Use of Automated Machine Guidance within the Transportation Industry (2018)

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NCHRP Project 10-77 1 CHAPTER 1: INTRODUCTION Using automated machine guidance (AMG) technology in transportation construction projects allows state agencies and contractors to deliver projects better, safer, faster, and more cost-effectively. This research project, NCHRP 10-77, Use of Automated Machine Guidance (AMG) within the Transportation Industry, was initiated to advance the integration and implementation of AMG. This report summarizes the findings and outcomes of this project. PROBLEM STATEMENT AMG technologies are continuing to be adopted by contractors because it improves construction efficiency and quality. Agencies are improving electronic design processes that support AMG construction and deliver higher quality products to the public. Equipment providers are rapidly advancing software tools and machines systems to increase automation in the design and construction process. Motivation to more widely integrate and adopt AMG processes therefore exists. However, the framework for adoption of AMG into the complex framework of design to construction has not been comprehensively documented in one source and it would be desirable to more fully develop some details of the framework. Technical, equipment, software, data exchange, liability/legal, training, and other barriers limits progress with AMG implementation into construction projects. This study was designed to understand and develop guidelines to improve AMG implementation. Figure 1-1 shows what might be considered as common design rendering and equipment on modern construction projects now, yet the workflow processes to fully benefit from AMG processes is complex. Also, the spectrum of AMG technologies is now wider than ever with advancements in software tools, machine technologies, position equipment and sensors. In the future, AMG has the potential to be integrated well beyond basic earthwork operations. Guidance is needed on how best to advance and benefit from these technologies. (a) (b) Figure 1-1. AMG Applications involving (a) Three-Dimensional (3D) Design and (b) Application of AMG in Earthwork Grading (images curtesy of Iowa DOT and Caterpillar) RESEARCH OBJECTIVES AND SCOPE The project focused on three outcomes: 1. Guide specifications for AMG technology 2. Guidance on the use of such technology in construction projects

NCHRP Project 10-77 2 3. Strategies for implementing AMG technology into construction projects Key obstacles that need to be addressed: • Development and transfer of three-dimensional (3D) electronic files • General lack of knowledge of the subject matter • Overcoming legal barriers • Understanding the impact of AMG technology in terms of both benefits and liabilities RESEARCH APPROACH The project team believed it would serve the project well to establish an expert contact group early in the project, so they could seek its advice throughout the project. The expert contact group included a full range of experts such as: • Earthwork and paving contractors • Equipment manufacturers and dealers • Software developers • State agency representatives • Academics Due to the broad and complex nature of the AMG technologies and process, the project research team convened the expert contact group for an intense workshop during the second month of the study. One objective of the workshop was to accomplish an initial review of survey questions planned for distribution to garner national and international feedback on implementation of AMG. The other main objective of the workshop was to develop a list of capabilities that must exist and obstacles that must be overcome to facilitate seamless electronic data transfer—from initial surveying, to the development of digital terrain models (DTMs), through design and construction, to final inspection and verification. The workshop commenced with a presentation about the objectives of the research project and the workshop, then participants were assigned to one of the following breakout groups. 1. Legal impacts 2. Development of 3D files 3. Accuracy best practices and inputs/outputs 4. Bid item quantity 5. Review of the proposed survey objectives and questions 6. Training information requests Participants in each group brainstormed lists of challenges and opportunities in their areas. Participants reviewed the breakout session lists and identified other topics, then combined and organized the topics into a list. The participants voted on the priority order of the topics, and a list of the top 10 challenges/opportunities was developed. Discussions in subsequent sessions provided details and synthesized contexts for the top 10 list items (see Table 1-1). Participants also gave feedback about the survey. The complete Workshop Report is included as Appendix A.

NCHRP Project 10-77 3 Table 1-1. Synthesized and Ranked Priorities – General Session from AMG Stakeholder Workshop Rank Topic and Synthesis 1 Data: There is a need to improve data management and electronic data exchange formats, such as xml and LandXML. These data exchange formats are not sufficiently robust to be appropriate for wide adoption. Improvement of data exchange procedures between design and construction entities is an opportunity for improvement. 2* Training and Education: Training and education is needed for all types of participants, including agency and contractor professional engineers, designers, and field personnel. 2* Standardization: In general, it would be desirable to modernize specifications. Non-standardized AMG specs among states and the lack of standards for software and hardware are hindering the implementation of AMG. Areas for improvement include better definition of project survey control (set and maintain) and development of standard data feedback loops as bases of payment (quantities) for accurate pay estimates. 4 Quality/Improvements: AMG provides opportunities to provide grade checks that cover essentially 100% of the surface. In addition, it is possible to incorporate utilities in models, in their as-built locations, by referencing them before they are covered. Effective model verification will result in better QA/QC. Procedure error and clash detection will result in a better final product. Other possible benefits include increased productivity and improved industry perception and image, due to the use of higher technology solutions. However, to obtain these benefits, it will be necessary to carefully identify the proper technology for each specific implementation. 5 3D Model: By conducting initial discussions with stakeholders early in the project using 3D designs, it is easier to obtain understanding and agreement. Performing virtual construction, before actually building, results in improved plans and fewer mistakes. Errors become readily apparent during a 3D video fly-through. Designers can visualize subgrades and find utility conflicts. An opportunity for this group is to coordinate with the Associated General Contractors Build Information Modeling (AGC/BIM) group that is working on horizontal construction. Software developers have already started developing a horizontal construction version of BIM. 6 Benchmark Case Studies: There is an opportunity to develop a set of case studies that demonstrate the use of AMG through the design and construction process. Contracting authorities and others may be more willing to adopt and encourage the use of AMG after they have read the case studies. 7 Legal Challenges: Requiring licensed surveyors or engineers to perform the conversion of 3D models into machine control files could delay the adoption of AMG technology. The question exists about who is responsible for the design, if plans are stamped twice by two different people: the original designer and/or the person who was responsible for the conversion. Another question is, “What becomes of the legal record of the design?” Can a 3D model be part of the contract documents? Is it possible to make electronic plans the legal document that represent the design? 8 Safety: Considerable increases in safety are possible, because fewer people are working on the ground around the equipment as they set and reference stakes. 9 Real-Time Network Support for Virtual Real-Time Network to Work for AMG: An opportunity for improvement would be to enhance virtual real-time networks so that they can replace base stations for use with AMG applications. Currently, signal latency issues compromise the accuracy to such an application. 10 AMG Applications for Subgrades/Paving/Overlays: There are some unique challenges and unique opportunities for AMG applications on subgrades, paving, and overlays. * Equal number of votes Building on the knowledge gained from the early workshop outcomes, the research team deployed surveys that targeted private industry and transportation agencies. More than 5,000 survey respondents were solicited. The results of the survey findings were used to pinpoint industry needs and shortcomings within AMG processes. Legal aspects, specifications, training, accuracy, impacts, and other aspects were studied. The research team also constructed a searchable electronic library of information

NCHRP Project 10-77 4 related to AMG and supporting technologies. The project’s bibliography contains more than 370 documents organized into categories and sub-categories. Because educational and training programs were identified as an especially critical need for stakeholders to maintain productivity and accuracy on AMG projects, this topic was studied in detail by using survey outcomes and collecting information from equipment providers, contractors, and academic intuitions on education and training offerings. An assessment of the findings was used to shows that education and training are provided by various sources; however, no one source provides all the preparation necessary for full AMG implementation. The research team also worked on understanding and developing best practices for the creation of the electronic 3D models that are central to the success of AMG. To develop best practices, the research team approached this topic from the perspectives of designers, contractors, developers, and those who synthetize the information. It is common knowledge that earthwork pay items are historically objects of great dispute between agencies and contractors, so the research team focused on studying AMG accuracy and its application to pay quantities. Several technologies were studied in terms of position accuracy. Using the expert contact group, the research team developed a detailed matrix that lists sources and frequencies of errors in the AMG process, and, equally importantly, associated error detection and mitigation strategies. An earth-berm test bed was set up to capture position data to specifically quantify errors introduced from different terrain modeling methods. Further, field experiments were conducted on three project sites to evaluate Global Navigation Satellite System (GNSS) technologies mounted on roller compactors in terms of position reproducibility and repeatability. The experiments demonstrated the use of a proposed statistical analysis method to quantify machine-level measurement errors for different ground conditions, machines, and operational parameters. Because AMG covers a wide range of equipment and applications, a matrix of similar proposed field studies was developed. The technology behind AMG can exist in “information silos” within different user functional areas, so the research team studied and developed detailed workflow process diagrams. The workflow diagrams were based on survey information, contractor and agency interviews, bibliographic content, and studies of product information. Although the workflows were developed during the later stages of the research effort, they are presented at the beginning of this report to establish a baseline for the reader. Near the end of this report, the results of a specification review and synthesis are presented. The research team relied upon the information obtained from the literature and specification reviews, the surveys, and the expert contact group workshop. Results were used to create guide specification tool. Finally, a discussion of the future of AMG was developed by identifying the various workflow process and technologies used in AMG and overall needs for advancement discussed in this report. REPORT ORGANIZATION This rest of this report is organized into eleven chapters. Chapter 2 describes the basic processes of AMG in terms of the surveying process and the overall AMG design to site-level construction workflow. These narratives and flow diagrams provide a condensed explanation of the full AMG process. Chapter 3 describes the literature review and bibliographic library of information sources related to AMG and establishes an updated AMG lexicon. The project’s bibliography contains more than 370 documents. Chapter 4 describes the results of a detailed survey that garnered information from key AMG stakeholders worldwide. Chapter 5 presents the findings of a study of legal matters that may hamper the implementation of AMG processes, either by state transportation agencies or contractors, including electronic file use disclaimers, organized labor issues, and state statutes. Results were categorized into two areas (1) owner/agency reluctance to share electronic data design (EDD) with contractors and (2) definitions of functional roles with regard to 3D project delivery.

NCHRP Project 10-77 5 Chapter 6 lists and describes various AMG training programs and resources. Several on-line sources are referenced including university level and manufacturer level training. No one source provides all the training necessary for AMG. Chapter 7 describes best practices for the development of design models and emphasizes that good modeling demands communication, training, teamwork, and patience. Chapter 8 describes the impact of AMG on earthwork quantity estimates, which historically has been a source of great dispute between agencies and contractors. Information suggests that AMG will likely result in less confusion and more accuracy than traditional methods of earthwork payment. Chapter 9 focuses on numerous factors that influence the accuracy of AMG processes. Chapter 10 summarizes national specifications used for different AMG phases and provides a guide specification tool with basic language that represents the state-of-practice. Chapter 11 discusses a range of topics with a focus on exciting future possibilities for AMG application in transportation construction. Chapter 12 summarizes key outcomes from this study and describes future development and research opportunities. Several supporting reports and documents are included as appendices. A list of abbreviations, acronyms, initialisms, and symbols is provided following the references list at the end of the report. Four appendices (A through D), not published herein but available on the Transportation Research Board (TRB) website by searching for NCHRP Web-Only Document 250 (NCHRP Project 10-77), provide further elaboration on the research.