Encouraging Innovation in Locating and Characterizing Underground Utilities (2009)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

51C H A P T E R 6 Targeting ImprovementsIntroduction Thus far, the report has described the administrative and technical landscape within which utility locating and char- acterization efforts must operate. The focus of this chapter is on identifying how SHRP 2 could best encourage and accel- erate actions related to improving technological perfor- mance and developing systems, procedures, and funding or time allowances that permit the technology to make a signif- icant difference in the planning, design, and construction of highway renewal projects. Recommendations must necessarily take into consideration the expected time frame within which the investment’s effect will be realized. For example, some administrative and pro- cedural changes could be rapidly implemented, particularly when they are backed by administrative order or legislation. The adoption of some market-ready technologies could also be accelerated to within a few years’ time, whereas other longer- term technical developments and recordkeeping or mapping- technology changes could take decades for a full, nationwide implementation. This report takes into consideration the rela- tively short-term, targeted research mandate imposed by Con- gress on SHRP 2. Thus, this report’s recommendations target those areas for improvement that could potentially demon- strate a change in practice within 5 to 10 years. This does not mean, for instance, that the tagging and mapping of all under- ground utilities will have migrated to a new technology within 10 years, but rather that, for the foreseeable future, expecta- tions are optimistic that a working system could be operational within 10 years. It could serve as a model for extension to other areas and provide a commercially available system that DOTs and other agencies across the nation could adopt. Another stated SHRP 2 research program goal is to avoid duplication of similar efforts. Hence, research efforts in progress in North America and worldwide influence the selection of which research avenues to pursue.1ST REVUtility issues are not just an afterthought to transporta- tion project plans that need proper management. They are an increasingly important cost and schedule determinant. Despite present-day application difficulties and physical limitations, utility locating and characterization technologies may, in the mid to long term, improve in performance and in their ability to integrate into practice. Revisiting an analogy made in chapter 4, billions of dollars have been invested in medical imaging technologies to diag- nose problems and guide invasive surgery, and the results have been spectacular. Yet, the equivalent utility-imaging R&D efforts, which tackle challenges that are arguably even more dif- ficult than those faced by medical imaging, currently encounter less funding and a narrower body of research than those for medical imaging. This report’s recommendations are grouped in four cate- gories, although there is some overlap. These categories, which encompass technological and practical improvements, follow: utility locating through geophysical means, utility characteriza- tion, mapping and recordkeeping, and education and training. Implications from Case History Reviews As part of the current research-planning effort, case histories were collected and reviewed for utility-damage incidents and for utility-detection procedures that were adopted for various projects. The case histories were compiled into an electronic database, but only the case histories for utility detection and location processes and their outcomes are included in Appendix B. They come from a University of Toronto report (1), information compiled by SUE providers (2), a Penn State University report for PennDOT (3), and numerous individ- ual cases published in literature, such as conference papers, project reports, and vendor-provided technical materials. InISE

52many cases, information was combined from several sources to form a single case-history description. This section discusses the implications of the case histories on utility locating tech- nologies and procedures that were examined. A utility strike occurs nearly every minute somewhere in the U.S. (4, 5). Although most utility strikes result in minimal local damage, many others result in fatalities, injuries, signifi- cant collateral damage, or all of these. The cost of repairing the damaged utility is often overshadowed by costs associated with a) disruption of services, traffic, and normal life patterns; b) project delays; c) contractor claims; and d) litigation. The latter three are associated not only with utility strikes but also with near-miss events when utilities that are poorly marked or that were previously unknown are discovered during con- struction. The circumstances of the strike and the adequacy of the response could play as great a role as that of the utility type in determining the extent of the damage and loss incurred as a result of the accident. Observations also include the follow- ing: a) some contractors appear to place productivity ahead of regard for existing utilities, and such projects are often characterized by multiple utility strikes; b) fading or erased paint marks more than once appear to be a cause in the cases reviewed, suggesting a need for improved marking technolo- gies or procedures; and c) in some countries, utility compa- nies and municipalities are compensating users for indirect damage and loss. Subsurface utility engineering (SUE) mapping surveys con- sistently seem to positively affect the outcome when per- formed ahead of construction projects. It is not uncommon that agencies are driven to begin using SUE following one or more projects that went poorly because of multiple utility conflicts, serious utility-related accidents, or a combination thereof. From a review of the case studies compiled in Appen- dix B, it appears that conducting a quality level B mapping effort when design is about 30% completed has been effective, achieving a balance between design-detail availability and the redesign effort that, according to the updated utility location data, is needed. Current risk-management thought, such as is found in the policies of Virginia and Washington DOTs, is that SUE mapping surveys should be advanced to the 0% to 10% stage for even greater benefits. The benefit-to-cost ratio to project owners in the cases described in Appendix B ranged between 2 to 1 and 60 to 1, while the cost of the study ranged between 0.125% and 2% of the total project budget. These values are in line with a report published by Purdue Univer- sity (6), in which a study of 71 projects suggested an average benefit-to-cost ratio of 4.6 to 1. The additional costs associated with quality level B and quality level A SUE investigation were reported to be about 0.5% of the total construction costs. Other published studies indicate even higher rates of return, including the Virginia DOT study (7 to 1), Maryland DOT study (18 to 1), and the Society of American Value Engineersstudy (10 to 1). A recently published study by Penn State University for PENNDOT found a 22-to-1 cost ratio when it looked at 10 randomly selected PENNDOT projects (www. fhwa.dot.gov/programadmin/pus.cfm). It is important to note that in all cases only construction-cost and schedule-delay savings were considered. Costs associated with possible utility strikes and other qualitative measures— that is to say, the cost to road users—were not considered due to uncertainty associated with the parameters involved. The older and more developed the area where construction is scheduled to take place, the greater the benefit-to-cost poten- tial; also, the larger the scope of the project, the greater the benefit-to-cost ratio and the smaller the SUE investment as a percentage of the total budget. The cost of a SUE investigation increases with the quality level. Thus, all four investigation stages are usually employed systematically to maximize the benefit-to-cost ratio for this effort; for instance, eliminating utility designation from a SUE study could significantly reduce the effectiveness of the test-hole program. In summary, SUE is a viable engineering practice that reduces risk-related project costs that are associated with sub- surface utilities. SUE is most effective when adopted by an agency in a systematic manner and introduced early in the design stage. The greater a designer’s familiarity with valuable SUE data and with the ways in which this data can support the optimization of the design, the higher the agency’s monetary return. What becomes of SUE data at the conclusion of a proj- ect is a matter that remains to be addressed. In most cases, after its intended use, much of the SUE data that has been collected is effectively lost. The benefit-cost ratio of quality level B and quality level A SUE data could increase if such data were trans- ferred into one or more common databases and archived by the sponsoring agency to support future planning and design activities. Recent Study Recommendations Safety-, disruption-, and cost-related concerns surrounding damage to buried utilities and pipelines have escalated in recent years, leading to initiatives and studies addressing util- ity damage prevention and utility locating technologies. In the local utilities sector, the relationship of utility characterization technologies to condition assessment and asset management has received the most attention recently. In the pipeline sector, the emphasis has been on inspection methodologies for pipe- line condition and on the safety and monitoring of unautho- rized pipeline intrusion. Some of the more authoritative reports and their recommendations are summarized in the fol- lowing paragraphs to offer background and further support for the recommendations made in this report.

53National Research Council Report: Seeing into the Earth A National Research Council (NRC) Committee of the Board on Earth Sciences and Resources was formed in 1995 with the specific tasks of (1) assessing current capabilities for charac- terizing the near-surface environment using noninvasive tech- nologies, (2) identifying weak links in current capabilities, and (3) recommending research and development to fill these gaps. NRC committees are carefully assembled on the basis of individual expertise and a collective balance of viewpoints; hence, their recommendations carry significant weight. In the committee’s examination of R&D efforts, it looked at recom- mendations to address why available and adequate methods for undertaking many tasks are not being practiced more widely. The committee’s research recommendations are as follows (7): • Scientists and engineers should improve the integration of multidisciplinary data for modeling, visualizing, and under- standing the subsurface. • Government agencies should be encouraged to increase their investments in near-surface characterization R&D in areas appropriate to the mission of each agency. • Government and industry should cooperatively investigate coordination mechanisms and support site-characterization research and development. • R&D efforts applied to automation of data acquisition, data processing, and decision making should be given a high priority for research funding because they could produce rapid improvement in all aspects of near-surface characterization. • Where monitoring is required, noninvasive measurements taken over a prolonged time period should be investi- gated as a possible monitoring method for site character- ization, underground construction, and remediation projects. • A basic research program should include a significant effort directed toward quantifying physical and chemical realities of what is sensed and toward possible interactions between in situ properties and processes. • Long-term research to develop new noninvasive tools and techniques should be given a high priority, with emphasis on research done by multidisciplinary teams. Many of these recommendations focus on near-surface geotechnical or geoenvironmental investigations rather than specifically on utility locating. However, the importance of this topic, the need for expanded R&D, the need to involve mission agencies, and the committee’s recommendation to emphasize multidisciplinary teams mirror this report’s conclusions. The strongest R&D-specific recommendation that could producerapid improvement is in data acquisition, data processing, and decision making. The committee’s practice-related recommendations are as follows: • Government agencies, environmental and engineering con- tractors, and university researchers should work to analyze and document the potential costs and benefits of the use of noninvasive characterization methods in a wide variety of applications. • Government agencies (federal, state, and local) need to develop approaches to site characterization that focus on flexible program design procedures and decision-making processes that account for the unique character of each site. • Scientists and engineers have to place greater emphasis on communicating information about noninvasive tools and techniques and their recent advances to practitioners. • Government agencies and professional societies are encour- aged to form partnerships in long-term efforts to distribute and share information on the capabilities and recent devel- opments of noninvasive characterization methods. Again, these recommendations are intended to cover the broad needs of all near-surface characterization, but they echo familiar themes in other reports on utility locating—namely, the need to show the cost-benefit of improved techniques and better investigations, the need for flexibility in funding accord- ing to risks associated with a site or a utility, and the need to communicate current capabilities. Another committee recommendation, that of integrating multidisciplinary functions, is in fact the model for the subsur- face utility engineering field, in which professional engineers, surveyors, and geophysicists work together to find, portray, and analyze existing utility information. The NRC report has specific recommendations concerning potential advances for various characterization methodologies, such as field electrical methods, seismic methods, and ground- penetrating radar. These recommendations have been incor- porated into this report as appropriate. Initiatives of the Office of Pipeline Safety, Pipeline Hazardous Materials and Safety Administration Since the early 1990s, the Office of Pipeline Safety of the Pipeline Hazardous Materials and Safety Administration (OPS/PHMSA) has increased programming both to require safe operations by pipeline operators and to fund targeted research aimed at improving the technology related to pipe- line damage prevention and detection technology. The pro- grams restrict their focus to pipelines rather than cables, and

54important tasks include detection of pipeline encroachment and mechanical damage by third parties and pipeline locat- ing and condition assessment. Areas of research that are cur- rently being funded can be found at http://primis.phmsa. dot.gov; typically, a request for white papers is issued each year from which projects are chosen for full proposal prepa- ration and potential funding. While OPS/PHMSA has a specific mission relative to pipe- line safety, many of the utility detection and encroachment technologies, condition assessment technologies, and map- ping and recordkeeping technologies are relevant across the range of buried utilities. Although differences in the pipe size and layout, available funding, and safety implications of haz- ardous material pipelines mean there are some problems in technology crossover, there is also significant overlap in the core problems to be researched across the utilities. Gas Technology Institute In March 2006, the Gas Technology Institute/Geosynthetic Research Institute (GTI/GRI) released a final report by Pro- cess Performance Improvement Consultants, LLC, titled A Compendium of Practices and Current and Emerging Tech- nologies to Prevent Mechanical Damage to Natural Gas and Hazardous Liquids Transmission Pipelines (8). According to the report, while the technologies used to prevent mechan- ical damage differ in many regards from conventional util- ity detection technologies, there are many overlaps in practice and similarities in research needs. The report provides rec- ommendations in four areas: recommendations derived from historical safety-performance analyses, improving one-call effectiveness, the role of work practices in preventing mechan- ical damage, and the role of technology in preventing mechan- ical damage. The description of locating technologies for the most part refers to the CGA reports (9, 10), which in turn cite the 1999 Statement of Need and 2000 Summary of Responses (11, 12) in regard to potential technologies and desired performance. The findings and recommendations of the GTI/GRI report most relevant to the current study are as follows: • Additional strengthening of the one-call system is needed. • Fewer accidents are being caused by previously damaged pipe. (That is to say, partial mechanical damage is being detected before a major incident occurs.) • Better data on the causes of incidents is providing greater insight on how to prevent them. Some states do not mea- sure damage-prevention performance. • Exempt entities account for about one-quarter of the third- party-related pipeline incidents.• Effective programs supported by strong regulation and enforcement can yield a dramatic decrease in damage to underground facilities. • Options to reduce miscommunication include “positive response” and expansion of the role played by one-call centers to include collecting responses from utilities and providing a single set of responses to excavators. The report presents 116 practices to enhance damage- prevention programs and develop integrity-management programs. They include the following: • Practices and technology need to be considered in concert. • There is a need for an ongoing commitment to study and evaluate pertinent technological developments in other fields. • There is a need for periodic industry forums. • Map integration would put all utilities on a unified, com- patible base map. • Lack of precision in one-call requests results in unproduc- tive locating work, which diverts resources away from more productive prevention work. Initiatives of the United Kingdom Water Industry Research/American Water Works Association Research Foundation As indicated elsewhere in this report, the United Kingdom has initiated several major R&D programs to deal with streets/ highways and utilities. Problems addressed by the programs include the major effect of street work on traffic congestion, and the risks and costs associated with not knowing the loca- tion of underground facilities and not having the technology to effectively carry out buried-utility location. A major program entitled Mapping the Underworld emerged from this concern, as did a series of issue-identification and R&D-planning activ- ities. The UKWIR has been driving this work with support pro- vided by AWWARF. The results of the major activities and the conclusions about innovation in locating and characterizing utilities that were reached are briefly reviewed here with refer- ences to the source documents. By way of background, in May 2002, a three-day workshop on multi-utility buried pipes and appurtenances location was held in London. The workshop included 27 delegates from the United Kingdom, the United States, and the Netherlands with varied disciplinary backgrounds and job functions. The work- shop discussed the industry’s needs, the current technologies that are available, and the gaps that exist between the needs and the current technologies. Discussions resulted in 28 high-level proposals for future innovation, which were then prioritized

55by potential benefits and rationalized into 16 proposals for further development after the workshop. The estimated cost of the research identified in all proposals totaled $13.3 million. The 16 proposals for further development were as follows: • Methodology and standards for utility asset-location data collection and exchange; • Smart-pipe technology; • Methodology for determining total costs for construction, operations, and maintenance of buried infrastructure, and use of total costs of mislocating buried infrastructure to justify—or not—investment in improving locating tech- niques, equipment, and GIS-based mapping; • Asset tagging; • Develop a multisystem location system—three-phase project; • Improve GPR performance; • Employ smart pigs for location of adjacent buried infra- structure; • Determine feasibility of using horizontal sensing to deter- mine depth of buried infrastructure; • Develop “see ahead” technology; • Develop novel approaches to traditional underground infrastructure; • Develop new technologies for underground asset location— capability review; • Provide quality training; • Conduct requirement analysis of user needs; • Progress toward a better regulatory framework for buried infrastructure management; • Develop techniques to detect existing small nonferrous buried assets; and • Categorize the utility environment. Again, these recommendations closely mirror the findings and assessments made by the current study participants. Utility Locating Improvements This section identifies the most promising technological devel- opments relative to utility location and assesses their potential and appropriateness for further acceleration using SHRP 2 funds. Active Technology Developments Chapter 4 reviewed the range of potential methods for buried- utility locating and the current state of practice. This section seeks only to identify those methods that either are under- going significant enhancement or that have the potential to besignificantly enhanced through further R&D investments. The focus of this discussion is on the R&D activities under way through publicly funded research projects or through consor- tia that report on their activities in general terms, if not in spe- cific details about the intellectual property achieved through such research. A brief review of research items that are of par- ticular interest to this report follows. This discussion is not meant to reference every effort. Advanced research for partic- ular technologies may be under way at private companies or research laboratories not mentioned here. However, based on the literature that has been reviewed, patents that have been searched, and discussions held over the course of this project, it is believed that the items reviewed are representative of the ongoing research efforts. AWWARF/OTD/GTI Partnership Program The partnership among AWWARF, Operations Technology Development (OTD), and GTI is explained by its name: Underground Facility Pinpointing—Finding a Precise Locat- ing System for Buried Underground Facilities. The second phase of this program was under way as of this writing. This phase includes further investigation of emerging technologies such as capacitive tomography, radio frequency vibration, acoustic pipeline locating, and visualization technologies. However, the key elements of the program are to conduct field demonstrations of locating technologies to find nonmetallic pipe, especially polyethylene pipe. The demonstrations will be conducted in different parts of the country to better establish the conditions where GPR is effective. The report is to contain analysis of the performance data of the various devices, together with specific strengths and weaknesses and possible future research and development. Acoustic Pipe Locator The acoustic locator has been developed by GTI and was due to be released in 2008. About 300,000 mi of plastic pipe have been installed without tracer wire in the United States alone and between 500,000 and 1 million mi of it have been installed across the world. The technology was patented in February 2004. A field test indicated the method could detect a 1.25-in. plastic pipe at depths of 3 ft to 4 ft. At a depth of 4 ft, this is about a 36-to-1 depth-to-diameter ratio. Complexities that may affect the efficiency of the method include soil density variations, utility trenches, and side reflections (13). Locatable Plastic Pipe Developed by GTI, the pipe is composed of magnetized stron- tium ferrite particles that were incorporated into the pipe

56during manufacture. The particles are 12% to 24% by weight, but only 3% to 4% by volume. Locating is effective for pipes of 4 in. in diameter and larger. GTI has been working to increase the signal strength for locating purposes. The pipe has been approved by ASTM but needs federal code approval (14). Witten Technologies Witten Technologies, Inc., has been involved in developing and commercializing arrayed remote sensing technologies since the late 1990s. It has developed GPR sensor arrays (in collaboration with Mala Geoscience as the GPR supplier) that provide sufficient data for the tomographic reconstruction of buried objects found beneath the ground surface. This data is then exported to 3-D CAD or GIS software for database storage and 3-D visualization. The technology built on earlier tomography algorithms developed over several decades by Schlumberger for the oil exploration industry. Since 2000, Witten reports that, in addition to its investments, nearly $2 million in third-party research has gone into the develop- ment of the system. Funding contributors have included the Electric Power Research Institute (EPRI) and GTI for the development of computer-assisted radar tomography (CART), which has been fully commercialized since the turn of the century. More recently, USDOT/OPS/PHMSA and Consoli- dated Edison participated in a project to merge the CART array with an inductive array to introduce a digital mapping of buried pipelines with a dual array system (http://primis.rspa. dot.gov/matrix/PrjHome.rdm?&prj=109). The arrays were not commercially available in 2005 but were considered close to commercialization. Witten has also collaborated with NASA’s Jet Propulsion Laboratory (JPL) to use JPL’s expertise in advanced radar image analysis to sharpen the tomographic images and identify linear features, such as utility lines near the limit of resolution of the radar (15). Underground Imaging Technologies, Inc. Underground Imaging Technologies, Inc., (UIT) has been in business since 2002. The company formation was initiated when the Arizona Public Service (APS) Company issued a request for proposals to develop a hardware and software system to map utilities of any material type in any soil. APS entered into a joint venture with Vermeer Manufacturing for development and commercialization of such a system. Based on R&D expenditures in the multimillion-dollar range, and funded entirely as equity capital, UIT entered the mar- ketplace with a GPR unit known as TerraVision. This GPR unit was developed in partnership with Geophysical Survey Systems. The integrated UIT system includes a multisensor time domain electromagnetic system based on the Geonics EM-61 instrument. Deploying these two systems separately or together, UIT has completed numerous projects with cus-tomers such as Consolidated Edison, Shaw Group, and New York State DOT. The UIT system includes proprietary software products called DAS and SPADE that support the acquisition, processing, visualization, and interpretation of multiple sensor data and of supporting data in a 3-D workspace. UIT remains committed to ultimately meeting the original goal of work- ing in any soil type, and it has self-funded the development of a prototype multiple-source receiver seismic tomographic system. R&D efforts to attain the needs of commercial appli- cations are still under way. Forced Resonance Radar Bakhtar Associates is adapting underground-sensing tech- nologies developed for landmine and unexploded ordinance detection to pipe-locating systems. The system uses a propri- etary forced resonance radar and associated signal processing to detect buried objects and to provide an improved signal- to-noise ratio. The claimed advantages for the system are the abilities to resolve images in conductive soils, to detect small- diameter plastic pipes, to differentiate between materials, and to determine the diameter and depth of pipes (16). The BakhtarRadar system also uses a high-accuracy GPS unit (horizontal-position accuracy under 0.4 in.) to record the location of detected anomalies, and it is capable of 3-D image reconstruction with dimensional details. The BakhtarRadar system was tested in two of the Gas Tech- nology Institute’s test beds, the clay test bed and the silty-sand test bed, reportedly with positive identification results. The report indicates that the system was “able to locate small diam- eter plastic pipes in a highly conductive soil. Additionally, accurate depth and diameter information was acquired.” The report also characterizes the stage of development of the utility detection system as follows: “The EarthRadar system is not currently in a format compatible with the utility industry’s needs. The system is large and awkward and the software requires interpretation and processing. Further development is needed to transform the existing system into a rugged and user-friendly device that utilities can use to locate underground facilities. To gain the performance indicated, the current system needs to be calibrated or tuned for particular soil conditions.” Information from Bakhtar (17) provides 3-D image reconstruc- tion of the pipes placed in the clay test bed. These pipes were a 2-in. diameter plastic pipe buried at a depth of 2.6 ft and a 4-in. diameter plastic pipe buried at a depth of 7.4 ft. A 2-in. pipe at 2.6 ft represents a depth-to-diameter ratio of 15.5 and a 4-in. pipe at 7.4 ft represents a depth-to-diameter ratio of 22. NYSEARCH This commercial collaboration is focused on detecting buried utilities through a technique that has been termed “Hyper- Radar.” This approach uses a low frequency to gain depth

57penetration for GPR even in problem soils while using signal- processing techniques and stepped frequencies to enhance signal-to-noise ratios and increase the resolution with which utilities and other buried targets can be identified. Several independently documented field trials have been carried out using this technology, which has shown improved success in identifying buried utilities with high depth-to-diameter ratios or in problem soils such as conductive clays. At the time of the writing of this report, the first commercial systems were reported to be soon available to the marketplace. Ingegneria dei Sistemi SpA Ingegneria dei Sistemi SpA (IDS) has been involved in the development of tomographic GPR arrays for utility designa- tion since 1990. One of its key attributes was the use of a “dou- ble threshold detection” radar approach in which detection of an object against background noise, particularly a pipe against localized objects or noise, could be significantly improved on by noting the same level of echo in the same position in multi- ple scans. Recently, IDS has been a key partner in the GIGA project (see chapter 2 for description). The GIGA approach has been to focus on three main research axes related to the basic performance of the radar detection: (1) radar technology improvements; (2) multiparameter/multiconfiguration data fusion and data processing, based on flexible GPR measure- ments in close relationship with modeling and simulations; and (3) specific radar and signal-processing algorithms to improve the discrimination between the object to be detected and interfering signals. At the end of 2003, the GIGA project, which is valued at €3 million (∼US$4.5 million), was completed. A new project is now under way to design, develop, and test a new, specific GPR demonstration prototype. Testing of IDS equipment was car- ried out in autumn 2002 at the Gaz de France test site in Saint Denis, Paris, France. The goals of the test were to measure the probability of detection and false alarm rate, accuracy of loca- tion in the horizontal plane, accuracy of location in the verti- cal plane, range of depth, and resolution of multiple objects in the horizontal plane. Five equipment configurations from IDS were selected for testing. The results from the testing were reported by Manacorda et al. (18). Some limitations in detection rate and range depth were encountered in the presence of highly con- ductive soils; however, in these areas, tested configurations detected more than 70% of the existing pipes, mainly as a result of the combined use of high- and low-frequency antennas. In pits with lower signal attenuation and where traditional buried pipe layouts were simulated, 100% detection performance was possible. The data analysis provided good accuracy in deter- mining horizontal and vertical position with an averaged error in determining the utilities’ depths of less than 1 in. Thismatches the relevant end-user requirements as determined by a survey of 170 European utilities. Promising results were also noted when using innovative processing techniques such as 3-D migration and polarimetric processing. Simulation work by IDS in connection with equipment development is adapted from the transmission line matrix modeling (TLM) approach and from another GIGA partner (Thales Air Defense) that uses optical propagation laws and the Descartes and Huygens laws. Both approaches avoid the com- putational load of solving the full Maxwell equations and are reported to provide good results with greatly reduced compu- tational time. The simulation work is intended to fix the real physical limit of the pipe detection under different site condi- tions and to select the antenna and radar characteristics to match the operational requirements set by the end user. In the conclusions of their paper, Manacorda et al. assert that an enhancement of the state of the art of underground mapping tools is possible and that in the near term it will be possible to some extent and in the medium to long term it will be entirely possible to match the demanding requirements of the survey, as carried out at the beginning of the GIGA project. The spe- cific requirements being targeted, however, are not defined in the paper. Mine Detection Considerable work in buried-object detection is being carried out in the area of mine detection. It has been estimated that, at the current clearance speed, it will take more than 100 years to remove all the landmines that remain in the world (19). Mine detection is based on differences between the mine and the sur- rounding ground, as in buried utility detection, but it may also be based on the detection of either outgassing from the plastic used to construct the mines or outgassing or nuclear resonance from the explosive material itself. A research program has been under way for several years in Japan to construct a combination of either stepped-frequency GPR or impulse GPR with metal detection (MD) and to deploy the detection system in rugged terrain (20). While significant work is being done in this area, the range of depth for mine detection is typically up to about 1 ft; hence, successful mine detection approaches may need adaptation or verification for deeper applications or may simply not be applicable. Results from field test comparisons of developed systems to metal detection only indicated that GPR+MD could improve the probability of detecting targets at a depth of around 8 in., where MD detection only becomes difficult. It was also found that the positioning control of the sensor head needed to be improved. Mapping the Underworld This major U.K. initiative was discussed in chapter 2, and its research goals were outlined earlier in this chapter. Because the

58goals of the research initiative closely mirror those of SHRP 2, it is possible to build complementary rather than duplicative research activities. The aim of the MTU Location Project is to investigate the feasibility of several novel approaches, alongside greatly enhanced approaches, to be combined in a single multimodal approach to locate, identify, and possibly assess the condition of buried assets, whether deployed from the surface or sub- surface from within an existing utility conduit. The objectives of the research are as follows: • To determine the capabilities of existing technologies and the potential of novel technologies to locate and identify buried utilities under three broad headings: GPR, acoustics, and low-frequency electromagnetics. • To explore in detail the most promising technologies for integration into a single multi-utility device. • To produce a fundamental understanding of the limita- tions of signal propagation through and reflection from the underground media encountered in the above operations (that is, bound and unbound pavement structures, soils, pipes, and the materials that they carry). • To explore the feasibility of combining the techniques to create an integrated, multisensor device. • To explore the feasibility of deploying the multisensor device both from the surface and from a pig that travels through an existing buried conduit. • To conduct a survey of relevant industrial stakeholders to determine the accuracy requirements of such a technology. This project is nearing completion and has achieved its goals. Other Commercial R&D Activities As mentioned earlier, the preceding identification of specific research activities is not intended to indicate that this review comprises the only innovative research under way in the field of utility locating. The identified activities were collected through the literature search, the statement of need process described in chapter 2, and contacts by project team members with companies and organizations related to utility locating issues. Although extensive information-collection activities were conducted as a part of this research, this report has not attempted to categorize the R&D activities of all the companies in the field. Current methods in use are reviewed in chapter 4, and a database of methods and selection software is pre- sented in electronic form in an accompanying product. Appendixes A and C also provide contact information formany companies and organizations related to utility location and characterization. Many commercial development activities are following sim- ilar avenues of development to the approaches outlined above even if the signals used or the specific approaches vary. Technological Areas of Improvement This section summarizes the most promising avenues for tech- nological improvement with respect to utility locating. Map- ping and marking issues, procedural and funding issues, and education and training needs are dealt with in separate sec- tions. Descriptions of the technology and the current state of the art have been introduced in earlier chapters. This section lays out the key areas that have been identified, including a brief justification for this selection. Many technologies come with a best range of applications—either in terms of target util- ities or site conditions. Hence, for many issues, it is not prac- tical or justifiable for the authors to select one particular technology over another, given the wide range of needs, the limited availability of performance data, and the natural reluc- tance on the part of the companies to release intellectual property. However, the authors believe that it is possible to establish the most promising technological directions and to establish guidelines for targeted research funding that will have the greatest short- to medium-term impact on techno- logical development. The avenues for improvement are discussed under several key headings that are not necessarily comprehensive but that do cover the most critical needs for locating improvement and the approaches being developed. Deep Utilities Finding undocumented utilities, without ancillary detective work, at depth-to-diameter ratios greater than 20 to 1 (that is, a 3-in. utility at a depth of 5 ft, or a 1-ft utility at a depth of 20 ft) has reached the limit of theoretical expectations for surface-based surveys, even under soil conditions considered reasonably fair for most surface geophysical methods. Radio- frequency methods, where the target is a significantly better conductor than the surrounding environment, can increase depth-detection capabilities. Practical expectations for detec- tion are closer to a 12 to 1 depth-to-diameter ratio. Also, when a utility is deeper, there is a greater chance that soil variations and other utilities or objects at shallower depths will mask the presence of the deep utility. Multisensor approaches can com- pensate for some soil environment difficulties (for example, acoustic techniques will work in conductive soils where GPR is effective only at very shallow depths), but for the foreseeable future there are optimistic expectations for finding unknown

59utilities of various sizes at depths exceeding 15 ft to 20 ft through surface investigations. Passive surveys use natural random vibrations and can image the zonation of deeper materials through statistical analysis and inversion techniques. However, low-frequency signals are not useful for detecting small and moderate-sized utilities. One key utility-detection component involves introducing an energy source through the ground to the utility. Energy dissipates both when it travels through the ground and when the reflected signal returns to the detector. Both direct connections to the deep utility and the introduction of an energy source closer to the deep utility, such as through a borehole, can be effective in some cases. Locating deep utilities has received attention in the context of deep tunnel detection, for example in regard to finding tunnels across the demilitarized zone in Korea or across the Mexico-U.S. border. Detection of tunnels at depths of 80 ft and more has been achieved (21), but most trials have been in open country and many involved additional items within the tunnel for detection (such as electric lighting circuits). Such tunnel detection often occurs in favorable soil conditions and in a “less noisy” detection environment. Tunnel detection is currently receiving significant atten- tion from the Departments of Defense (22) and Homeland Security, which have issued RFPs that will initiate or continue research funded in the range of several million dollars (23). The work being done to address tunnel-detection problems should be tracked closely for results that will aid in the detec- tion of deep utilities in urban areas. The most promising avenues for addressing the problem of deep utilities in urban environments are as follows: • Multisensor approaches to increase the reliability of recog- nition and performance over a range of soil conditions; • Stepped-frequency and signal-to-noise ratio improve- ments to increase the depth-to-diameter performance; • Soil-characteristic surveys to optimize the detection-method parameters for deep utilities; • Sewers, which are typically below most other utilities, or drilled or vacuum-excavated boreholes employed for direct path scans or reflection scans from a deeper horizon; • Cross-bore tomography use of boreholes to identify deep utilities—for example, using conductivity surveys, direct- path electromagnetic, or seismic signals; • Test-hole use to provide a direct access connection to the pipe, eliminating half of the total ground attenuation; • Extensive records research to identify potential deep utili- ties in an area; • Statistical or pattern recognition techniques to improve recognition of specific types of targets; • Identification of a feature within a deep utility or tunnel that can be more effectively traced than the structure itself;• Continuous mapping and database development for utili- ties (see separate discussion); • Rigorous as-built documentation requirements (see sepa- rate discussion); and • Last opportunity see-ahead approaches to help prevent actual utility strikes (but this does not help in terms of locating for planning and design purposes). Nonconducting Utilities Nonconducting utilities, such as those made from plastic or clay or those that do not provide a potential continuous cur- rent path, are inherently difficult to locate unless they have been clearly marked using locating tape or wire, marker balls, or other marking techniques, as discussed in the section on utility marking. If the interior of the utility is accessible, then acoustic signals, a conductive trace cable, or an electromagnetic sonde can be introduced into the pipe to aid in locating. How- ever, unrecorded, nonconducting utilities do exist and will only be found if the locating technology can detect the presence of the utility within its ground environment. “Cast-in-stone” project limits may preclude a surface investigation that would identify a remote access point where a conductor or sonde could be introduced. With the large increase in the amount of plastic pipe being installed, the small diameters often used, and the unrestricted depths offered by installation techniques such as horizontal directional drilling, detection of nonconducting utilities at high depth-to-diameter ratios is high on the list of technological needs. Unfortunately, there are significant theo- retical limitations, such as depth-to-diameter ratios, and prac- tical limitations, such as congested utilities, layered utilities, and pavement structures, to what can be detected using cur- rently identified approaches. The most promising avenues for addressing the location of nonconducting utilities are the following: • Further development of GPR and acoustic technologies for surface-based utility locating (shallower utilities and larger diameter utilities at depth); • Longer and more efficient cable insertion equipment and improved techniques; • Major improvements in marking and mapping approaches (see separate discussion); and • Last opportunity see-ahead approaches to help prevent actual utility strikes (but this does not help in terms of locat- ing for planning and design purposes). Congested Utilities Congested utilities and other interference-producing condi- tions mask the individual signals from various utility-detection

60approaches and provide a low signal-to-noise ratio. The close horizontal separation of utilities can be addressed to a certain extent using narrowly focused signals, but the identification of vertically stacked utilities is more difficult. Surface-based tomographic approaches can provide some advantages, partic- ularly with multisensor arrays. Surface tomography extensions can include surface-borehole or cross-hole approaches that allow direct-path methods of assessing utility targets. Direct- path methods that transmit or receive signals between a deep horizontal pipe and the surface could provide additional reso- lution of multiple utilities. This also was discussed in the pre- vious section on deep utilities. The cost of nonsurface-based technologies and the potential that a borehole may cause util- ity damage are significant limitations to the broad use of these approaches—particularly in the planning stage of a transporta- tion project when the alignment of or funding for the project is uncertain. Vacuum excavation may be explored as one way to eliminate damage related to boreholes. The most promising avenues for addressing the problem of congested utility areas follow: • Surface-based, multisensor, tomography approaches; • Enhancements to existing equipment that would make direct connections to utility systems easier and more efficient; • Stepped-frequency and signal-to-noise ratio improvements; • Sewers, typically below most other utilities, or purpose- drilled horizontal boreholes for direct-path tomography; • Continuous mapping and database development for utilities (see separate discussion); and • Further definition of the ability of various techniques to dis- criminate closely spaced utilities (this may not matter for damage prevention but may be very important for design). Unfavorable Site Conditions Unfavorable site conditions include the presence of highly con- ductive soils that limit GPR application and the presence of objects that distort the electromagnetic fields used in conven- tional locating. Such conditions also include extensive utility congestion and access conditions that prevent adequate surface surveys, such as physical or traffic restrictions. Ground surface and subsurface rigidity may affect acoustic methods. Utility-detection techniques can often be tuned to optimal frequencies, antennas can be designed for specific site condi- tions, and error-producing conditions can be identified to allow a locator to compensate for such difficulties. Site con- ditions may also change with time; for instance, there is a need to deal with changing soil conductivity caused by salt use on roadways. The most promising avenues to address the problem of unfavorable site conditions are as follows:• Surface-based, multisensor, tomography approaches; • Stepped-frequency and signal-to-noise ratio improvements; • Site condition and soil characteristic surveys that help to establish the most effective locating methods and param- eters on a local or regional basis—for example, soil conduc- tivity maps related to GPR applicability; • Improved recognition of error-producing conditions; • Sewer use (typically below most other utilities) or purpose- drilled horizontal borehole use for direct-path tomography; • Continuous mapping and database development for utili- ties (see separate discussion); and • Seasonal imaging and documentation (in cold climates) of certain utilities when the ground is rigid (frozen). Mitigation of Practical Limitations on Theoretical Performance This approach looks at the fundamental physics that govern the operation of various locating methodologies, and it seeks to optimize each aspect to more closely approach detection- capability theoretical limits. It is necessary to simulate the per- formance of the detection method in a geometrically complex environment to ensure applicability over a wide range of soil conditions and target utilities. The practical limitation on the performance of tuning meth- ods in specific conditions is that they are unlikely to function as well as a general purpose technique. To achieve a benefit of tuned performance over a wide range of applications, it is nec- essary to adjust the detection method in a simple and cost- effective manner as it is used in the field. However, as a result, equipment costs will increase and more high-level site input to the detection process may be necessary. The most promising avenues to address the mitigation of practical limitations on theoretical performance are the following: • Multisensor approaches to increase the reliability of recog- nition and the performance over a range of soil conditions; • Stepped-frequency and signal-to-noise ratio improvements to increase the depth-to-diameter performance; • Soil-characteristic surveys to optimize the detection method parameters; • Statistical or pattern-recognition techniques to improve recognition of specific types of targets; and • See-ahead approaches that reduce the need to see large dis- tances through the ground. Multisensor Approaches Multisensor approaches have been identified as potential solu- tions to all of the issues raised thus far. The commercial appli- cation of such approaches, however, requires that the increase

61in performance justifies the increase in equipment and oper- ating cost. This, in turn, requires that an increase in perform- ance is properly valued against the risk-based cost of poor detection that may result in project delays, cost overruns, and personal injury. The most promising avenues to address improvements to multisensor approaches are the following: • Combinations of electromagnetic induction sensors (con- ventional locating instruments) with GPR approaches to enhance conventional locating practices with the ability to image nonconducting or unidentified utilities; • Combinations of acoustic and GPR approaches to provide acceptable performance across ranges in soil conductivity and rigidity; • Spatially varied sensor arrays and stepped-frequency approaches to provide improved target recognition and signal-to-noise ratio improvements; • Adoption and extension of available research on sensor fusion and recognition of targets (for example, mine- detection research and other military-related applica- tions); and • Development of methods to combine information from dif- ferent approaches (for example, hard and soft data), taking account of different reliabilities (24). Target Recognition, 3-D Location, and Transfer to GIS/CAD There is still significant room for improvement in approaches to target recognition and reconstruction, estimation, and con- firmation of the depth and horizontal position of a utility and in how this information is transferred to computer databases and visualization software. Currently, the only way to gain real confidence in an accurate position and the type of utility is to expose it via test holes. This approach is likely to remain the preferred way for a long time, but it is time-consuming and costly. It would be of great benefit to be confident of gaining positional accuracy without excavation. The most promising avenues of improvement in regard to this issue are the following: • Continued research on inverse approaches to target recon- struction; • Continued research on signal-processing enhancements and statistical and expert system/neural network approaches to identification of unknown targets and known targets with specific characteristics; • Automated and rapid means of transferring belowground positional information into GIS coordinates (see mapping discussion);• Improved sensor fusion in combination with other soft or hard data as outlined above; and • Statistical reliability analysis through correlation of test- hole data with surface geophysical data. Developing Additional Approaches Conductivity mapping remains under development for near- surface investigation applications. Multichannel analysis of surface waves is reported to offer great promise for determin- ing the engineering properties and zonation of near-surface materials (25), but it is probably less effective in terms of util- ity location. Various other approaches, such as the use of ran- dom earth vibrations mentioned earlier, may find application to certain investigation problems, but the bulk of utility- locating practice is likely to remain with electromagnetic pipe and cable locators, GPR, terrain conductivity, magnetic detec- tion, and acoustic detection. Various combinations of these approaches may also be adopted. It is worth remembering, however, that changes in electronics and computing power can lead to significant changes in what is possible for each technology in terms of speed and cost, manpower require- ments, attainable resolution, and so forth. Thus, the techni- cal landscape does not remain static over time and periodic reassessment is needed. The recommended actions in regard to additional approaches are as follows: • Regular technology reviews to assess changes in the techni- cal landscape and emerging methods. This would also serve to keep the issues and the latest technologies in front of DOT decision makers and other transportation project designers. • Use of existing and newly constructed test facilities to doc- ument the capabilities of utility locating equipment under controlled conditions of varying complexity. • Creating a grand technology challenge with regard to locat- ing deep utilities in a poor soil environment. Such a chal- lenge could serve to publicize the technology needs to the general public, to those who make decisions about the fund- ing of utility investigations, and to the broader research community that is not currently involved in utility-location technology research. • One cross-cutting need in the utility-locating arena is mak- ing the equipment usable by people other than highly spe- cialized engineers and scientists to ensure broad acceptance and cost-effectiveness. This does not necessarily reduce the need for an expert to direct SUE-style utility locating and mapping activities, but it would lessen the costs of deploy- ing advanced technologies at a site. • Improvements in direct-connection devices, such as signal coupling methods, for pipe and cable locators are necessary.

62Such devices will tend to be used if available and will enhance the detection of deep utilities and assist in discrim- inating between braided and stacked utilities. • Technological advances in locating are an ongoing process, but advances are useless in practice until the client considers them to be cost-effective. Methods and documentation of true utility costs on projects need to be developed. Utility Characterization Improvements Improved methods of utility characterization are desired so that, with an ideal set of technologies, the same survey that would pinpoint utility location would also provide the key operational and condition characteristics of the utility. This information, in turn, would allow timely decisions to be made when working in proximity to the utility concerning safety issues, the utility’s operating condition, its expected longevity, and the potential for future interference with the renewed highway pavement. To be most effective, this characterization information cannot be left until the construction phase. It is needed during the planning and design phase of the highway project. In the construction phase, characterization informa- tion is primarily used for previously undiscovered or inacces- sible utilities. Any problems identified at this stage are almost certain to cause project delays and cost increases. As discussed earlier in the report, the primary characteristics of the utility include its size, material, purpose, ownership, age, and usage status, which is to say whether it is inactive, aban- doned, out of service, or active. Some of these attributes could potentially be found from surface investigation methods or from nondestructive or minimally destructive external evalu- ations of an identified utility service. But most would normally be found from utility records once the utility has been identi- fied. This attributing process from records is standard proce- dure within the quality assurance process, such as that used by the SUE professional, but it rarely occurs when utility mapping responsibility is fragmented. The additional desired informa- tion is primarily related to the utility’s structural details (wall thickness, joints, splices, encasement, coating, cathodic pro- tection) and condition (corrosion, physical damage, signal fault, and so forth). It should also be noted that internal inspection of pipes can be used to provide accurate 3-D loca- tion information. The wide variety of information types, the detailed proce- dures used to gather different data when a utility is physically accessed, and the limited number of technologies available to gather the data in a remote fashion make it difficult to discuss advances related to each characterization need. Instead, the potential advances are discussed below under broader head- ings that relate to the timing of the information collection and accessibility to the utility.Active Technology Developments Chapter 5 reviewed the state of the art for a variety of utility- characterization activities. As discussed in chapter 5, most of the research activities seem to be in the areas of pipeline condition monitoring, mechanical damage prevention for pipelines, and internal inspection technologies coupled to general asset management for buried utilities. Examples of cutting-edge technologies that continue to be refined include the following: • Multisensor inspection platforms (smart pigs); • Multisensor dimensional and condition assessment infor- mation; • Laser point cloud internal pipe dimension analysis, which when correctly registered can provide information on pro- gressive deformation of pipe systems; • Ultra-wideband (UWB) scanning for pipe wall defects and external voids; • Passive marking and RFID tagging of utilities; • Integrated CCTV, condition assessment, and asset manage- ment databases; and • Integrated systems used by municipalities and other utilities. Technological Areas of Improvement Characterization Information for Planning and Design The most promising avenues of improvement in regard to characterization for planning and design are the following: • More reliance on asset management databases held by the utility. Many utilities are conducting more regular inspec- tions of their assets, and condition-assessment tools, par- ticularly those than can be deployed within a pipe, are improving rapidly. Advanced fault-detection tools for elec- trical and fiber optic cables are also available that can detect the presence of faults and also provide their locations. • To integrate the above recommendation into a project- planning process requires identification and coordination of all the relevant utilities in terms of receiving condition infor- mation. It also introduces the question of whether utility companies, in return for use of the public right-of-way, will willingly cooperate (or will have a responsibility to cooper- ate) to assess utility condition before a new or renewal trans- portation project is constructed. Such issues are explored in more detail in the companion to this SHRP 2 report (26). • The recommended advances to be pursued in asset tagging and advance mapping and recordkeeping will also have a strong impact on the ability to retrieve important utility- characterization information when it is needed during proj- ect planning, design, and construction. • Acceleration of ongoing technical advances in condition- assessment technologies that can be deployed within pipes.

63Of particular interest for development are the technologies that track progressive deformation of pipe cross-sections with time, change in pipe-wall thickness, and the develop- ment of soil voids outside a pipe. For cables, fault identifi- cation and location are also important. Available Access to the Utility If SUE approaches are being used for planning and design purposes, then exposure of a utility to confirm its type and to record its 3-D position provides the opportunity to identify as many characteristics about the utility as possible externally. This considerably extends the range of utility characteristics that can be recorded. The two most promising avenues of improvement in regard to external characterization for planning and design are (1) techniques that can be used when a utility is exposed and that do not require tapping into the utility to gain useful infor- mation; and (2) preparation of a guidance or best-practices document that describes the procedures to be followed to investigate pipes or cables when they are uncovered. Some safety guidance exists, but a comprehensive treatment of pos- sibilities for practitioners seems to be lacking. Recordkeeping, Mapping, and Marking Many utilities that once had a known location often have to be found again. One-call systems and current locating practices are clearly much needed and have provided significant reduc- tions in utility strikes and significant improvements in worker and public safety. One-call systems will remain critical to damage prevention efforts at least for the foreseeable future, but it is possible to complement locating practices with increasingly reliable database information on utility loca- tions and characteristics. Fortunately, this is one area where there has been a radical change in technology and practice in recent years and this, in turn, provides a reasonable path whereby the circumstances of utility mapping and record- keeping can be radically changed. Marking technologies also have improved in recent years with potential for greater improvement through RFID tagging that is inexpensive and that allows significant information about a utility to be recorded and retrieved directly on site. The most promising aspects of mapping and database approaches and marking improvements, as well as the most significant barriers to be overcome, are discussed below. Active Technology Developments This is a very active area of individual technological advance- ment and system integration. Three examples are providedbelow to indicate the commercial research and development activity under way. ProStar Predator Software This is used for data collection and damage prevention. It uses the ProStar Grid—a precision land base that includes all available information, such as raster files of scanned topo- graphic maps, aerial photography, paper drawings, digital imagery, survey plats, metes and bounds, CAD files, and any vector graphic files. Existing data is aligned, molded, and shaped to fit key precision points that have been established for a proj- ect. It is a transaction-based system that allows changes to data to be recorded, and undone if necessary, and data “pedigree” to be noted in the system. It can operate in real time in the field and simultaneously in a remote office. It can also operate in a damage-prevention mode. The database can be centrally hosted, providing a variety of levels of secure access to differ- ent mapping and retrieval functions. TransLore This is a GIS-based system designed to automate many man- agement functions for one-call locates. The application may be hosted on the user’s server or on a TransLore server. Screening functions identify if a physical locate is needed for particular facility lines. 3M Dynatel 2200MiD Series Locating and Marking System This type of development system was mentioned in chapter 4. It is a system for field mapping and facilities maintenance that makes it possible to find a location and to confirm details of the buried feature before excavation begins so that workers know in advance what to expect (that is, where a utility has been repaired, as well as when it was placed and who did the work). Mapping and Database Technologies Currently, utility records are considered unreliable in terms of documenting accurate information on utility positions. Yet, the existence of technology to provide accurate geo-referenced positional information (high-accuracy GPS) and the wide- spread use of GIS platforms among utilities and cities provide the opportunity for change. Currently, operating systems that provide accurate, comprehensive utility mapping do exist. For example, in some areas of Japan all utility locations are plot- ted on a single utility-mapping system that allows for spatially correct 3-D information on buried utilities. The utilities are members of a consortium that shares utility informa-

64tion and commits to keep records up to date (27). Changes in approach are also being studied in the United Kingdom— for example, the Mapping the Underworld initiative—and in certain provinces of Canada. With fragmented utility ownership, concerns about compe- tition, particularly among telecom utilities, and security con- cerns related to unauthorized access to utilities or terrorist activities, there are many problems to be overcome. The authors of this report, however, believe that the further devel- opment of mapping and database approaches tailored to util- ity needs has a great potential to provide improvements in the design and construction of highway renewal projects and to assist in damage prevention. The recommended actions to address the aforementioned issues are as follows: • Continue to promote and teach the ASCE guidelines (28) as a means to standardize the collection and depiction of existing underground utilities on planning and design documents. • Select a number of transportation projects as demonstration projects for advanced mapping and utility management approaches. Closely document the benefits and problems encountered. This will serve to reinforce industry invest- ments in technology development and speed adoption in the marketplace. • Highlight the benefits of an accurate 3-D GIS database in terms of rapid response and recovery from natural and man- made disasters when physical landmarks are often hidden or obliterated. • Develop GIS applications to provide XYZ coordinates with a reliability and accuracy estimate for both horizontal posi- tion and depth. In the long term, this will lead to location probability that can be upgraded whenever new informa- tion about the utility is obtained. • Develop best practices for utility information databases, including the required positional accuracy for the proposed database developments (for example, New Jersey requires utility providers to map to a certain degree of accuracy, and Georgia DOT has received awards for its utility mapping program). The Common Ground Alliance has an active best-practices program. • Explore appropriate legislation, policies, funding restric- tions, and enforcement to provide a consistent landscape in which improved systems can flourish. Encouragement is probably not sufficient given the complexity of utility providers, issues, and needs. Utility Marking Technologies Utility marking presents important needs and new opportuni- ties. However, in practice, market forces alone are unlikely to result in uniform application of marking and pipe-locatingaids. To reiterate, conductive pipes and cables carrying electric currents are relatively easy to locate; nonconducting pipes and fiber optic cables are not. Locating can be enhanced by using cable sheathing or separate locating tapes or marker balls to identify the utility’s position. The principal drawbacks to sep- arate tapes or markers are that they may become displaced dur- ing later excavation and over time the continuity of the tapes is lost. For plastic pipe, research has been under way for several years to enhance the ability to locate the pipe itself by incorpo- rating magnetic filings into the plastic material from which the pipe is made. A key problem in the adoption of such a pipe appears to be that owners and contractors are unwilling to pay additional initial costs to put in place a pipe that is easier to locate in the future. RFID technology is rapidly gaining broad acceptance in industrial and commercial inventory systems. The sensors are inexpensive and can hold a significant amount of information for retrieval by scanners. The key application issue for buried utility systems is that of the signal transmission through the ground medium. As in the mapping and database area, this is a topic with significant potential for change in the near to medium term. The recommended actions in regard to this topic are as follows: • Support the adoption of improved marking technologies through cost-benefit studies of improved practices. • Focus attention on the migration of RFID technologies to buried utilities, although technologies are most likely to be commercially developed with private intellectual property. • Develop standard practices for RFID data sets. • Include locatable plastic pipe and RFID prototype applica- tions in the recommended DOT demonstration projects. Liability and Security Management Several key issues are always raised when common databases, data sharing, 3-D positional information for utilities, or all of these issues are discussed: • If a common database is used, who inputs the data, who verifies it, who pays for it, and who has access (commercial- secret protection and hacker or terrorist protection)? • If discrete databases are used, who sets the standards, who has access, and who controls security? • In either case, there is the issue of how to handle liability for erroneous information or how to protect against claims when data is misused. Similar problems affect military and other government data- bases with distributed updating and various levels of access security. What is needed is a realization that the current approach to utility recordkeeping leaves many undesirable problems and few paths for major improvement. Resistance to

65utility information-sharing is expected to be very strong based on realistic concerns about the use of the data. It will need to be shown that a utility company’s concerns can be properly addressed before such collaborations can effectively move forward. The recommended actions in regard to this topic are the following: • The demonstration projects mentioned elsewhere should include a demonstration of data sharing (with appropriate protections in place) so that problems can be identified and resolved. • Technology partners must demonstrate the capability to manage security, access control, and data-pedigree infor- mation. • Once these projects have been successfully demonstrated and evaluated, broader implementation approaches need to be addressed, including data standards and liability relief for best-faith information provision. Funding, Procedural, and Contractual Issues It was asserted earlier in this report that, given adequate time and budget, a team with the appropriate education and expe- rience could find most, if not all, of the utilities on a site— except perhaps for deep, unrecorded utilities. Naturally, improved technologies will speed and improve identification and will potentially lower costs. This means that it is also crit- ical to deploy and more effectively use the technologies that are already available. Several key issues were raised in chapters 3 and 4, and some of these issues are highlighted here. One issue is the tendency of project owners to gamble that utility problems will not arise. While this will save money on specific projects in the short term, it may eventually lead to large cost overruns if the information on which an owner relies is wrong. Guidance on typical costs and schedules for the relocation of various types of utilities would be helpful for use in preliminary project- planning estimates and in allocating adequate resources for early utility data collection. Also, guidance on what utility data is to be collected, when it is to be collected, and what accuracy is needed should be provided in the form of a scope of work or manual of practice. It would also be helpful if the funding and contractual framework required the right equipment to be brought to the site in accordance with the operational requirements related to detection rate, depth range, and reso- lution. Furthermore, the engineering and design consultants must bear some responsibility for the correctness of utility location information as well as for design. There is little infor- mation about liability issues, relevant case law, standards of care, and guidance to improve performance and avoid prob- lems. If design and construction contracts anticipate utility-related change orders in a manner similar to how uncertain geotechnical data is handled, then contractual disputes will be minimized when utility information is updated. In addition, flexible utility location and characterization funding is needed in the early stages of a transportation project. Fixing budgets at an average cost per mile for utility surveys and coordination does not allow for a response to complex or high-risk condi- tions in the early stages of a project. The goals of better utility location at the various stages of a project are as follows: • Planning: Select alignment to avoid problems and lower total costs. • Design: Avoid redesign, delays, and cost increases. • Construction: Avoid utility hits, injuries, change orders, delays, and cost increases. The recommended actions in regard to this topic are as follows: • Address funding, procedural, and contractual issues to improve the situation regarding the interaction of trans- portation projects and utility plants. There are many poten- tial avenues for such improvement, but it is recommended that a guidance document concerning the funding, proce- dural, and contractual issues be prepared and provided for transportation project designers, DOT staff, and manage- ment personnel. This should include information on typical costs and schedules for utility relocations and repairs and cost-risk scenarios, allowing some comparison of utility- location costs versus incurred risk later in the project. • Support the development and adoption of utility damage- prevention efforts. Many best practices are available through the Common Ground Alliance. • Support the development and adoption of technologies aimed at damage prevention when construction is under way. Specific promising technologies include the following: – See-ahead utility detection systems that work with excava- tion, drilling, or tunneling equipment. They do not address the planning and design issues but do avoid the signal pen- etration issues for GPR utility detection because the dis- tances being scanned are short. – Automatic checking of the GPS coordinates of a working excavator against previous one-call ticket locations. This addresses the issue of non-one-call compliance and pipe- line encroachment—both of which have been shown to cause utility damage and public safety issues. Demonstration Project Development Demonstration projects have frequently been mentioned as a step toward encouraging innovation and, more importantly, encouraging the adoption of innovation. One possible example of funding and managing demonstration projects related to the

66mapping of underground utilities within highway rights-of-way is the Off-System Bridge Rehabilitation Program (OSBR). This program is managed by the state DOT that oversees the design and construction of bridge replacements on highways that are not state or federal roads. This is a joint effort among FHWA, state DOT, and county officials. Funding for design and con- struction is 80% FHWA and 20% state. Counties have the responsibility of acquiring rights-of-way, relocating utilities, and providing traffic control devices, to name a few. Funding incentives from SHRP 2, matching funds from FHWA, and state and local matching funds could be used to develop specific demonstration projects. It is recommended that mapping and database management should be under state DOT jurisdiction. This would allow or mandate that under- ground utilities be managed within major highways that already fall under state DOT control. Also, state DOTs would ensure that the data or database is in a file format or computer program that is common, compatible, and easy for transporta- tion engineers to use. By requiring local matching funds, local urban municipal- ities might have the opportunity to participate in the program, as well to include their local streets. It would be in the best interest of urban municipalities to know where the utilities are actually located under their streets. Rural counties could choose not to map utilities on their more rural roadways, which are not as likely to undergo a major widening or improvement project. Education and Training Despite the extensive network of underground utilities and pipelines across the United States, very few formal education and training resources specifically address design, operation, and maintenance of these assets. Limited efforts have been made to introduce pipeline-related courses and utility asset management instruction into engineering curricula, but this introduction is difficult because of the numerous educational and training needs for each branch of engineering. Utility locating and characterization is, practically speaking, not addressed at all in the majority of engineering curricula in which transportation design project personnel are educated. The topic is most closely related to the study of geophysics in scientific or engineering curricula. Geophysicists are most likely to be involved in new locating and characterization equipment development. Use of general-purpose locating equipment is likely to fall to general construction personnel who have varying levels of training on how to use the equip- ment and on the physical phenomena affecting the output of the equipment. This situation is not conducive to the effective management, location, and characterization of underground utilities. On a positive note, the issue of site investigation and mapping ofburied assets is starting to make its way into texts dealing with buried utilities, such as in Read (29), which has a chapter titled “Site Investigation and Mapping of Buried Assets.” Potential actions in education and training related specifi- cally to the technology of utility locating and characterization include the following: • Educational materials could be prepared that provide an understanding of the physical principles behind technologies used in utility locating and characterization and that are aimed at formal engineering and construction curricula in universities. This could include short modules suitable for adoption in transportation-related classes or other sectors of engineering curricula. It could also include a more extensive module suitable as a stand-alone short course or for incor- poration in undergraduate or graduate courses covering infrastructure management, pipeline design, underground construction, and so forth. (See Table 6.1 for a curriculum proposed by Lew and Anspach (30).) • Educational materials could also be prepared for use by designers, policy makers, and other stakeholders that address the capabilities of existing and novel technologies, the importance of utility issues in transportation projects, and guidelines for best practices in terms of procedures to be followed to allow agencies to get the most out of the tech- nologies and SUE processes that they adopt. Proposed Project Alternatives The avenues of improvement described in previous sections were evaluated with respect to the expected duration and fund- ing constraints of SHRP 2, the desire for short- to mid-term results, and minimal duplication of activities under way by1. Utility system design and construction practices 2. Surface geophysical techniques for imaging utilities 3. Survey practices/engineering surveys/control surveys 4. CADD platforms/GIS and data management/mapping 5. Economic issues for utility relocations 6. Right-of-way issues/national accommodation policies 7. Utility damage prevention laws, construction site safety 8. Traffic control, management, scheduling 9. Contract law, indemnification/insurance/liability issues 10. Communication skills, existing standards/best practices 11. Utility condition assessment, repair vs. replacement economics 12. Highway design/structure design/hydraulic design Table 6.1. SUE-Related Educational Needs (30)

67other organizations. As a result, nine target research and devel- opment activities were identified (including related educa- tional components). As described in chapter 2, these nine alternatives were ranked by importance to SHRP 2 by a panel of 14 experts representing a range of participants in the trans- portation and utility sectors and including the key research team members. While there was significant variation in impor- tance assigned to specific topics, a fairly clear ranking of pre- ferred alternatives emerged from the group as a whole. The result of the ranking process is shown in Table 6.2 with a score reflecting the degree of consensus and the relativeimportance of the topic. The final scores are relative to each other and, thus, can best be interpreted by considering the groups of target activities with similar scores. Storage, retrieval, and use of utility data and the development of multisensor platforms were given the greatest importance, followed closely by the development of guidelines. It is inter- esting to note that the top three investment alternatives focus on legacy problems with respect to dealing with existing underground infrastructure conditions. The second-highest priorities are smart tagging, education and training, and location of deep utilities, which either plan for the future orRank (Score) Topic, Description, and Benefits 1. (0.17) 2. (0.16) 3. (0.14) 4. (0.12) 5. (0.10) 6. (0.10) 7. (0.08) 8. (0.07) 9. (0.06) Topic: Storage, Retrieval, and Utilization of Utility Data Description: The development of dedicated software and hardware that would take advantage of recent advances in GPS and GIS technologies and increase the quality and efficiency of storing, retrieving, and utilizing utility records. Benefits: Increasingly comprehensive and accurate utility records, allowing resources to be focused on finding the remaining utilities. Topic: Multisensor Platforms Description: The development of multisensor platforms that combine two or more existing technologies [e.g., ground- penetrating radar (GPR) and electromagnetic (EM) location or GPR and acoustic approaches]. Benefits: More reliable performance for utility locating across a variety of soil conditions. Topic: Development of Guidelines Description: The development of guidelines and other tools for the conduct of utility investigations for transportation projects. Benefits: Allows transportation designers/planners to get the most out of the SUE data they receive so as to maximize the benefit/cost to the agency. Topic: Smart Tagging Description: Advances in hardware and software that support smart tagging (e.g., ball markers, RFIDs) and documentation of utilities during initial installation and when exposed during excavations for various purposes. Benefits: Improved in-field identification of utility location, type, and characteristics. Topic: Initiation of Education and Training Description: Initiation of educational, training, and dissemination activities aimed at increasing the awareness of transportation engineers and other decision makers to the state of the art and cost-benefit implications of gathering better utility informa- tion early in the design process. Benefits: Improved allocation and more effective use of utility locating expenditures. Topic: Location of Deep Utilities Description: The development of locating technologies that target deep utilities that currently cannot be detected by surface- based approaches. These could include direct-path detection methods deployed from inside a utility or cross-bore tech- niques based on vacuum-excavated boreholes. Benefits: Improvement in detection of the most difficult utilities to find from the surface and reduced impact of unlocated or mislocated deep utilities on transportation projects. Topic: External Soil Void Detection Technologies Description: The development of new technologies or enhancement of existing technologies capable of locating and charac- terizing external soil voids from within a buried pipe or culvert. Benefits: Detection of future ground instability problems that can cause road settlement and sinkholes. Topic: Benchmarking of Current Technologies Description: The use of existing and/or purpose-constructed test facilities to systematically evaluate and document the capa- bilities and limitations of current utility locating equipment under controlled conditions of varying complexity. Benefits: Independent information on the capabilities of different types of detection equipment. Topic: Deformation Characterization Technologies Description: The development of new technologies or enhancement of existing technologies capable of characterizing the cross-sectional deformation of buried pipes and culverts over time. Benefits: More reliable performance for utility locating across a variety of soil conditions. Table 6.2. Ranked Priorities for SHRP 2 Funding Related to Utility Locating and Characterization Technologies

68address specific issues. The third-highest priorities include the detection of external voids, benchmarking of current technolo- gies, and deformation characterization technologies. This indi- cates that while utility-condition assessment is valuable, it is not the most urgent issue affecting transportation projects. The relatively low priority that was placed on the benchmarking of current technologies suggests that the existing body of knowl- edge that describes the key capabilities and limitations of major classes of utility locating techniques is considered adequate when compared against other urgent needs. References 1. Osman, H., and T. E. El-Diraby. Subsurface Utility Engineering in Ontario: Challenges & Opportunities. Report to the Ontario Sewer & Watermain Contractors Association. Centre for Information Sys- tems in Infrastructure & Construction, University of Toronto, Dept. of Civil Engineering, Oct. 2005, p. 71. 2. C. Paul Scott, TBE Inc., James H. Anspach, So-Deep, Inc., personal communications, p. 4. 3. Sinha, S. K., H. R. Thomas, M. C. Wang, and Y. J. Jung. Subsurface Utility Engineering Manual. FHWA-PA-2007-510401-08, Pennsyl- vania Transportation Institute, Penn State University, University Park, Pa., Aug. 2007, p. 136. 4. Nelson, R., and M. Daly. Creating a Major Emphasis on Damage Prevention. Proc., Damage Prevention Convention, Atlanta, Ga., Dec. 1998. 5. Doctor, R. H., N. A. Dunker, and N. M. Santee. Third-Party Dam- age Prevention Systems. GRI-95/0316, NICOR Technologies, Oct. 1995, p. 199. 6. Purdue University. Cost Savings on Highway Projects Utilizing Sub- surface Utility Engineering. Report prepared for U.S. Federal High- way Administration, No. DTFH61-96-00090, Dec. 1999, p. 174. 7. National Research Council. Seeing into the Earth: Noninvasive Char- acterization of the Shallow Subsurface for Environmental and Engineer- ing Applications. National Research Council, Washington, D.C., 2000, 148 pp. 8. Hereth, M., B. Selig, K. Leewis, and J. Zurcher. Compendium of Practices and Current and Emerging Technologies to Prevent Mechan- ical Damage to Natural Gas and Hazardous Liquids Transmission Pipelines. GRI 8747, March 2006, p. 119. 9. Common Ground Alliance. CGA Review of NTSB Recommenda- tion: Sponsor Independent Testing of Locator Equipment Performance under a Variety of Field Conditions. Develop Uniform Certification Criteria for Locator Equipment. P-97-16 and P-97-17, CGA, Feb. 2003, p. 49. 10. Common Ground Alliance. CGA Review of NTSB Recommenda- tion: Review State Requirements for Location Accuracy and Hand- Dig (Special Care) Tolerance Zones. P-97-18, P-97-17, CGA, Feb. 2003, p. 50. 11. Sterling, R. L. Utility Locating Technologies: Statement of Need (SON). Federal Laboratory Consortium Special Reports Series no. 9, FLC, June 1999, p. 19.12. Sterling, R. L. Utility Locating Technologies: A Summary of Responses to a Statement of Need. Federal Laboratory Consortium Special Reports Series no. 9, FLC, Feb. 2000, p. 53. 13. K. Kothari, personal communication, p. 15. 14. D. Jarnecke, personal communication, p. 15. 15. NASA to Provide Sharper Underground View of World Trade Center Area. NASA press release, NASA Jet Propulsion Laboratory (JPL), Aug. 2002. 16. Bakhtar, K. Demonstration of BakhtarRadar Buried Utility Detection and 3-Dimensional Imaging Capabilities. PowerPoint Presentation, 2006, 32 slides. 17. Underground Facility Pinpointing Demonstration: Bakhtar Asso- ciates, EarthRadar. Attachment 5 to a GTI report provided by Bakhtar Associates, Newport Beach Calif., 2006. 18. Manacorda, G., H. Scott, M. Rameil, R. Courseille, M. Farrimond, and D. Pinchbeck. The ORFEUS Project: A Step Change in Ground Penetrating Radar Technology to Locate Buried Utilities. Proc., Pre- sented at ISTT NoDig 2007, Rome, Sept. 2007. 19. Center for International Disaster Information. Church World Service: Emergency Response Program. Revised Landmine Appeal for $150,000. Humanitarian Activities Report Landmines—CWS, CIDI, Feb. 2001, 2006, p. 3. 20. Ishikawa, J., M. Kiyota, and K. Furuta. Test and Evaluation of Japa- nese GPR-based AP Mine Detection Systems Mounted on Robotic Vehicles. Journal of Mine Action, Issue 10.1, Aug. 2006, p. 16. 21. Welch, W.M. In Age of Terror, U.S. Fears Tunnels Pose Bigger Threat. USA Today, March 1, 2006, p. 2. 22. U.S. Army. Army Advanced Concept Workshop on Shallow Tunnel Detection. University of Mississippi and U.S. Army Research Office, National Center for Physical Acoustics, Research Triangle Park, N.C., 2006. http://pangea.stanford.edu/research/enviro/Tunnel%20Con ference%20White %20Paper.pdf. 23. Dizzard, W. P., III. DHS Seeks Tunnel Vision. Government Computer News, Feb. 2007. 24. Lanka, M., A. Butler, and R. Sterling. Use of Approximate Reasoning Techniques for Locating Underground Utilities. A Supplement to Tunneling and Underground Space Technology, Vol.16, No.1, 2001, pp. 13–31. 25. Crice, D. MASW, The Wave of the Future. J. of Environmental & Engineering Geophysics, Vol. 10, June 2005, pp. 77–79. 26. Ellis, R., M. Venner, C. Paulsen, J. Anspach, G. Adams, and K. Vandenbergh. SHRP 2 Report S2-R15-RW: Integrating the Prior- ities of Transportation Agencies and Utility Companies. TRB, Wash- ington, D.C., 2009. 27. Best Method Available. World of Training, One-Call Edition, May 2006, p. 39. http://www.underspace.com/WOT/index.php. 28. American Society of Civil Engineers. Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data. ASCE Standard No. CI/ASCE 38-02, ASCE, Reston, Va., 2002, 20 pp. 29. Read, G.F. Sewers: Replacement and New Construction. Elsevier, 2004, p. 576. 30. Lew, J. J., and J. Anspach. Developing Curricula for Subsurface Utility Engineering (SUE). Proc., CIB W89 International Conference on Building Education and Research BEAR 2003, Lowry, Salford, United Kingdom, April 2003, 13 slides.