-02. The revision of ASCE 38-02 will be referenced as ASCE 38, followed by the two-digit year of its publication. Along with the revision, ASCE has developed a standard guideline for recording and exchanging utility-infrastructure data (to be referenced as ASCE 75), which is awaiting publication as well. It is worth noting that the standardized SUE practice is promoted and supported not only by ASCE but also by FHWA, the National SUE Association, and others. The final area of review summarizes the documented impacts and past research regarding the implementation of SUE. Thus far, there have been a number of studies to show the potential value in implementing SUE. The literature-review results provided insight for the survey and case examples and helped to highlight the potential research needs discussed in Chapter 5. C H A P T E R   2 Literature Review

8 Implementation of Subsurface Utility Engineering for Highway Design and Construction 2.1 Historical Perspective on Subsurface Utility Engineering and Underground Utilities 2.1.1 Burden of Underground Utilities Understanding the location of underground utilities became critical during the construction and excavation operations involved in the building boom of the 1950s, 1960s, and 1970s (Thorne et al. 1993). During this time, there were several factors that led to the need for subsurface-utility investigation, including an increase in the number of underground facilities. The number of underground-utility installations increased due to technological advances in wire coatings and a growing emphasis on beautifying landscapes (Sturgill et al. 2018). With this increase in under- ground utilities, there was an increase in dig-in strikes, resulting in loss of services, injuries, delays, and even deaths. This promoted the initial establishment and growth of utility-location call centers (Sturgill et al. 2018). The earliest location call centers, the precursor to One Call, were formed from a clearinghouse beginning in 1964 (Thorne et al. 1993). Although the intent of these centers was for damage prevention during construction, their need and the abundance of under- ground infrastructure pointed to a larger problem requiring coordination between aboveground- and subsurface-infrastructure systems. Historically, underground-utility information has been incomplete or inaccurate. Recognizing this, engineers that work on projects with underground utilities have used exculpatory language in their contracts to protect themselves, including statements such as: “Utilities depicted on these plans are from utility owner’s records. The actual locations of utilities may be different. Utili- ties may exist that are not shown on these plans. It is the responsibility of the contractor at time of construction to identify, verify, and safely expose the utilities on this project” (Lew 1999). This approach shifted the burden of tracking these utilities to the contractor. While the One Call system has been established to reduce the risk of utility damages, utility owners generally do not maintain accurate as-built drawings (Meis et al. 2020). Thus, contractors have historically had minimal knowledge of utility locations. Because contractors assumed this risk, they would increase bid prices to account for this contingency, file change orders, and make claims when necessary (Lew 1999; FHWA 2018a). The project owner was then obligated to pay for these change orders and claims due to utilities being treated as a “differing or unknown site condition” in standard contract documents. 2.1.2 Brief History of SUE By the 1970s and owing to the amount and uncertainty of underground utilities, it was becoming apparent that the approach of designing highway projects without regard to utilities was not effective (FHWA 2017). Help came from the utility industries themselves and, specifically, the gas industry. Henry “Garon” Stutzman was a relocation engineer for the Washington Gas Light Company. By the 1970s, he had come to believe that relocations were largely a waste of taxpayer and ratepayer dollars. He was aware of the approach of using vacuum and air excavation to replace corrosion-protection anodes for gas lines and saw that as an opportunity to locate sub- surface utilities with minimal disturbance (Anspach 1997). In 1982, Stutzman, with financial backing from a Washington-area contractor, W. R. Owens, founded the first subsurface-utility- locating company called So-Deep. This company was focused on gathering data on the exact location of utilities prior to design and eventually became the first SUE company. In looking for additional methods for application, Stutzman and a colleague were introduced to new utility- locating techniques through James H. Anspach, a Pennsylvania State University geophysicist specializing in civil applications for geophysics (Anspach 1997). The introduction of these advanced techniques made it vital to differentiate between “des- ignating” and “locating.” Designating became known as the process of determining a utility’s

Literature Review 9   existence and approximate location through interpretation of an energy field of some kind, whereas locating became known as the process of actually exposing a utility. To date, these practices remain much the same (Anspach 1997). In the early 1980s, it became apparent that transportation projects were still experiencing unnecessary relocations, construction delays, and encounters with unknown utilities, and the use of vacuum excavation and geophysics began to be implemented by some DOTs (FHWA 2017). For example, in 1983, the Virginia DOT (VDOT) piloted utility-locating services and hired So-Deep to confirm “certified” locations from the utility company. With vast discrepancies identi- fied and caught before construction, VDOT realized substantial savings. By 1985, VDOT contracted with So-Deep to perform subsurface investigations statewide, and by 1986 they added utility- relocation-design-and-coordination services to their contracts. This meant that SUE was becoming a formalized field of engineering and now had components of designating, locating, and utility- relocation design (Anspach 1997). Over time, the practice of SUE services became more rigorous. States like Virginia determined that the services of an experienced land surveyor were necessary, whereas other states neces- sitated that this work must be sealed by a registered professional engineer, and still others required geologists to perform the work. In 1989, the first court case ruled that SUE services were professional services rather than contractor services. This was partially determined because statutes governing the practice of geology, land surveying, and engineering in Virginia were involved in the collection and interpretation of data supplied by subsurface-utility engineers (Anspach 1997). In the 1990s, technology and geophysics were advancing. For example, there was the first appli- cation of ground-penetrating radar (GPR) for subsurface-utility designating. These advances led to the promotion of SUE by So-Deep and FHWA, and So-Deep demonstrated various desig- nating and locating techniques for the DOE. During discussions regarding the demonstration project and drawing parallels of utility issues with nuclear-safety concepts, the four “utility quality levels” were born. This concept caught the attention of several other state and federal agencies (Anspach 1997). By the late 1990s, broadscale support and use of SUE led the ASCE to begin establishing a national standard regarding the responsibilities of engineers, project owners, and contractors for the collection and depiction of utility data on design and construction documents (Anspach 1997). This standard eventually became known as ASCE 38-02, the “Standard Guideline for the Collec- tion and Depiction of Existing Subsurface Utility Data.” 2.2 Evolution of Subsurface Utility Engineering Tools and Technologies As mentioned, one area of tools and technologies seeing the most advancement for SUE appli- cations has been geophysical tools. These techniques typically align with judging SUE QLB loca- tion information. FHWA notes that the proper selection of subsurface geophysical methods for QLB cannot be overlooked. They call out electromagnetic methods (e.g., pipe and cable locators, GPR, metal detectors, and so forth), magnetic methods, and elastic-wave methods (e.g., reso- nant sonic, active sonic, and passive sonic). These are further discussed within ASCE 38-02, but all have their advantages and drawbacks in locating utilities (FHWA 2018b). The appendix of the ASCE 38-02 standard also presents a summary of methods and SUE approaches. Previous studies provided an excellent basis and background regarding many of these tech- nologies, as discussed in the following. Jeong and Abraham prepared a paper, titled A Decision

10 Implementation of Subsurface Utility Engineering for Highway Design and Construction Tool for the Selection of Imaging Technologies to Detect Underground Infrastructure, where they present various SUE technologies along with conditions of their application and a decision support tool (2004). Table 2.1 presents the various electromagnetic methods prepared by Jeong and Abraham, discussing the application criteria of each (2004). They go on to note that the selection of these methods is dependent upon criteria, including utility type, the material of the utility, assembly and joint types, tracing materials used, access points, ground surface and soil types, state of the contents within the utility conduit, depth, and size of the utility (Jeong and Abraham 2004). Application Features of Electromagnetic Methods Electromagnetic Methods Application Features Crew and Effectiveness Pipe and cable locators Conductive mode (Low frequency) Only metallic objects can be detected Direct hookup to the utility line Frequency range: 220–640 Hz Good for tracing utilities Crew size: 1–2 people Effective depth: <15 feet (4.6 m) Pipe and cable locators Conductive mode (High frequency) Only metallic objects can be detected Direct hookup to the utility line High chance of coupling of the electromagnetic wave to adjacent utilities Frequency range: 8–480 kHz Good for tracing utilities Not good for low-conductive joints Crew size: 1–2 people Effective depth: <15 feet (4.6 m) Pipe and cable locators Inductive mode Only metallic objects can be detected Frequency range: 8–480 kHz Surface-utility appurtenance is required Indirect-energy generation from the surface Crew size: 1–2 people Effective depth: <6 feet (1.8 m) Pipe and cable locators Passive mode No transmitter is required Frequency: 50 Hz Good for searching metallic or live electric lines Crew size: 1–2 people Effective depth: <4.5 feet (1.4 m) Pipe and cable locators Sonde insertion method Specially designed transmitter (sonde/probe) Direct insertion of sonde to the underground utility Good for nonmetallic drain, sewer pipe, or ducts Surface connection is necessary, such as a manhole Crew size: 2 people Pipe and cable locators Tracing wire or metallic marking tape method Tracing wire/metallic marking tape must be installed in the construction stage of the utility Pipe and cable locator with conductive mode is generally utilized Crew size: 1–2 people Effective depth: <15 feet (4.6 m) Imaging technologies Terrain conductivity Typically metallic objects can be detected Can detect other features of different conductivity from the surrounding soil Good for searching utilities (insulated metallic utilities, underground storage tanks, wells, and vault covers) Useful in nonutility congested area Crew size: 1 person Effective depth: <15 feet (4.6 m) E-line locators Requires E-line locators as well as pipe and cable locator Digging a hole/creating an access point to the utility is necessary Installing an electro-line through the access point Pipe and cable locator with conductive mode is generally utilized Currently used for plastic gas pipe Exact location for pipe is required Crew size: 2 people Metal detectors Metallic objects can be detected Applicable for shallow manhole lids, valve-box covers, and so on Good for searching utilities Crew size: 1 person Effective depth: <2 feet (0.6 m) Electronic marker systems (EMS) Electronic markers must be installed in the construction stage Different frequency of electronic markers required for different types of utilities Typical spacing of markers: 60 feet (6.1 m) Usually used for marking of special buried features such as valves, splices, etc. Crew size: 1 person Ground-penetrating radar (GPR) Both metallic and nonmetallic utilities may be imaged Frequency range:1MHz–1GHz Good for searching/tracing utilities Poor ability on highly conductive soils such as clay, heavily saturated soil, etc. Crew size: 1–2 people Geophysicist or highly trained engineer’s analysis required Effective depth: <6 feet (1.8 m) Note: Effective depth was not provided for all methods within the materials used to recreate this table. Table 2.1. Electromagnetic SUE technology applications (recreated from Jeong and Abraham 2004).

Literature Review 11   Method Application Major Advantages Major Limitations Ground-penetrating radar • Utility detection and tracing • Ability to detect both metallic and nonmetallic utilities • Can be used for initial searches of larger areas • Relatively short detection range • Reliability largely depends on utility dimensions, utility materials, buried depth, and soil conditions • Cannot detect utility type • Data is difficult to interpret Pipe and cable locations • Utility detection and tracing • Especially suitable for tracing metallic utilities or nonmetallic utilities when tracing wires are accessible • Can be used in both a passive mode and an active mode (see following section) • A large variety of instruments available • Results affected by factors such as utility diameter, ground conductivity, existence of other conductors • Extremely prone to environmental interferences when used in passive mode • Accurate detection and tracing require access to utilities • Depth estimation is not reliable Ground-penetrating radar and/or electromagnetic induction arrays • Utility detection and tracing • More reliable and accurate results than traditional GPR and pipe and cable locators • Capable of 3-D utility mapping • Less portable than traditional GPR equipment and pipe and cable locators • Requires sophisticated software for data processing Terrain conductivity • Utility detection • Detection distance is relatively high • Suitable for search of isolated utilities • Can detect nonmetallic utilities • Prone to interferences by nearby electromagnetic noises • Not suitable for tracing utilities • Incapable of depth estimation • Reliability largely affected by soil type Beyond electromagnetic methods, other studies present a larger range of methods available for utility investigation, including mechanical waves, gravity, and temperature, among other mea- surement aspects. A valuable summary discussing these methods is provided in reports by Kraus et al., Utility Investigation Best Practices and Effects on TxDOT Highway Improvement Projects (2013), and by Sinha et al., Subsurface Utility Engineering Manual (2007). Kraus et al. also pro- vided concise tables illustrating the advantages and limitations of an assortment of investigation technologies. These are presented in Tables 2.2 and 2.3. While the studies previously mentioned provide a synopsis-level understanding of these tech- nologies used for geophysical-utility investigations, each could be investigated in-depth and in detail. For example, in a brochure provided by Radiodetection, titled The Theory of Buried Cable and Pipe Location, details are presented regarding the technologies and approaches of using cable and pipe locators (2017). While these types of approaches may have been first used in the early 1900s and are founded on nineteenth-century technology, the science behind them is quite com- plex. In fact, in an Underground Construction magazine article, Anspach noted that pipe and cable locators are some of the most sophisticated geophysical tools available in recent years. The issue with the use of these devices has been that few technicians know the full range of the device’s capabilities and their setup (2018). The details presented by Radiodetection’s brochure illustrated these complexities, the need for properly trained users, and an understanding of the utilities being investigated and their in situ conditions to achieve relevant results (2017). As pipe and cable locators have advanced in antenna and frequency availability, so too has GPR equipment. One example of GPR advancement was presented by Young and Kennedy in their report Utility-Locating Technology Development Using Multisensor Platforms (2015). This report was Table 2.2. Frequently used SUE approaches (recreated from Kraus et al. 2013).

12 Implementation of Subsurface Utility Engineering for Highway Design and Construction prepared for a project conducted under the Second Strategic Highway Research Program R01B topic of Utility Locating Technologies. The project focused on two advanced utility-identification technologies: multi-channel ground-penetrating radar (MCGPR) and time domain electro- magnetic induction (TDEMI). Similar to other GPR use, MCGPR signals are found to be limited in clay, otherwise conductive soils, or those with high water tables. TDEMI is effective in highly conductive soils for identifying metal utilities or utilities with a metal tracer wire. A significant finding of the research effort is that investigation methods can be most successful when combined with consideration of the utility, terrain, and other conditions and attributes involved in the investigation (Young and Kennedy 2015). Further noted was the importance of postprocessing data and software applications. Software applications and combined technologies have been significant contributors to the advancements in utility-investigation equipment. As noted in a Trenchless Technology article titled “High Resolution Multichannel GPR for Efficient Utility Mapping,” MCGPR technol- ogy, while more expensive to capture than more traditional GPR, allows for coverage of large areas and presents the ability for 3-D representation of utilities through certain software platforms (2020). Traditional GPR and other technology combinations are seeing additional advance- ments. Examples include recently developed 3-D GPR equipment capable of collecting data at high speeds (up to 80 miles per hour) and combination technologies such as the SPAR 300. The SPAR is a surveying and mapping technology using magnetic sensors and theoretical models of expected pipe magnetic fields to map the potential location of the utility based on the SPAR’s known location from the global navigation satellite system (GNSS) coordinates. Additional com- binations are using GPR and light detection and ranging (LiDAR) to capture aboveground and belowground features and stitching them together into a single 3-D model (Zeiss 2018). Beyond the SUE QLB technologies, it is important to discuss the approaches for SUE QLA. Sinha et al. discuss these approaches and note their selection is relative to field conditions and the utility being investigated (2007). It is important to note that QLB information is critical to the investigations using QLA. Each test pit or hole investigated for QLA information incurs significant costs compared to the lower-quality-level methods. QLA is typically a small exposure or Method Application Major Advantages Major Limitations Resistivity measurements and capacitive resistivity method • Utility detection • Suitable for general utility searching • Data collection and interpretation are difficult compared to other methods and require experienced personnel Magnetic methods • Utility detection • Suitable for searching over a large area • Suitable for utilities marked with magnets • Shallow detection range • Not capable of depth estimation • Prone to interference from nearby magnetic sources Infrared thermography • Utility detection • NA • Shallow detection range • Requires very sensitive equipment • Not capable of depth estimation Acoustic location • Utility tracing • NA • Prone to interference from background noise • Requires access to or prior knowledge of utilities • Not capable of depth estimation Microgravitational techniques • Detection of very large underground objects • NA • Requires very precise measurements and experienced personnel Table 2.3. Infrequently used SUE approaches (recreated from Kraus et al. 2013).

Literature Review 13   hole to find and survey the exact location and dimensions of a facility at a specific point or location. QLB is also desirable to help the identification of what was actually found in the test hole. If a test pit misses the target due to poor QLB information, additional work becomes necessary. Beyond typical excavation operations to achieve QLA, vacuum-excavation methods may be employed. As Sinha et al. explain, the choice between air-vacuum excavation and hydro-vacuum (water) excavation is dependent on soil type, water tables, and other attributes (2007). Water table and soil or groundwater contamination may be additional concerns to consider by those providing the SUE investigation. 2.3 Standardization and Promotion of Subsurface Utility Engineering The ASCE developed the National Consensus Standard (NCS) for SUE, titled ASCE 38-02, “Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data.” As an NCS, developed through ASCE and American National Standards Institute (ANSI) standard adop- tion procedures, the justice system holds high regard for the standard. ASCE 38-02, therefore, assists in both defining the professional standard of care and in the adjudication of blame within SUE practices (FHWA 2018b). In support of this standardization and the promotion of SUE as a professional practice with a standard of care, the SUE Association was formed in 2018 to support and protect the interests of the SUE provider community (SUE Association 2020). This group has further advocated the use of SUE and SUE service scoping of state DOTs. The execution of these actions varies sig- nificantly by state DOTs, though many hire consultants to perform SUE work. As of 2004, SUE contracts were awarded as cost-plus-fee (42% of all contracts), unit-price (32%), daily-rate (14%), and lump-sum (12%) contracts (Jeong et al. 2004). The appropriate selection of these contract types involves a balancing of advantages and tradeoffs between the state DOTs and consultant SUE providers across the scope of the services required. The FHWA Program Review notes that Indefinite Delivery Indefinite Quantity (IDIQ) approaches can be a useful alternative by providing a balance of cost and risk for SUE services (FHWA 2018a). The growth in the number of SUE providers and cross-industry support not only led to the development of the SUE Association but also led to the development of ASCE’s Utility Engineering and Surveying Institute (UESI). UESI represents professionals in utility and pipeline engineering, surveying, and geomatics communities and offers opportunities for networking and shaping the future of the industry through technical activities, continuing education, conferences, and the devel- opment of internationally recognized standards (ASCE 2020). UESI defined utility engineering as: A branch of Civil Engineering that focuses on the planning, position, design, construction, operation, maintenance, and asset management of any and all utility systems, as well as the interaction between utility infrastructure and other civil infrastructure (ASCE 2020). UESI is leading the charge in the standardization of practice around what is currently referred to as SUE and utility engineering. The UESI activities are highlighted in the evolution of the ASCE 38-02 standard as they have taken over the ownership of that standard from the Construc- tion Institute. 2.3.1 ASCE 38-02 ASCE’s 38-02’s “Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data” was published and distributed in 2003. ASCE 38-02 elevated utility investiga- tions to a professional effort and created the industry standard for achieving the level of care to assess and appropriately address and mitigate utility risk for project development. In addition to describing relative costs and benefits, the standard provides guidelines for collecting and

14 Implementation of Subsurface Utility Engineering for Highway Design and Construction designating the quality of utility information depicted on plans, as well as using professional judg- ment in a standardized manner (FHWA 2018b). The ASCE standard clarifies that SUE is a process, not a technology. ASCE 38-02 defines SUE as a branch of engineering practice that involves managing certain risks associated with: • Utility mapping at appropriate quality levels; • Utility coordination; • Utility-relocation design and coordination; • Utility-condition assessment; • Communication of utility data to concerned parties; • Utility-relocation cost estimates; • Implementation of utility-accommodation policies; and • Utility design (FHWA 2018b). These activities, combined with traditional records research, site surveys, and the utilization of new technologies, such as surface geophysical methods and nondestructive vacuum excavation, aim to provide “quality levels” of information (FHWA 2018b). ASCE 38-02 is undergoing a substantial revision that is expected to be published very soon. 2.3.2 ASCE As-Built Standard As of this publication, ASCE is also developing a Standard Guideline for Recording and Exchanging Utility Infrastructure Data (to be ASCE 75). This document is intended to comple- ment ASCE 38-02 and provide guidelines for documenting utility infrastructure when it is being installed or is exposed. Included is a standardization for spatial data and feature attri- butes that provide the data required to produce 3-D renderings of utility installations tied to real-world coordinates. Effectively, this latter ASCE standard is an “as-built” standard for docu- menting “newly installed” or exposed utility infrastructure, while ASCE 38-02 is a standard for documenting “existing” and already-buried utility infrastructure (Meis et al. 2020). The purpose of the as-built standard is to provide guidance to assist ROW and utility owners in establishing standards for as-built data collection. State DOTs have already used earlier draft versions of these guidelines for the development of as-built processes and data repositories. Yet, when complete and distributed, the standard guideline will present common definitions for communicating the positional accuracy of utility assets and define a minimum set of data attri- butes necessary to help understand a facility, along with type, function, ownership, materials, status, and the like. It is anticipated that the guideline will encourage the adoption of standard practices for documenting the location and attributes of underground- and aboveground-utility infrastructure, resulting in permanent records of the location determined by direct-measurement methods as facilities are installed. This would lead to future savings and understanding of utility facilities (ASCE n.d.). This new standard is much anticipated and has already been supported and adopted by some. For instance, the Open Geospatial Consortium (OGC) has already adopted the standard draft for their Model for Underground Data Definition and Integration (MUDDI) initiative (Lieberman and Roensdorf 2020). 2.4 Support for Using Subsurface Utility Engineering The use of SUE was supported by the FHWA even prior to the standard being developed by ASCE. FHWA’s Program Guide for Utility Relocation and Accommodation on Federal-Aid Highway Projects notes that FHWA has promoted the use of SUE within preliminary-engineering

Literature Review 15   project phases since 1991 and considers the cost of SUE services an eligible expense for federal aid. Further noted, the use of these professional services can eliminate: • Delays to projects caused by waiting for utility relocation work to be completed so highway construction can begin; • Delays to projects caused by redesign when construction cannot follow the original design due to unexpected utility conflicts; • Delays to contractors during highway construction caused by cutting, damaging, or discovering utility lines that were not known to be there; • Claims by contractors for delays resulting from unexpected encounters with utilities; and • Deaths, injuries, property damage, and releases of product into the environment caused by cutting utility lines that were not known to be there (FHWA 2003). The Program Guide provides monetary justification through savings reported by research (FHWA 2003). This supporting research, which highlights the return on investment in using SUE, is further detailed in a later section of this synthesis. The Program Guide notes that the Brooks Act applies to SUE services, and providers should be selected through quality-based approaches with care taken to ensure services and providers are qualified and are providing SUE according to the ASCE standard. The Program Guide goes on to note: States should no longer be relocating underground utilities unnecessarily or encountering them unexpect- edly on Federal-aid highway projects. The SUE technology is readily available to virtually eliminate these wasteful activities. Federal funds should not be used to participate in any unnecessary utility costs on projects where proven technologies, such as SUE, have not been used or have not been used properly (FHWA 2003). This long-term support for SUE has not resulted in its programmatic practice. A recent FHWA Program Review, National Utility Review: Utility Coordination Process, found: lacking accuracy in utility location information; incomplete utility relocation plans; lacking justification in relocation estimates; no relocation schedules; limited utility information communicated in bid packages; an inability to quantify cost and time increases to construction projects as a result of utilities; and limited oversight for relocation efforts (FHWA 2018a). The review further noted that these deficiencies are often tied to underground utilities where SUE was not adequately performed, and few DOTs are methodically using SUE, with only 23% having a programmatic risk-based approach (FHWA 2018a). The report goes on to state: These gaps are often tied to underground utilities where subsurface utility engineering or SUE is lacking. Most State DOTs do not adequately investigate underground utilities, especially vertical or depth (z coordi- nates), resulting in utility conflicts either being misidentified or not identified at all during the preconstruc- tion phase. This results in contractors unexpectedly encountering utilities during construction, a situation that often increases project cost or causes delays, or sometimes both (FHWA 2018a). The need is further highlighted by the FHWA Program Review, which noted: One reason why utility conflicts are unknown and thus increase project risk is that few DOTs methodi- cally use subsurface utility engineering (SUE) as a common practice. One of the program review survey questions collected during Phase 1 of this review asked State DOTs to briefly explain their process for locating utilities and whether they used SUE, utility company input, or as-built plans—those that depict the final location of the utilities. According to the survey, 27 State DOTs (53 percent) indicated that their primary method of utility investigation was as-built plans and the national subsurface utility locator service known as Call 811 or One Call (FHWA 2018a).

16 Implementation of Subsurface Utility Engineering for Highway Design and Construction There are two approaches currently used to address and reduce issues with utilities on projects: • SUE investigations and Utility Engineering (UE) design analytics and resolution develop- ment, which occur during project development; and • Damage Prevention (DP) practices utilizing One Call (Call 811) notifications, contract locating services, and related damage incident reporting, which occur at the time of excavation (Meis et al. 2020). SUE and utility engineering acquire depictions of utility infrastructure through methodical engineering and geophysical investigation performed in accordance with ASCE 38-02 and then integrating that data in project development to mitigate issues and risk during the planning and design of a project. In contrast, damage-prevention services are the focus of organizations such as the Common Ground Alliance (CGA) and contract locating industries to place marks and flag- ging (“locates”) on the ground during construction to identify utilities (Meis et al. 2020). SUE is fundamentally about reducing the risk associated with utilities by performing a thorough utility investigation and depicting that investigation in a risk-based format (Anspach and Scott 2019). The goal of these investigations is to reduce the uncertainty associated with historic records (or lack thereof), inaccurate visual indications, unclear geophysics, and inconsistent exposures (Anspach and Scott 2019). The realization of these uncertainties over the life of the project tends to drive up project costs and create delays as unexpected obstructions are identi- fied during the construction process. Projects that necessitate SUE are usually: • Urban-highway projects and utilities with a high potential of expected utility conflicts; • Underground-utility projects with congested utility networks and high potential of utility relocations; • Projects with limited, narrow, and congested ROW; and • Highway projects that have tight schedules (Sinha et al. 2007). Preliminary research on SUE showed the early utility-location and condition data could be used as a way to assure minimal delays and cost overruns (Kraus et al. 2013). Doing so provides more accurate and complete information about utility factors that will reduce conflicts within the project (Quiroga et al. 2012). The consequence of inaccurate or incomplete information about utility facilities can result in: • Disruptions when utility installations are encountered unexpectedly during construction, either because there was no previous information about those installations or because utilities were inaccurately depicted on the construction plans; • Damage to utility installations, which can disrupt utility service, damage the environment, and endanger the health and safety of construction workers and the public; • Delays that can extend the period of project development or delivery and increase total project costs, leaving the public’s transportation needs unmet; • Increased contractor bids to mitigate or compensate for the increased risks, costing tax- payers more; • Unnecessary cost and time increases because of change orders and other utility issues; • Jeopardized highway-worker and public safety due to unknown underground utility lines during construction; • Compromised public safety when utility-related project delays extend work zones, sometimes into the next construction season; • Strained relationships among state DOTs, contractors, and utility companies due to increased risks, lack of communication, and unknown and unexpected problems (FHWA 2018a; Meis et al. 2020).

Literature Review 17   Even with this support for using SUE, there have been lulls in its application in DOT pro- grams and projects as previously noted in the FHWA Program Review, National Utility Review: Utility Coordination Process (FHWA 2018a). NCHRP Synthesis 506: Effective Utility Coordination: Application of Research and Current Practices, provides insight into the use of SUE by DOTs. This synthesis found SUE to be ranked within the top-five practices considered effective for utility coordination by state DOTs but also identified SUE as an area where there is a need for improved understanding. Notably, an improved understanding and guidance on the use of SUE was the top-ranked research needed according to state DOTs (Sturgill et al. 2017). 2.5 Previous Extent of Subsurface Utility Engineering Use Along with the history, promotion, and support of SUE over time, there are previous studies indicating the extent of SUE use and its increase in use. Adapted from a So-Deep, Inc., presenta- tion delivered by Jim Anspach, Figure 2.1 illustrates where SUE had been implemented in 1992. The implementations represented were not exclusive to state DOT use. In some cases, the use within the state was not by the DOT but by other entities. The AASHTO CRUO conducted surveys in 2006 and 2008, presenting SUE use rates more than a decade later. These surveys found that 50% of the 2006 DOT respondents and 40% of the 2008 DOT respondents were implementing SUE. NCHRP Synthesis 506: Effective Utility Coordi- nation: Application of Research and Current Practices showed that the use rate increased to 74% by 2017 (Sturgill et al.). This baseline information will be compared to the survey results of this synthesis in Chapter 3 (83% of the survey respondents indicated that they implement SUE). Figure 2.1. States where SUE has been implemented circa 1992 (adapted from So-Deep Records).

18 Implementation of Subsurface Utility Engineering for Highway Design and Construction 2.6 Documented Impacts and Other Research Studies on Subsurface Utility Engineering SUE and utility-engineering practices have been the focus of organizations, including the ASCE, the TRB, and the FHWA. In the past two decades, a number of research studies have been performed to evaluate the benefits and costs of SUE implementation for these agencies. Several studies are presented in the following sections, along with their main findings. 2.6.1 Cost Savings Purdue University’s Department of Building Construction Management conducted a study titled “Cost Savings on Highway Projects Utilizing Subsurface Utility Engineering” for the FHWA (Lew 1999). The goal of this study was to determine if SUE provided reduced costs and fewer delays on highway projects. In a study of 71 SUE QLB and QLA projects across four states, Lew (1999) found that approximately $4.62 was saved for every $1 spent on SUE and that achieving a QLA or QLB was less than 0.5% of the total project cost. This was an additional construction savings of 1.9% over QLC and QLD projects. This meant that, for the $51 billion spent on highway construction during 1998, nearly $1 billion would be saved if SUE was systematically implemented on all QLB and QLA projects. This savings was based on 21 distinct categories that were quantified in terms of time and cost-saving and risk-management actions, which are presented later. Each of these categories was considered a benefit of performing SUE for the DOT. Time savings of 12–15% was also noted from the Virginia DOT projects. Furthermore, nonmeasurable qualitative savings was determined to be significant. Based on these findings, SUE was determined to be a practice that should be used systemically to reduce the cost of risks associated with existing subsurface utilities (Lew 1999). Benefits and cost savings offered by SUE: 1. Reduction in unforeseen utility conflicts and relocations 2. Reduction in project delays due to utility relocates 3. Reduction in claims and change orders 4. Reduction in delays due to utility cuts 5. Reduction in project contingency fees 6. Lower project bids 7. Reduction in costs caused by conflict redesign 8. Reduction in the cost of project design 9. Reduction in travel delays during construction to the motoring public 10. Improvement in contractor productivity and quality 11. Reduction in utility companies’ cost to repair damaged facilities 12. Minimization of utility customers’ loss of service 13. Minimization of damage to existing pavements 14. Minimization of traffic disruption, increasing DOT public credibility 15. Improvement in working relationships between DOT and utilities 16. Increased efficiency of surveying activities by elimination of duplicate surveys 17. Facilitation of electronic-mapping accuracy 18. Minimization of the chance of environmental damage 19. Inducement of savings in risk management and insurance 20. Introduction of the concept of a comprehensive SUE process 21. Reduction in ROW acquisition costs (Lew 1999) 2.6.2 SUE Manual and Cost-Benefit Analysis In 2007, the Pennsylvania Department of Transportation (PennDOT) commissioned Pennsyl- vania State University’s Transportation Institute to develop the “Subsurface Utility Engineering

Literature Review 19   Manual,” which would provide much-needed consistency in the implementation of SUE across districts in the state (Sinha et al. 2007). As part of this project, Sinha et al. (2007) developed three core resources: (1) a procedure for selecting the most beneficial means of SUE investigations based on the utility impact, (2) a decision matrix to evaluate the best quality level of SUE based on known (or unknown) conditions, and (3) a detailed cost-benefit analysis. The first and second core resources—the utility-impact assessment and the decision matrix— were intertwined tools that enabled engineers to determine the optimal SUE quality level com- mensurate with their expected site conditions. First, the utility-impact assessment provided a tool to evaluate the likelihood that utilities may impact the project, as well as the complexity of those utilities. The decision matrix then allowed engineers to better evaluate the risk and cost impact of selecting a quality level other than what would be optimal for that specific project (e.g., selecting QLA when only QLD was needed or vice versa) (Sinha et al. 2007). The third core resource, the detailed cost-benefit analysis, was based on 10 case studies per- formed with utility engineers, SUE consultants, designers, contractors, and PennDOT project managers and engineers. The total cost of these 10 cases exceeded $120 million, and the optimal quality level of each project was at least QLB, based on the application of the decision matrix to the cases. This cost-benefit analysis found that $22.21 was saved for every $1 invested in SUE and that achieving a QLA or QLB cost less than 0.6% of the total project cost. This offered a savings of over 15% of the traditional QLC and QLD. In general, this study noted that the cost benefit of using SUE increased as the utility complexity increased (Sinha et al. 2007). 2.6.3 Cost and Time Benefits for Using SUE (Louisiana State University Study) A study completed in 2021 by Louisiana State University titled “Cost and Time Benefits of Using Subsurface Utility Engineering in Louisiana” investigated the cost and time benefits of SUE for highway projects in Louisiana. Actual costs were used to determine these benefits, and therefore only projects that used SUE services after encountering utility conflicts during con- struction were evaluated (Mutoni et al. 2021). This reduced the documented savings of SUE used in preliminary-design stages to maximize benefits. However, within these parameters, this study found a realized cost savings of $2.73 for every $1 spent on SUE. This research also reviewed savings along both project type and size to determine where the most benefit from SUE was realized. Findings suggest the most savings was on larger, complex projects costing at least $3 million (Mutoni et al. 2021). 2.6.4 NCHRP Project 20-07/Task 389 In 2018, NCHRP Project 20-07/Task 389, “Implications of State Departments of Transpor- tation (DOTs) Participation in the One Call Process as an Underground Facility Operator,” reviewed One Call practices and legislation. The findings determined that One Call’s purpose is in damage prevention and is not an effective practice for avoidance in design, as it is not an alter- native to SUE. The report notes One Call is an important service but that it primarily serves as a liability-assignment mechanism and not a utility investigation (Sturgill et al. 2018). 2.6.5 Utility Location and Highway Design Synthesis In 2010, NCHRP Synthesis 405: Utility Location and Highway Design identified the core challenges between utility coordination and highway design (Anspach 2010). This synthesis determined that the severity of utility impacts are related to DOT procedures for identifying, locating, and resolving conflicts regarding utilities. Recognizing that DOTs have a wide array of procedures, this synthesis provided a succinct list of best practices to mitigate these utility and highway conflicts.

20 Implementation of Subsurface Utility Engineering for Highway Design and Construction 2.6.6 SUE Information Management for Airports Synthesis In 2012, TRB’s ACRP Synthesis 34: Subsurface Utility Engineering Information Management for Airports reinforced the concept that utility management and coordination are essential to appropriately address potential utility impacts on projects (Anspach and Murphy 2012). While a number of methods for identifying utility facilities were evaluated, one best practice determined from this study was the early involvement of SUE specialists that have knowledge of utility installations and proper investigative procedures. This early involvement allowed for improved identification and management of utility-conflict situations and reduced the associated risk. 2.6.7 Practices for Managing Utility Coordination in Transit Projects In 2015, TCRP Synthesis 118: Practices for Utility Coordination in Transit Projects reinforced the fact that incomplete utility-facility information was ubiquitous across projects. This incom- plete information may cause unexpected conflicts, but DOTs currently lack the necessary strategies to effectively resolve these knowledge voids. This synthesis further noted that the type of owner, the experience of the project team, and the timing of coordination on the project could significantly alter the amount and success of utility-coordination efforts. Furthermore, this synthesis determined that the application of utility-conflict matrices, 3-D technologies, and ASCE 38-02 was inconsistent across agencies. 2.6.8 Managing Longitudinal Installations on Controlled Access Highway ROW Synthesis In 2016, NCHRP Synthesis 462: Managing Longitudinal Utility Installations on Controlled Access Highway Right-of-Way examined how longitudinal utility installations were managed on controlled-access-highway ROWs (Kraus 2014). This synthesis showed that, although individual DOTs have their own practices and procedures for managing these projects (e.g., use of utility corridors, shared trench methods, and utility ROW accommodations), there was not a national standard of practice that could guide these procedures. Furthermore, this synthesis showed that the state of the practice had not yet achieved the implementation of procedures to acquire and manage geospatially accurate as-built utility data. 2.6.9 SUE and Alternative-Contracting Methods (NCHRP Project 20-07/Tasks 373 and 407) Two studies, which recently completed the investigation of utility coordination and practices in projects delivered using alternative-contracting methods (ACM), were NCHRP Project 20-07/ Task 373 and NCHRP Project 20-07/Task 407. In NCHRP Project 20-07/Task 373, “Utility Coordination Using Alternative Contracting Methods,” the authors point out five factors for consideration when implementing SUE in ACM projects: ACM contractor’s SUE involvement, the timing of SUE activities, required quality level, documentation, and updates (Gransberg et al. 2017). This report reviewed case practices and noted the importance of communicating SUE information and recommending how to imple- ment SUE investigations in ACM projects. It should be noted that the responsibility for SUE investigations can vary within an ACM project, and multiple considerations are needed. In NCHRP Project 20-07/Task 407, “Utility Coordination Efficiency, Safety, Cost, and Schedule Impacts Using Various Contracting Methods,” the authors make a high-level compar- ison for design-bid-build (DBB), design-build (DB, inclusive of public-private partnerships), and construction manager/general contractor (CM/GC). The authors note that DBB and CM/GC are

Literature Review 21   similar in their utility-coordination applications, while DB would necessitate a different approach (Taylor et al. 2021). Within the survey feedback of the report, a respondent notes that when utility coordination is provided by a consultant service in an ACM project, they are at times hesitant to procure SUE investigations (Taylor et al. 2021). In combination, these reports present that SUE within ACM projects, specifically DB, can be implemented in many configurations, which presents unique challenges. Ultimately, the applica- tion of SUE requires an understanding of when information is needed to benefit the project and what party is responsible for procuring the SUE investigation. 2.6.10 3-D Mapping-Feasibility Study (FHWA 2018) In 2018, the FHWA commissioned Quiroga et al. to evaluate the “Feasibility of Mapping and Marking Underground Utilities by State Transportation Departments.” This research conducted a detailed investigation of the feasibility and practical application of a DOT’s ability to capture and warehouse the location data of utilities within their ROW, with a specific focus on 3-D tech- niques. Quiroga et al. (2018) found that individual state DOTs can feasibly develop and maintain reliable inventories of utility facilities within state highway ROWs. However, state DOTs were not equipped to be a central repository of all authoritative information on the utility facilities. Although Quiroga et al. (2018) identified a number of benefits of 3-D modeling, the study was unable to quantify the economic benefits due to a lack of available data. This was primarily because the use of 3-D models had reached a point where the cost to develop a model was just considered the cost of doing business. Based on anecdotal evidence collected during this project, however, Quiroga et al. (2018) determined that the cost to develop 3-D utility inventories was primarily the cost to collect reliable, comprehensive data in the field. After the point of complete data collection, the actual work to develop the model itself was relatively minor. DOTs could further control costs by focusing on basic 3-D model functionality over the development of sophisticated renderings. 2.6.11 As-Built Study (NCHRP Project 20-07/Task 418) As part of the NCHRP Project 20-07/Task 418 study, titled “An Impact and Value Analysis of Requiring Geospatial Locations for Utility Installation As-Builts,” Meis et al. (2020) evalu- ated the current state of the practice of DOTs regarding the collection of geospatially referenced as-built utility-record data within the public ROWs. This research found that the collection of accurate utility as-builts was not performed as a standard practice across DOTs; rather, DOTs generally felt that the utility owner was responsible for obtaining and providing reliable as-built data on utility infrastructure. However, DOTs often received as-built documents from these utility owners that were not standardized. The as-built received may consist of an array of non- standardized records or drawings, which were often in a schematic, sometimes paper or image format, could not be imported or easily transcribed into useful digital form, and typically failed to represent or accurately depict utility facilities with proper reference to a published geodetic datum and established geographic coordinate system. Consequently, these documents did not assist in reducing project risk, project costs, and unplanned project delays for DOTs. If a DOT wanted to require professionally certified, geospatially accurate standardized-utility as-built data from utility owners, legislative action was most likely required. This study estimated that the return from developing as-built utility plans through survey practices would save DOT projects at least $20 for every $1 spent on surveying the utilities as installed (Meis et al. 2020). Meis et al. (2020) also provided some of the first research about the unique barriers that utility owners faced in providing as-builts for DOTs. Specifically, the Meis et al. (2020) case studies

22 Implementation of Subsurface Utility Engineering for Highway Design and Construction showed that the primary concerns from utility owners were in regard to the cost and resources necessary to collect, store, manage, and update geospatially accurate as-built data. According to a survey of utility companies, Meis et al. (2020) identified that, in addition to cost, the most common issues associated with acquiring as-builts from utility companies were perceived to be: • Lack of resources; • Lack of information or record; • Protection of intellectual property; • Security protection under the Homeland Security Act; and • Duplicating effort provided by the state One Call (Call 811) system. 2.7 Summary The literature review investigated numerous standards, policies, and studies that provide background for this synthesis on the implementation of SUE at state DOTs. This literature review presented SUE as a standardized process with measurable benefits. The information gathered influenced the development of the synthesis survey, the results of which are presented in the following chapter.