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

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NCHRP Project 10-77 140 CHAPTER 12: SUMMARY AND CONCLUSIONS Products developed from this research, including the guidelines and guide specifications can be implemented immediately. State DOTs will primarily implement these products improved AMG workflow processes and through letting of projects with AMG specifications. In the short term, state DOTs could implement AMG specifications on a limited basis as “special provisions” to existing and upcoming demonstration projects. Field demonstrations and on-site seminars on AMG technology and guide specifications delivered by the research team will further facilitate technology transfer/training and speed up the implementation process. As with any new specifications, for effective implementation, state DOTs, designers, and contractor agencies (e.g., trade associations such as Associated of General Contractors of America and its local chapters) will have to buy into and champion the AMG specifications. Ultimately, the success of AMG implementation can be evaluated by observing the number of states and projects that use AMG specifications. From a much broader perspective, and consistent with the research objectives, we believe that the collaborative methodology outlined in this research approach, making use of strategic stakeholder meetings and expert contacts, provides the best means of developing consensus and having sufficient impact on current practice to greatly expand the use of AMG technologies for transportation construction projects. The results of this research effort will be directly applicable in practice in the following ways: • State DOTs and contractors will be able to utilize the findings from this study immediately as guidance for making informed decisions about how AMG technologies and guide specifications can be used to improve earthwork construction operations. Because we are involving stakeholders in the development of AMG guide specifications, we believe that the developed specifications will be flexible and could be adopted by any state. • The findings from the study also provide state DOTs with valuable information regarding digital terrain modeling, electronic 3D design model development and enhancements for use in construction operations including AMG. In addition, these findings can be implemented immediately to develop guidelines for earthwork construction QA/QC. • The recommendations for AMG guide specification will provide consistency among the various manufacturer technologies, thus eliminating bias towards a specific technology and enabling the users to select from the wide range of manufacturers. Organized by subject heading the following points summary additional key findings from this research. AMG WORKSHOP • The AMG Stakeholder Workshop contributed directly to the needed outcomes of this study. The objective of the meetings was to develop a list of capabilities that must exist and obstacles that must be overcome to facilitate seamless electronic data transfer from the initial surveying to the development of DTMs through design and construction to final inspection and verification. • The outcomes of this workshop covered topics of (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, and (6) training information requests are presented herein. Based on a complete review of the comments, a top 10 list of challenges/opportunities was developed and is presented in the full report in Appendix A.

NCHRP Project 10-77 141 AMG WORKFLOW PROCESSES • A set of simplified workflow diagrams and narratives was presented to reflect the spectrum of processes and technologies that are organized according to these topics: - Surveying preparation workflow processes, - Roadway design workflow processes, - Contractor data preparation workflow processes, and - Overall integrated AMG workflow processes. • The accompanying narrative attempts to concisely describe the processes involved with the workflow steps first to establish a baseline for the remainder of the report, and, second, to appreciate that AMG is best positioned to succeed when survey, design, and construction processes are coordinated. Understanding these AMG workflow processes is also important for developing effective guide specifications for implementing AMG where critical roles and responsibilities can be defined. INFORMATION REVIEW • The research team constructed a searchable electronic library of information related to AMG and supporting technologies. The project’s bibliography currently contains more than 370 documents that range from peer-reviewed academic papers to specifications to transportation agency directives to manufacturer specific videos and others. The use of AMG technology is relatively new, and our study confirmed that the AMG literature base is not as mature as that of more-established technologies and procedures. As such, academic papers accounted for only 28% of the information sources in the AMP project bibliography. Documents collected by the team range in date from 2000 to 2014. • Even though information on AMG does not appear to have a large base of formally published papers, significant information was garnered through AMG-specific and -related websites and from slides from presentations at meetings held by transportation agencies, software and hardware vendors, and contractors. A detailed annotated bibliography and list of AMG specifications was generated from the information and literature review. In addition, a lexicon of terms used in AMG was developed and is reported in this chapter and is used through the remainder of this report. • One of the key outcomes from the information and literature review was that there is very limited independently studied information that quantifies AMG machine-level performance or site-level construction efficiency gains for AMG projects. These areas require more research to fully understand the benefits of using AMG and related technologies in construction processes. • The AMG information and literature that the team collected were initially organized in an electronic EndNote® database as a searchable and shareable annotated bibliographic record for the research team. As a result, the most important outcome of this portion of the project may be the ability to widely share this bibliography. • One outcome of the information review was a lexicon of AMG related terms (more than 30 terms) that can serve the basis for AMG terminology. SURVEY OUTCOMES • The project research team developed a detailed plan and conducted (upon NCHRP approval) a worldwide survey to determine what types of software and equipment are currently being

NCHRP Project 10-77 142 used to implement AMG processes. The survey involved these stakeholders: State transportation agencies, Software vendors, Equipment vendors, and Contractors • The survey covered these topics: Current drafting and design software capabilities, Types of electronic files that are submitted to contractors (such as .dgn, .dwg, .dtm, .tin, and LandXML files), When these files are made available to the contractors (such as pre-bid or post-award), Equipment capabilities and reliability, Perceived benefits and liabilities of AMG processes • Based on lessons learned from four information surveys, the research team conducted the work required for the survey using an Internet browser-based software application. A complete summarization of the survey results can be found in Appendix D. • A total of 504 people responded in whole or in part to the eight targeted surveys developed in this phase of the research. From these surveys information was garnered from a sample of all major AMG stakeholder groups, helping to define the current state of the industry. The project team developed separate survey questions for the various stakeholder groups, based on internal collaboration and the literature collected to date. • Survey outcomes are presented in the report. The analysis results are primarily descriptive statistics and provide new insights into the development of this newly emerged technology. LEGAL BARRIERS • The use of AMG technology in construction contracting has created changes in business work processes and contract delivery processes, affecting all the contract stakeholders. Some legal mechanism is needed to bridge the implied design warranty concerns (Spearin doctrine) and the ability to include EED as part of the contract documents. Currently, liability waivers and clauses are performing this function, in part, but it is yet to be tested in the courts, according to our research. • The work process changes, resulting in functional role changes, have proceeded faster than the regulatory and legal systems have accommodated. A standard definition of professional roles is needed across all the state license boards, which would help to define the “responsible charge” of the various professional stakeholders. Perhaps after this project, NCHRP could make recommendations to the NCEES for their Model Law document (NCEES, 2009), which is intended to “be used as a reference work in the preparation of amendments to existing legislation or in the preparation of new proposed laws. The intent of NCEES in preparing this document is to present to the jurisdictions a sound and realistic guide that will provide greater uniformity of qualifications for licensure, to raise these qualifications to a higher level of accomplishment, and to simplify the interstate licensure of engineers and surveyors.” • Defining professional roles will also require a standardized definition of EED, including what it is not to be used for. The Proposal for Use of EED in Construction created in 2008 by a joint AGC/DOT subcommittee does not address professional roles or duties, nor does it address contractual context. From the AGC document, EED is defined as, “In the civil segment of the construction industry, a three-dimensional representation (surface model) of what is to be constructed. Includes all types of capital project related engineering data which is used for defining, developing, designing, documenting, spatially locating, constructing, and historical recording.” • The good news, according to our project surveys, is that despite the legal hurdles, those with AMG experience perceive that it improves the spirit of cooperation between the contract stakeholders, through improved constructability communications. The project surveys have also indicated that the perception of liability regarding the exchange of EED is quite low.

NCHRP Project 10-77 143 AMG TRAINING OPPORTUNITIES • Good training programs will be necessary for stakeholders to maintain productivity and accuracy on AMG projects. An especially critical need exists for training on 3D modeling and project control points. • Training is provided by several various sources; however, no one source provides all the training necessary for AMG implementation. A considerable number of self-paced online opportunities are available, especially for learning about software. Meanwhile, hands-on, instructor-led opportunities predominate for equipment operation and using positioning hardware. Educational institutions are beginning to include AMG in their curriculums; however, educational goals are more general and focused on awareness and training is focused on execution. Therefore, AMG stakeholders must continue to train personnel to provide a solid foundation to existing and new members on their AMG teams. DEVELOPMENT OF DESIGN MODELS – BEST PRACTICES • Success in 3D site modeling is central to the success of AMG. Changing from 2D to 3D modeling comes with many important challenges in a variety of aspects, including training, workflow alteration, and clarifications or adjustments in professional practice. Two years of training and staged implementation may be required to completely switch from 2D to 3D design (Hixson, 2010; Vonderohe et al., 2010). A design team would have to complete three 3D projects before it reaches the returns of its accustomed level of productivity (using 2D methods)—and productivity would never exceed that of 2D modeling (Hixson, 2010). However, the product provided by the design team would be vastly improved (Hixson, 2010). • Changing from 2D to 3D modeling comes with important benefits, including better communication and error checking with internal and external stakeholders, less effort re- entering data from one phase of design and construction to the next, greater efficiency in construction, and site efficiency benefits, such as allowing the contractor to use the 3D model for cost estimating, development of means and methods, and for productivity tracking. Other incidental benefits include using the 3D model framework for as-built, QA and QC records, and after the project is completed, using it for maintenance and operational information storage, such as locations and dates of maintenance activities and crash-incident analysis. • Accuracy considerations are important in providing survey data and for developing the model. Compared to traditional methods, AMG will require more accuracy in more places because construction workers will not be able to fit construction by eye between locations where stakes exist. Compared to traditional methods of construction, AMG will require a greater density of preconstruction survey data collection and greater densities for pattern line locations during modeling. The need for accuracy must be balanced with requirements for data storage and manipulation capabilities in the modeling and construction processes. • Decisions regarding how data is transferred from one part of the AMG process to another are important. Having all stakeholders cooperatively build and modify the 3D model would provide a seamless method of data transfer. However, such a practice raises important questions regarding design responsibility and the division between activities that must be performed under the supervision of a licensed individual and those that can be performed without such supervision. For example, if more than one licensed individual supervises the modeling effort, communication will be required to clarify which person has responsibility in each specific area.

NCHRP Project 10-77 144 • For a contractor, the most important layers of a 3D model are the existing and proposed surfaces and line work for the proposed facility. Considerable contractor effort can be saved by giving them access to the 3D models developed by designers. However, legal and professional issues often restrict contractors from gaining such access. Contractors often detail areas that are hard to model. Changes that occur to the model after construction begins can be a challenge to incorporate into the construction version of the 3D model. • A predominant format for data transfer has not emerged. LandXML accounts for less than 10% of the file data transfer format at each phase of the 3D model lifecycle, except for during contract document creation, where it is at 12%. IMPACT OF AMG ON EARTHWORK QUANTITIES • Proper use of digital information for AMG will likely result in less confusion and more accuracy than traditional methods of earthwork pay item quantification and payment. Earthwork pay quantification from AMG must include mechanisms that all parties to the contract (both the agency-owner and the contractor) can trust. • Many software applications now have the capability to easily compute quantities using the surface-surface method. The accuracy of the generated DTM plays a significant role in the estimated earthwork quantities. Another key factor that contributes to the overall quantity estimation is the soil shrink-swell factors. • Model enhancement might be necessary during the development process for certain aspects, such as providing offsets between pavements and subgrades, delineating areas where equipment operation is excluded, and correcting inconsistencies that are not problematic for design models but are for AMG. • Most of the equipment vendors indicated potential productivity gain of about 40% and potential cost savings of about 25 to 40% using AMG. Contractors indicated potential productivity gain of about 10 to 25% and potential cost savings of about 10 to 25% using AMG. The results from detailed case studies described in the literature and survey responses indicate that the productivity gain and cost savings using AMG on earthwork projects can vary significantly (with productivity gains in the range of 5% to 270% and cost savings in the range of 10% to 70%). This variation is most likely because of various contributing factors, such as project conditions, materials, application, equipment used, position measurement technologies used, and operator experience. • It is extremely important that existing surfaces are portrayed as accurately as possible, so the model can be passed ahead to the design, estimation, bidding, and construction phases of the project with high fidelity. A proper understanding of the factors that influence the accuracy of the DTM is important to understand and must be addressed during the model development phase. • Survey results, reported in Chapter 3, indicated that a majority (> 70%) of contractors, software/hardware vendors, and agencies who responded believe that the number of elevation data points used in creating the DTM is a key factor in the accuracy of the DTM. ACCURACY OF AMG PROCESS • AMG component accuracies is an issue that affects various stages of the process including: Initial data collection for developing existing surface terrains; development of DTM and EED, AMG processes, procedures, and end-user competencies, QA/QC reported practices, heavy and fine grading equipment operations, and paving equipment operations.

NCHRP Project 10-77 145 • Sources of errors contributing to the overall AMG accuracy were identified as an outcome from the AMG Workshop and were related to frequency of error, means for detection, and mitigation strategies to overcome the error. Survey outcomes from contractors, vendors, and agency personnel on factors contributing to the overall accuracy of AMG are cross- referenced to the findings from the workshop results. It does not appear that the effect of construction process and human errors has ever been thoroughly studied or quantified. Most contractors, vendors, and agency personnel who responded to the survey questions reported that these variables play a key role in the overall accuracy of the AMG process. • A frequent problem reported with GPS-based technologies is limited availability of satellites (and, consequently, poor signal attenuation) when operating close to structures, trees, or underground environments. • The overall accuracy of the AMG process includes these construction process parameters: speed of operation, material type and support conditions (uniformity), and terrain. These parameters have not been thoroughly studied or documented in the technical literature and they are application-specific or machine-specific. An experimental plan to help quantify the influence of these factors on the overall accuracy of the AMG process is proposed for Phase II. The level of impact for each of these factors differs with the application type. • A detailed evaluation approach was presented that can be used to quantify of the several factors (machine related, technology related, and human related), which contribute to the overall accuracy of the AMG process. GUIDE SPECIFICATIONS AND IMPLMENTATION • As part of the research effort, specifications from several transportation authorities were collected. All 50 states were contacted for example specifications. The specifications collected are provided in Appendix C. • For states that did not have specifications, interviews were conducted to understand why and the level of interest in developing specifications. Responses indicated that in general, most states desired AMG specifications, but barriers with training, software tools, design guidelines, and perceived issues with liability via electronic data sharing, problems with electronic data delivery, reference datum issues, and needing to pilot test AMG were barriers identified as reasons for not having a specification. • Based on the specifications that were studied, our assessment indicates the following: - AMG will impact the earthwork, subgrade and base course, and paving sections of typical transportation authority specifications. - QC is often considered as a part of the construction services. - QC is often included as a subsection of a full specification sections, - Separate QC guidelines will likely need to be developed for each major AMG category such as earthwork and pavement. • After a critical review of the phrase and heading tables, the following six heading were identified to best characterize the specification language from all the specification documents — general, liability, equipment, responsibilities, measurement, and payment. These headings were selected for inclusion in the guide specification tool. The specification development process described in the FHWA Report “Evaluation of Procedures for Quality Assurance Specifications”, (2004) was used to guide the process of compiling the content for each of the key headings. • The AMG guide specification tool includes a compilation of important key phrases. A letter

NCHRP Project 10-77 146 and number enumerate each line item. The letter corresponds to the first letter of the section header (e.g. the general section is G.01, G.02, etc.). Responsibilities are subdivided into agency (AR) and contractor (CR). A single idea is represented by each line item. In some cases, the basic idea is viewed differently by states. To not omit certain perspectives, nested statements are used to provide optional content in lieu of the primary content or additional content that can be added to the primary content. Brackets with highlighted text, <<xxx >>, are occasionally used to provide an option word or short phrase rather than repeat variations of the primary phrases. Most of the table’s content has been synthesized for purpose of being used as a guide specification. • To use the AMG guide specification tool, it would ideally be reviewed and discussed by agency design and contracting groups and provided to contractors for review and comments. The guide tool is formatted so that it can be printed, marked for items to include, marked to add additional items, and space for adding comments. FUTURE OF AMG • Rapid technological developments are propelling AMG towards new capabilities that are radically expanding and shifting the roles and identities of traditional surveyors, design engineers, agencies, contractors, and equipment providers. New paradigms are emerging for conceptualizing sites, designing new and different projects, constructing projects, and ultimately using and maintaining them. • The future of AMG is one that will likely be abundant with modern technologies, with advanced software, improved data interoperability, and new autonomous machine capabilities. This section of the report highlights what are some of the emerging AMG technologies and presents a creative consider the future at what might be possible. Whatever the future AMG landscape looks like, it will require planning and innovative ways of interaction to garner the full potential of this technology. New partnerships, research and development, and training across the AMG community will be key to accelerating AMG innovation. The concept for an AMG professional is introduced in this context. • Also, building of discussion elsewhere in this report is the topic of data interoperability and future needs. A futuristic description of an AMG land drone is also presented in the context of some of the technical challenges that exist to advancement AMG capabilities to yet an even higher than exists today.

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