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

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3   Roadway and utility infrastructure frequently share public right-of-way (ROW) to accommo- date their facilities. This scenario is often the result of a state department of transportation (DOT) acquiring ROW for their roadway alignment and the utility facilities requesting permitted access to install their infrastructure within the same corridor. The FHWA, among others, has recog- nized this practice to be in the public interest when the utility occupying the public road ROW can do so without adversely affecting safety, without impairing the highway or its aesthetics, and without violating federal, state, or local laws and regulations (FHWA 2018c). This approach creates efficiency for the taxpayer and ratepayer, who are one and the same. However, decades of these accommodations have resulted in utility-related issues being one of the leading causes of delay for transportation projects. In fact, a recent FHWA Program Review of state DOT utility-coordination practices found utility issues to be among the top-three causes of delay in delivering transporta- tion projects (FHWA 2018a). The report goes on to specifically identify categories of common util- ity issues, including lack of accurate utility-location information, among others (FHWA 2018a). Subsurface utility engineering (SUE) is an approach state DOTs have implemented to locate utilities and assist their project-development and utility-coordination teams in resolving some of these issues. 1.1 Background SUE has been standardized by the ASCE, Construction Institute Standard 38-02, “Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data.” This standard, while currently being revised, has been instrumental in ensuring more uniform practice of SUE since its development in the 1980s. SUE, as defined by the ASCE, is an engineering practice involving “the management of risks associated with potential utility impacts through mapping utility locations at appropriate quality levels, utility coordination, utility relocation design and coordination, utility condition assessment, communication of utility data to concerned parties, utility relocation cost estimates, implementation of utility accommodation policies, and util- ity design.” The process involves multiple stages, including scoping, designating, locating, data management, and conflict analysis. In SUE, traditional processes, such as records research and site surveys, are coupled with new technological methods, such as geophysical methods and nondestructive vacuum excavation, to provide an investigation that leads to locations of judged “quality levels” for each depicted utility segment (FHWA 2017). These quality levels form the basis of SUE practices as they describe the relative positional and attribute certainty of a utility or portion thereof through categorizing the results from which its investigation judged reliable. A project team can determine what quality level is necessary to adequately design and construct their project and seek more certain levels at specific locations as needed, which typically entails additional cost. C H A P T E R   1 Introduction

4 Implementation of Subsurface Utility Engineering for Highway Design and Construction There are four distinct quality levels that vary from Quality Level A (QLA), the highest level of the definition, to Quality Level D (QLD), the lowest level of the definition. Each quality level includes various combinations of existing-records research, site surveys, geophysical technology, and air- vacuum technology. The following describes the four quality levels in more detail (FHWA 2018b). • “SUE Quality Level D (QLD): contains data that is primarily obtained from existing utility records or verbal recollections, both typically considered unreliable sources. Combined, these sources may provide an overall ‘feel’ for the congestion of utilities, but are often highly limited in terms of comprehensiveness and accuracy. Although, this is the most basic level of infor- mation for utility locations. QLD is useful primarily for project planning and route selection activities” (FHWA 2018b). • “SUE Quality Level C (QLC): is the most commonly used level of information. It involves surveying visible utility facilities (e.g., manholes, valve boxes, etc.) and correlating this infor- mation with existing utility records (QLD information). When using this information, it is not unusual to find that many underground utilities have been either omitted or erroneously plotted. Its usefulness, therefore, is primarily on rural projects where utilities are not preva- lent, or are not too expensive to repair or relocate” (FHWA 2018b). • “SUE Quality Level B (QLB): involves the application of appropriate surface geophysical methods to determine the existence and horizontal position of virtually all utilities within the project limits. This activity is called ‘designating.’ The information obtained in this manner is surveyed to a project control (known location benchmark). It addresses problems caused by inaccurate utility records, abandoned or unrecorded facilities, and lost references. The proper selection and application of surface geophysical techniques for achieving QLB data is critical. Information provided by QLB can enable the accomplishment of preliminary engineering goals. Using QLB information, decisions regarding location of storm drainage systems, footers, foundations and other design features can be made to successfully avoid conflicts with existing utilities. Slight adjustments in design can produce substantial cost savings by eliminating utility relocations” (FHWA 2018b). • “SUE Quality Level A (QLA): also known as ‘locating,’ is the highest level of accuracy certainty presently available and involves the full use of the subsurface utility engineering services. It provides information for the precise plan and profile mapping of underground utilities through the nondestructive exposure of underground utilities, and provides the type, size, condition, material and other characteristics of underground features” (FHWA 2018b). QLD has the least amount of financial investment but simultaneously has the highest degree of risk for DOTs because QLD provides the least amount of information and has limitations in accuracy, certainty, and comprehensiveness. This risk is primarily realized in the form of change orders, utility damage, and other unexpected problems (Lew 1999). As the quality level improves from QLD to QLA, the initial cost rises, but the potential for unexpected costs decreases. The programmatic use of SUE, often referred to as a SUE program, is the formalized plan by a state DOT to implement SUE based on project criteria (or for all projects). Then, on a project basis, teams can align quality-level needs with appropriate stages of project development and/or delivery. SUE programs lead to more successful underground projects and reduced subsurface-utility damages (Lew 1999). Additionally, a risk-based SUE program is one of the recommendations made by the FHWA Program Review (FHWA 2018a). While the previous definitions present a standardization of SUE quality levels, studies have noted variations in the implementation of these quality levels by state DOTs. In fact, as noted within this synthesis and other research, DOTs vary with regard to when SUE is initiated, how various quality levels are implemented, and how the data collected is communicated within plans and contract documents. This presents an opportunity for more standard implemen- tation of SUE by state DOTs. This is further highlighted in NCHRP Synthesis 506: Effective

Introduction 5   Utility Coordination: Application of Research and Current Practices, where 61% of DOT respon- dents noted that “improved understanding of SUE” was the top utility-coordination-research need (Sturgill et al. 2017). 1.2 Synthesis Objective The objective of this synthesis was to document current DOT use and practices related to SUE. Specifically, this synthesis examined how DOTs use SUE and when SUE is implemented during the project-design and delivery processes. The study further investigated how SUE has been defined by DOTs, what aspects of SUE have been adopted or adapted, and how these approaches impact stakeholders and the progress of highway projects. The scope of the synthesis is confined to the implementation of SUE in DOT highway-design and construction projects but may include varying project types, delivery methods, and implementation methods. This synthesis of SUE practice and state DOT implementation will assist those considering more integrated use of SUE and aid those developing a SUE program. Information gathered to support this objective includes: • The extent of DOT use of SUE (i.e., how many agencies have a SUE program); • How the decision to use SUE is made and at what point in the project-delivery process the decision is made; • DOT policies and procedures that guide SUE deployment; • How SUE deliverables are obtained (e.g., in house, SUE contract service, utility owner, highway-construction contractor); • At what point in the project-delivery process is SUE deployed (e.g., concept development, preliminary design, final design); • Type of projects that typically use SUE (e.g., project excavation, foundations, urban versus rural, major versus minor roadway projects, project funding threshold); • Use of SUE for various project-delivery methods; • Quality assurance/quality control (QA/QC) procedures and processes for SUE deliverables; • DOT-documented measurement of cost savings or risk reduction; • How DOTs use and store SUE data after the project; • Whether SUE is performed after utility relocation; • An overview of SUE implementation approaches at DOTs; and • Challenges understood in the implementation of SUE at DOTs. 1.3 Study Approach To achieve the synthesis objective, the study team conducted an extensive literature review, sent a survey to state DOT representatives, and performed in-depth case example interviews. The literature review provided an initial understanding of the current state of research and practice, and, along with discussions with state DOTs, the synthesis panel and other SUE experts assisted in the development of the survey questionnaire. The survey was distributed to the utility-related membership of the AASHTO Committee on Right of Way, Utilities and Outdoor Advertising Control (CRUO). A total of 41 state DOTs participated in the survey among the 51 requests sent (50 states and Washington, DC), providing an 80% response rate. Following the survey, subsequent case example interviews were conducted to gather further information on the use of SUE. Cases were identified based on a combination of the state’s survey responses regarding their use of SUE, and six states participated in these interviews. They were Colorado, Georgia, Maryland, Minnesota, Pennsylvania, and Texas.

6 Implementation of Subsurface Utility Engineering for Highway Design and Construction 1.4 Report Organization This report is organized according to the study approach just described. Following this intro- duction, Chapter 2, Literature Review, presents the findings from the literature and research investigated. Chapter 3, State of the Practice, presents findings of the survey distributed to the state DOTs. The survey questionnaire is provided in Appendix A with the detailed results provided in Appendix B. The details of the individual case example interviews are outlined in Chapter 4, with the questions guiding the interviews found in Appendix C. Chapter 5, Summary of Findings, presents the cumulative findings of the synthesis and needs for future research. A summary of the synthesis is provided at the beginning of this report.