Between the Poles

ASCE standards reduce risk and expedite public highway construction projects

What the engineer does during planning and design has a multitude of impacts: traffic disruptions to the public, safety for workers on construction sites, avoiding delays and budget overruns on projects, decreasing risk to contractors, and reducing cost to the rate paying public. It really is a matter of public welfare and that's why the ASCE 38 and 75 standards are engineering standards. What we'd like to do is enter into a world where we we have as reliable information about the subsurface as we do about the above ground and the location of underground infrastructure is well understood in the design stages.  Then we can start applying modern 3D BIM design technologies, virtual design, and new other technologies to enable the construction process to proceed as rapidly as possible with the least amount of risk and rework. And that's going to save everyone money and a lot of headaches.

Regulating the public ROW

With respect to underground utilities the key idea is to avoid, accommodate and then relocate. This will require changing the mindset of agencies such as DOTs that should be regulating work in the public right of way. Currently many DOTs allow the utility operators free rein to build and operate in the ROW. They take a hands off approach saying it is not their responsibility, it's the utilities operators/owners problem. At this point it is generally recognized that this approach no longer works because everybody is accountable when things go wrong and a gas main gets broken and a building explodes. If we can accurately locate, map and accommodate underground infrastructure during planning and design, just as we do using above ground surveys, we expedite the project by taking the risk arising from underground utilities out of the critical path. By speeding up these jobs you can really save a lot of money on major construction projects.

ASCE 38-22 for SUE Surveys

In contrast to the 38-02, the latest version of the 38-22 standard for SUE investigations is both prescriptive and a performance standard. It is prescriptive in that it specifies the minimum actions that must be undertaken to achieve (or attempt to achieve) a particular quality level. As a performance standard it describes the professional judgment that needs to be exercised to determine the appropriate timing, sequencing, location and scope of a utility investigative effort to achieve the goal of reducing utility issues during planning and design by achieving Quality Level B or A for all underground utilities. ASCE 38-22, unlike 38-02, specifies levels of positional accuracy. 

We wanted to provide better definitions so that there's greater clarity in what constitutes a SUE survey.  The SUE survey must be stamped by a professional engineer and In addition be accompanied by an engineering report that goes with the submittals to help lay out what has been found, where issues and discrepancies were encountered, and the things you need to be especially careful about. It includes our recommendations going forward on the project, what you need to consider and  where you may need to do more advanced geophysical investigations or vacuum excavations to better define the design, where you need coordinate closely with utility owners, how to prepare construction documents and plan construction. The liabilities behind this document is significant. To protect the owner, the contractor, and the engineer whoever has provided the SUE data and service must be able to document what they did sufficiently to be able to stand up in a court of law and say, "We met the standard of care."

ASCE 75-22 As-installed

We define the spatial and the attribution properties of the facilities that we want to record, so that at the end of the day, we can actually create a digital twin in a user friendly format and consistent format. We have defined minimum, optional and conditional attributes and the minimum requirements, list the information we must have to create a digital twin or very useful 3D model of our infrastructure in a standardized manner.

In Montana we have a permitting system for work in the public ROW and we can collect these attributes and an approximate alignment at the time of applying for the permit. The person filling out the permit application understands the required attributes and can plug them right in. And then when the actual work is performed, the approximate alignment's upgraded to the actual observation via the survey data. ASCE 75 has been implemented in Montana for several years now and has won both Montana and national engineering awards.

We also support absolute spatial positioning and have have a framework for data exchange by having a standard datum. At the National Oceanic Atmospheric Administration (NOAA), this is the same thing we do for nautical charts and hazards to navigation. We're just applying it to hazards to excavation. Everything is referenced to the National Spatial Referencing System. That gets rid of all the distortion that happens when you're trying to take something on a sphere and flatten it on a flat plane. You get distortions, there's different projections, state plane, county coordinates, UTM and they all distort the image. By having everything referenced to the National Spatial Referencing System, when you bring it together, it's going to go in the same spot every time. And it accounts even for plate tectonics and crustal drift ln places like California, Whenever you're turned on your GNSS system, you're tied into the National Spatial Reference System. It is being upgraded and the next version should come out in another year.

ASCE 75 specifies levels of positional accuracy. There's an accuracy table that goes with the standard, which we basically piggybacked off CSA S-250, the Canadian standard. We have CSA S-250 people on  our 75 standards committee. They also told us three things that they wish they had included with CSA S-250; make it a digital standard, secondly make it 3D and thirdly include above ground infrastructure with the standard. So we made sure we brought those into ASCE 75-22.

The Open Geospatial Consortium (OGC) has adopted both ASCE 38 and 75 as important input to their Model for Underground Data Definition Initiative (MUDDI ). The MUDDI model provides a base conceptual data model for interoperability and data exchange.  It is being adopted world wide including by the NUAR initiative in the UK, the UNUM project in New ,and other jurisdictions.

Securing sensitive information

Data stewardship includes issues of sensitive and secure information.  Here in the U.S, we're using 49 CFR Part 1520, which talks about how to manage sensitive secure information that TSA has determined to be Sensitive Security Information, as defined in § 1520.5. (This part does not apply to the maintenance, safeguarding, or disclosure of classified national security information.) It's a big issue with many utility owners. They don't want that information available to everyone. The 49 CFR Part 1520 guidance defines what information needs to be kept secure and that has helped alleviate the data protection concerns of the utility owners.

Conclusion

With the imminent availability of the ASCE 38-22 and 75-22 standards, every underground utility segment that's depicted can be assigned Quality Levels based on ASCE 38-22 for existing infrastructure or from the ASCE 75-22 "As-installed" standard for newly installed infrastructure. For example, in Colorado both draft standards are mandated for all work in the public ROW. This enables a world where we we have as reliable information about the subsurface as we do about the above ground and the location of underground infrastructure is well understood in the design stages. Then we can start applying modern design technologies to produce better designs which enable the construction process to proceed as rapidly as possible with the least amount of risk and rework.

This post is based on Phil Meis' (UMS and ASCE) talk at the Subsurface Utility Mapping Strategy Forum (SUMSF).

SUE proposed as foundation for best practices for utility coordination on P3 projects

Public infrastructure projects frequently experience delays and cost overruns - often due to underground utilities - but delays and cost overruns are rare on P3 projects. Furthermore because P3 projects include not only the design/build part of the project but also the operate and/or maintain phase, P3s deliver better designed facilities that can be efficiently operated and maintained during the contract term, which can extend from 15 to 30 or more years. To help public-private partnership (P3) project stakeholders develop an efficient and consistent process for coordinating utilities, the Transportation Association of Canada (TAC) has developed a best practices guide specifically targeted on P3 projects. Essential to reducing the risk associated with underground utilities is knowing their accurate, up to date location.  The TAC guide makes subsurface utility engineering (SUE) the foundation for coordinating utilities on P3 public infrastructure projects.

Background

Public infrastructure projects frequently experience delays and cost overruns often due to underground utilities. The reason is that on a typical public construction project the government is responsible for project risks that add time and money to an infrastructure project.

Canada has developed a reputation for successfully delivering infrastructure projects using a public-private partnership (P3) approach. P3s are used to deliver an infrastructure project such as building and expanding roads, bridges, transit systems, and other public infrastructure.

On a P3 project the public sector always owns the infrastructure. The government determines when and where to build the project, its scope, and its budget. A competitive process is used by the government to select a private partner. The private partner designs, builds, finances, maintains and/or operates the public infrastructure. Delays and cost overruns are rare on P3 projects, as this approach allocates risks and responsibilities to the public and private sectors based on their areas of expertise. For example, the public sector bears the risk for changes in laws and regulations and the private partner bears the cost of construction delays. Because P3 projects include not only the design/build part of the project but also the operate and/or maintain phase, P3s deliver better designed facilities that can be efficiently operated and/or maintained during the contract term, which can extend from 15 to 30 or more years.

SUE proposed as foundation for coordinating utilities on P3 projects

There is a trend in legislation and regulation which on one hand may provide strong measures for compelling utilities and other infrastructure owners to improve locating, utility treatments and relocations, on the other provide encouragement for a collaborative approach among utility owners and government agencies which replaces the traditional regulatory mechanisms involving fines and other penalties for noncompliance. On P3 projects in particular the key to successful utility coordination is a team approach, with each member having a role in completing their portion of the project. The players on the team are the project owner, typically a government agency that funds the project; the ROW owner, the government agency responsible for maintaining the public ROW; the Utility Coordinator (UC), responsible for utility coordination on all phases of the project; the designer, who designs the P3 project at different stages ranging from conceptual design through detailed design; and utility agencies, the owners of public or private utility infrastructure who are often also the Project Owner. One of the key challenges for utility agencies is providing accurate records of their existing infrastructure to the Project Owner.

SUE and as-built standards

The foundation for the best practices proposed by TAC for utility coordination is subsurface utility engineering (SUE).  Standard practice for SUE investigations is based on American Society of Civil Engineers (ASCE) 38, first released as ASCE 38-02 but soon to be replaced by ASCE 38-21. The ASCE 38 standard establishes quality levels for underground utility information that all parties can use to evaluate the accuracy and reliability of underground utility location data.

The standards for "as-builts" for newly installed and relocated infrastructure are ASCE 75 in the U.S. and CSA S-250 in Canada.  For example, in Colorado both ASCE 38 and 75 are mandated, which means that every underground and above ground utility segment that's depicted could have either a utility quality level based on ASCE 38 for existing infrastructure or a utility accuracy level from the ASCE 75  "as-constructed" standard for newly installed or relocated utility infrastructure.  In Canada it's a little different. Every utility segment could have either a utility quality level based on ASCE 38 for existing infrastructure or a utility accuracy level from the CSA S-250 standard for newly installed or relocated infrastructure.

Application of SUE over project lifecycle

The TAC guidelines breaks the construction process down into phases: Planning, RFP Document Preparation, In-Market Design, Project Implementation and Post-Construction and identifies the roles and responsibilities of each team member during each phase with respect to utility coordination. The TAC guide describes how SUE practice is allocated over the different phases of the project.

During the Planning Phase the Project Owner is responsible for putting together a base plan of the general construction project area that is adequate for the requirements of utility coordination. The base plan is  forwarded to all impacted Utility Agencies (public and private), with a request for each utility to provide maps of their utility infrastructure based on the Utility Agency’s current records in the proposed project area. This information represents some of the QL-D (from utility records) and QL-C (from site visits) information for the project and is typically of limited quality. It is often  inaccurate, out of date or simply missing, which is frequently he case for abandoned infrastructure. At this stage it is critical that the utility agencies flag high risk utilities such as high pressure transmission lines.  Preliminary SUE investigations, providing QL-B (using remote detection technology) and/or QL-A (potholing), may be completed to validate and improve the quality of the utility information. Based on all of this information the Utility Coordinator creates a preliminary Utility Conflict Matrix that lists potential utility conflicts and relevant information about the utilities identified.  At the completion of the Planning Phase the approximate location of existing utilities and potential future utility infrastructure and possible relocations of high risk infrastructure should be known.

The Request for Proposal (RFP) Documentation Preparation Phase involves preparing the final RFP documents that will be made available to potential bidders. Included in the activities at this stage is the development of a Reference Concept Design (RCD) which may require that additional preliminary SUE investigations be performed to a quality level required for the Project’s In-Market Design Phase. The RCD is used by the Project Owner and Utility Agencies to conduct utility conflict assessments.  If a utility is identified to be in conflict with project works, further SUE QL-A investigations may be required to verify whether it indeed represent a conflict. The RCD design augmented by SUE information plays a significant role in the development of a RCD Utility Conflict Matrix which is a key component of the RFP becausee it provides crucial information about potential utility conflicts to the bidders.

The In-Market Design Phase (or Bid Phase) includes all activities required to deliver a preliminary design which forms the basis for preparing bid estimates.  Starting with the RCD Utility Conflict Matrix, each bidder prepares their own Utility Conflict Matrix based on their RFP submission design.  Knowing the location of existing utility infrastructure is crucial for the bidder to estimate scope of work. To help identify the location of existing utilities – both buried and overhead – the bidders use the information available as background documents provided with the RFP including utility records for private and public utilities, the RCD Utility Matrix, SUE reports provided by the Project Owner, RCD designs, preliminary utility relocation designs from Utility Agencies, and visual inspection and survey information. Since SUE often extends over more than one phase, it is essential to commence SUE investigations early in the Planning Phase to ensure the information is available to the proponents prior to and not beyond the initial In-market Design.  Each bidder is responsible for identifying the location of all existing utilities within the limits of construction, for coordinating any required utility relocations, and all the utility relocation and/or protection work necessary to accommodate utility coordination for the P3 project. During this phase estimating activities may require additional preliminary SUE investigations.  The In-Market Design Phase ends with technical and financial submissions from bidders to the Project Owner. Each submission is evaluated based on a technical and financial assessment and the Project Owner awards the P3 Contract to the successful private partner.

The Project Implementation Phase includes all activities associated with delivering the project from contract award through to completion of construction.

The initial objective of the private partner is to complete the preliminary design to a 30% level. To achieve this requires conducting an additional SUE investigation with the objective of achieving QL-B and QL-A for all underground infrastructure within the project limits.  This is required to ensure that all the required information has been collected to complete the Detailed Design.  This SUE investigation builds on the preliminary SUE information captured during the Planning and In-Market Design Phases.  Based on the complete SUE data the private partner creates a Utility Conflict Matrix that can be maintained and updated regularly to ensure that the latest conflict data is always available to project stakeholders. 

It is also extremely important for each Utility Agency to have access to the latest detailed design and SUE data to enable them complete their relocation designs early in the process. The initial objective of design is to complete the Detailed Design to a level that is sufficient for the utility companies to initiate their respective detailed designs for their relocation work.

After design and during construction, conflicts with unknown utilities may be encountered. It is essential that they be reported immediately to the Utility Coordinator who will initiate a field conflict resolution process. The private partner and the Utility Agencies need to notify the Utility Coordinator at the first indication of a delay to their relocation schedule due to the unknown conflict. The Utility Coordinator is responsible for assessing the impact of the delay on the overall Utility Relocation Coordination Plan and the private partner will follow up to determine the impact on the overall project schedule.

Once relocation construction is completed it is important to ensure that the records submitted for all relocated underground infrastructure are accurate. Utility Agencies are required to prepare “As-Built” drawings to be submitted to the private partner that are compliant with CSA S-250 quality requirements.

Operation and maintenance (O&M) typically represents 80% of the lifetime of an infrastructure facility. In the Post-Construction Phase under a Design, Build, Finance and Operate or Maintain (DBFO or DBFM) P3 model, the private partner is responsible for the operation and/or maintenance of the newly constructed infrastructure for 10 years or more. The O&M responsibility includes all activities necessary to operate or maintain transit facilities, toll roads and other infrastructure.  For civil infrastructure this includes supporting One Call notifications.  An advantage of DBFO and DBFM P3 projects is that it is in the financial interest of the private partner to control O&M costs by optimizing O&M activities.  This includes ensuring that accurate, up to date and complete location data for underground utilities and other infrastructure within the project limits is collected and maintained throughout the project life-cycle.

Application of SUE and as-built standards

During the Planning and In-Market Design (Bid) phases preliminary SUE investigations are conducted to collect and compile underground location data, typically to QL-D and QL-C quality levels. Building on these preliminary SUE investigations, the best practices for P3 projects proposed by the TAC requires the completion of a comprehensive SUE survey that achieves QL-B or QL-A quality levels for all underground infrastructure within the project limits. The TAC guidelines also require that as-builts submitted for all relocated infrastructure be compliant with CSA S-250, which is the Canadian as-built standard, corresponding to ASCE 75, the as-constructed standard in the US.

Conclusion

The guidelines for best practices for utility coordination on P3 projects provided by the Transportation Association of Canada (TAC) makes subsurface utility engineering (SUE) the foundation for reducing the risk associated with underground utilities. The objective of SUE investigations is identifying and determining the accurate, up to date location of underground utilities including abandoned infrastructure. The TAC guidelines also require capturing and maintaining accurate location data for relocated utilities.  Accurate and up to date location data for all underground utilities is critical for controlling costs during the O&M phase, which typically represents 80% of the lifetime of an infrastructure facility.

Colorado leads in mandating subsurface utility engineering (SUE) surveys for public civil engineering projects

A major gap in the construction process is the unavailability of reliable information about the location of underground utilities during the design stage of civil engineering construction projects such as highways and pipelines. All states and provinces in North America have one call legislation designed to reduce underground utility damage during actual excavation, but the legislation does not provide for making underground records available to inform the design phase of construction projects. Colorado is the first state/provincial jurisdiction in North America and one of the first in the world to mandate a subsurface utility engineering survey (SUE) at the pre-construction stage. At the Canadian Underground Forum in April, Rob Martindale, Utilities Program Manager at the Colorado Department of Transportation (CDOT) and a Professional Land Surveyor, described the process by which SUE surveys became law in Colorado.

Several jurisdictions around the world have undertaken initiatives to integrate underground infrastructure location data and make it available to all stakeholders. Among the leaders in this effort are the National Underground Asset Registry (NUAR) project in the UK, Singapore's Digital Underground initiative, and the State of Colorado. While the UK and Singapore are in the initial stages of implementation, Colorado has already enacted and implemented legislation and regulations which are transforming underground infrastructure location data for public civil engineering projects across the state.

Mapping underground infrastructure is benefiting from accelerating innovations in technology in detecting, locating, capturing and sharing subsurface utility location data. Experience has shown that enabling these technical advances to permeate and transform business practices in the entire construction industry requires government intervention. The key stakeholders in civil engineering construction are government transportation agencies, utility regulatory agencies, utility and telecom network owners and operators, civil engineering consultants and construction contractors.

Rob Martindale is responsible for improving CDOT's subsurface utility mapping program and utility data management systems. He has been involved from the beginning in the legislative and regulatory processes that are transforming underground infrastructure data in Colorado and is able to provide an insider's perspective on how this process unfolded in Colorado.

As anyone who is involved in civil construction knows, the historical problem with locating underground infrastructure is that utility company records (aka network documentation) are inaccurate, old or outdated, lost, or simply just never existed to begin with. The records that do exist are often inconsistent and the quality of the data is unknown. Records are kept in different data models and formats, typically as CAD drawings, GIS files, paper copies, and PDFs. Some drawings are schematics rather than records of actual utility location. Virtually all of the data is 2D so depth is unknown. Another complicating problem is that in general each utility uses a different base map making it difficult to integrate data from different utilities on a single map. These issues make compiling a reliable map of underground infrastructure in preparation for a civil construction project a challenge. The result is that underground utilities are ignored until excavation begins. As a consequence according to the Federal Highway Administratiion (FHWA) underground utilities are the biggest cause of delays in highway construction projects.

Recognizing the risks associated with underground utilities, CDOT could see that one way to reduce risk was by enabling more reliable and efficient subsurface utility mapping. Since the state is the legal custodian of the public right of way, it had the power to enforce regulations for utility and telecoms with network facilities in the right of way. To CDOT having more reliable location data and more comprehensive attribute data about each utility such as size of pipes and cables and types of material would make for more efficient and productive coordination with utility owners. To achieve this CDOT's vision was a single platform where all underground location and attribute data would be accessible to all stakeholders working in Colorado on current and future civil construction projects.

New legislation revising Colorado's one call statute

In 2015 the Pipeline and Hazardous Materials Safety Administration (PHMSA) conducted an assessment of the Colorado one call system that resulted in a report that identified the lack of an enforcement mechanism as a major impediment to effective prevention of damage to underground infrastructure in the Colorado one call legislation. The PHMSA review had implications in a number of areas including future Federal funding. Then in April 2017, there was a gas explosion in Firestone, Colorado that resulted in fatalities and attracted a high degree of public attention. Recognition that that the incident could have been prevented further prioritized the issue for the Colorado legislature. The result was growing pressure from many construction stakeholders including the Colorado Contractors Association, the American Council of Engineering, American Society of Civil Engineers (ASCE) and CDOT which ultimately attracted the attention of politicians. The initiative was taken up and made a top bipartisan priority by two representatives in the Colorado legislature, Senator Ray Scott, Republican, and Senator Kerry Donovan, Democrat. In 2018 they co-sponsored a bill to revise Colorado's one call statute. The revised statute was signed by the Governor on May 25^th and became law in August, 2018.

The legislation included several important provisions. First and foremost the new law required subsurface utility engineering (SUE) surveys on most public civil engineering projects. It requires the project owner, CDOT or another agency, to notify the Colorado one call center for all projects that require a SUE survey. Furthermore after being notified by the one call center utility owners are required to provide their best available records of their infrastructure in the project area within a 10 business days. The project owner is then required to conduct a SUE survey at their own expense and provide the results showing the location of all underground infrastructure and assigned the ASCE 38 quality level to CDOT. Importantly, the SUE document must be stamped (signed) by a PLS or PE to ensure accountability. Standard SUE practice is to achieve at least ASCE Quality Level B for all underground utilities. In the case of conflicts with a new gravity-fed systems it is expected that test holes will be dug to locate and identify conflicts with existing utilities. Furthermore Colorado became an ASCE 38 state. The law requires ASCE 38 to be used on SUE surveys. Currently that means 38-02, but when the requirement will be ASCE 38-21 when that version is released.

For excavation the Colorado 811 notification process was also modified. It allows the utilities two days to visit the site and mark utilities on the ground before excavation begins.  In addition the new law mandated that all newly installed utilities must be electronically locatable.

Another important provision of the new law was the creation of a one call enforcement mechanism. This was in response to the PHMSA assessment of of Colorado's original one call legislation. The new legislation created an Underground Damage Prevention Safety Commission with the power to levy penalties on utilities that were non-compliant with Colorado's one call requirements. For example, if a utility company fails to provide its best available records within 10 business days, the commission is empowered to levy a fine of up to $75,000.

Integrating SUE into the construction lifecyle

Beginning in August 2018, CDOT adopted a five stage utility project delivery process that includes SUE activities and utility coordination processes.

In the planning stage a design scoping review (DSR) determines whether the project requires a SUE survey. There are four criteria for a project to require a SUE survey; it must be a public project, it must be primarily a horizontal project, not a vertical project such as a building, excavation must exceed two feet in depth and the site must encompass a contiguous 1000 square feet, and the project must be designed by a professional engineer. Based on these criteria more than 95% of CDOT projects meet the requirement for a mandatory SUE survey. In addition at this stage Colorado one call (CO 811) must be notified and utility owners are required to provide their best available records within 10 days. Also in the planning stage a SUE vendor i selected.

In the 0 - 30 % design stage an initial SUE review is conducted to identify all underground infrastructure to ASCE Quality Level D, C, or B. At this stage the SUE survey involves records research, geophysical investigation, professional engineering judgment, knowledge of construction practices and utility design principles all of which are used to determine the quality level to be assigned to each segment of existing utility information.

During the 30 - 90% design stage the goal is to complete the necessary remote detection and test holing to achieve QL B or A for all underground assets at the site. A technical innovation that CDOT has adopted is a mobile and cloud-based hybrid GIS/surveying system for recording underground utility location and other data. The data collected by the SUE vendor is entered into this system which allows the SUE data to be shared among all stakeholders and to be available throughout the entire construction lifecycle.

As an example a project might start with a design in Microstation. The initial SUE data is used to identify potential conflicts each of which is flagged with QL D, C, or B to show the assessed reliability of the location data. Using existing utility data compiled by the initial SUE survey makes it possible to to avoid potential utility conflicts at a very early stage.  This helps avoid costly or time consuming utility relocations. It also makes it possible to identify critical infrastructure and conflicts that may require test holing.  During the 30 - 90% design stage the SUE vendor attempts using remote sensing technology and test holing to achieve QL B or A all underground assets at the site. At this advanced design stage detailed conflicts in 3D can be identified to enable remedial action to be undertaken.  SUE data can be pushed back to the CAD environment for redesign or for utility relocations. SUE data is also made available on CDOT's mobile app for contractors to use in the field to resolve discrepancies in utility surface markings from locating activities resulting from one call notification. The handheld app also makes it possible for contractors to record new test holing that they have conducted and to document utilities exposed during excavation activities.

Colorado has become a model for jurisdictions who have recognized the human and economic cost of inaccurate, out of date and missing data about the location of underground infrastructure. Advances in technology are enabling a revolution in how we detect, capture and share reliable information about the location of underground infrastructure, but, as Colorado is demonstrating, transforming business practices in the construction industry as a whole requires legislation and regulation.

This post is based on Rob Martindale's talk at the Canadian Underground Forum. You can listen to Rob's talk on the GeoIgnite CUF Youtube channel. 

Canadian Underground Forum begins tomorrow

You can see the program for April 29 and 30 and register here.

Speaker lineup

One of the early innovators in applying LiDAR to mapping underground pipelines, Joseph Hlady, President at Lux Modus in Calgary, Alberta will explain n his keynote the benefits that his technology has brought to the oil and gas pipeline industry. Another early innovator is Otto Ballintijn, CEO of Reduct who has developed inertial or gyro technology for mapping underground pipe networks. In his keynote he will explain the evolution of the technology including the concept, operational method, and data output of gyro mapping technology. A number of jurisdictions around the world are developing digital twins at the urban, regional and even national level. Alex Shalash of UEVO will discuss creating a city subsurface infrastructure map which unifies fragmented information and produces an intelligent digital twin. Danny Petrecca of Locusview, an early leader in capturing and managing underground data in the gas industry, will review why as-builting still remains paper-based and discuss a digital construction solution that stitches together existing technologies to create the reliable digital twin that utilities need in the age of the smart grid.

Our chief guest speaker is Jim Anspach, Chair of the ASCE 38 standards group, who will bring us up to date on the imminent 38-21 utility as-built standard. Carsten Roensdorf and Neil Brammall will introduce the Open Geospatial Consortium's work in progress, the MUDDI standard for exchanging location data about underground infrastructure. Lawrence Arcand, who has led Subsurface Utility Engineering (SUE) investigations on a national level since 2003, will provide an overview of the Canadian standard CSA S250:20 Mapping of underground utility infrastructure.

Rob Martindale, Program Manager - Utilities/Railroads at the Colorado Department of Transportation, will present an overview on how a mix of legislation and regulation has enabled Colorado to revolutionize the capture and sharing of accurate underground utility location data. Page Tucker, President & CEO at ProStar which implemented the mobile and cloud solution adopted by the Colorado DoT will speak about how the partnership between Colorado DoT and Prostar made this successful. One of the remarkable new technologies applied to mapping underground infrastructure was developed by 4M-Analytics. Harel Dan, Head of GIS and Remote Sensing, and Ophir Wainer, Director of North America Business Development, will explain how 4M-Analytics uses satellite and aerial imagery to map underground infrastructure. Leica Geosystems' IDS Georadar was one of the early innovators in ground penetrating radar. Simon Pedley, Detection Ambassador at Leica Geosystems will talk about some of the innovations in hardware and software that Leica Geosystems has developed in the last couple of years.

Government has a crucial role to play in locating and mapping underground infrastructure. Gord Reynolds and Alon Gat will discuss how Infrastructure Ontario partnered with Metrolinx and the Ministry of Transportation to establish the Utility Coordination Program (UCP), a new initiative which oversees the development of utility relocation standards and the supporting process to improve the location, treatment and relocation of utility infrastructure. Gordon McElravy, of buildingSMART Canada, will discuss buildingSMART's efforts in implementing the Municipal Infrastructure Council Program to encourage building information model (BIM) initiatives at the municipal level. Capping the first day of CUF Prashant Shukle, who was responsible for mapping and earth observation in the Canadian government for many years, will moderate a panel discussion on the role of government in underground infrastructure with panelists from the State of Colorado, the U.K. Government's Geospatial Commission, Public Services and Procurement Canada, and Infrastructure Ontario.

A revolutionary source of underground utility location data for SUE surveys

Return on investment (ROI) studies of subsurface engineering utility engineering (SUE) surveys applied to highway construction projects conducted since the late 1990s have consistently revealed a large return-on-investment from conducting SUE surveys as part of highway construction projects.  Studies have found that the major benefits of SUE surveys are improved construction efficiency, greater probability of on-time and on-budget project completions, fewer and shorter utility service outages and less traffic disruption and delays for the motoring public. Recently jurisdictions such as Colorado have mandated SUE surveys on all public civil engineering projects.

The objective of a SUE survey is to identify and locate all underground infrastructure in the area of the proposed project to ASCE 38-02 Quality Level B or better. Currently SUE surveys rely on on-site detection technologies such as electromagnetic (EM), ground penetrating radar (GPR), and other methods to remotely detect underground utilities.  Potholing is also routinely conducted as part of a SUE survey to confirm the identification and location of utilities that have been detected by remote sensing technologies.

Using remote detection methods and potholing requires "boots on the pavement" which raises safety as a major concern when conducting a SUE survey.  EM devices are typically handheld wands and GPR is usually mounted on pushcarts. Data acquisition occurs at a walking pace.  Furthermore the reliable interpretation of GPR scans requires an experienced geotechnical practitioner. Together these factors make SUE surveys slow, laborious processes with serious safety issues.

I have recently come across a technology innovation developed by 4M-Analytics that could provide SUE practitioners with a source of data without the major disadvantages of traditional remote detection methods; it is safer because it does not require boots on the pavement, can reliably provide accurate locations, can be conducted without disrupting traffic, and can be generated much more rapidly than the traditional on-site remote detection methods. Intended for linear civil engineering projects such as pipelines and transportation routes 4M-Analytics' technology utilizes high-resolution satellite and aerial imagery, computer vision algorithms, and training sets for machine learning developed for different biomes, including forests, grasslands, and deserts. The deliverable to the SUE practitioner is a complete, accurate and up-to-date utility conflict map showing the location of all underground utilities and pipelines intersecting a proposed civil engineering project.

SUE is rapidly growing in importance for civil engineering projects. This revolutionary approach to locating underground infrastructure, which utilizes the huge volume of aerial and satellite earth observation imagery that has been built up over the past decades together with machine learning, could provide an important source of rapidly produced, safely acquired, and reliable underground location data for SUE practitioners.

Scotland's system for sharing location information about underground infrastructure to be mandatory

Scotland is one of the leading jurisdictions in developing a nation-wide collaborative system for sharing information about the location of underground infrastructure among stakeholders involved in road construction including roads authorities, utility and telecom network operators, and Transport Scotland. The Scottish Vault system was implemented by the Scottish road works community on a voluntary basis in 2012 and will soon become mandatory. There is a dial before you dig system in Scotland, but it is being used less and less as network operators and roads authorities are switching to the Vault system.

Background

Underground utilities and other infrastructure are a major cause of highway construction schedule and budget overruns. In addition to construction delays, damage to underground utilities during construction makes every construction project a potential disaster site with risk for workers and the public. Every year, in excess of four million holes are dug in UK roads to repair assets, provide connecting services to new premises and to lay new cables and pipes. Failure to identify accurately the location of existing buried assets results in numerous practical problems, costs and dangers for utility owners, contractors and road users.  Location and attribute data on underground services can be very poor, in some cases especially for older assets even non existent. Improving mechanisms of integrating and sharing knowledge on utility assets and the location of street works are expected to lead to a reduction in the amount of street works in the UK by improving both the co-ordination of works and the quality of the information shared.

I recently had the opportunity to chat with Kat Quane, Road Works Policy Manager at Transport Scotland about Scottish initiatives to reduce underground utility damage.

Scottish Road Works Register

The Scottish Road Works Register (SRWR) is a system used by all roads authorities and excavators in Scotland to coordinate construction projects. For over 30 years, it has enabled them to share details of planned and ongoing construction projects including the location of underground infrastructure. Historically underground utility information has been shared by providing maps by email, websites, or distributed on CDs.

The Scottish Road Works Commissioner is an independent public official responsible to the Scottish Parliament. The Commissioner's aim is to improve the planning, co-ordination and quality of road works throughout Scotland.

Development of the Vault system

The Scottish Community Apparatus Data Vault (Vault) is intended to make underground asset information accessible to road authorities and network operators. organizations that have a statutory right to dig up in the public right of way. The participants in Vault are restricted to organizations that participate in the Scottish Road Works Register (SRWR) and have a statutory right to dig in the public right of way. In Scotland there are about 150 utilities, half of which have a statutory right to dig. The aim of the service is to allow timely access to information about all underground assets from a single centralized location to ensure the safety of workers in excavation as well as the public. Vault is funded as part of the overall SRWR funding.

The U.K. Mapping the Underworld (MTU) project, initiated in 2004 and largely funded by the Engineering and Physical Sciences Research Council (EPSRC) and involving the University of Birmingham, University of Bath, British Geological Society, University of Leeds, Newcastle University, University of Sheffield, University of Southampton, and UK Water Industry Research (UKWIR), sought to address the serious social, environmental and economic consequences arising from an inability to locate buried utility service infrastructure without resorting to potholing. As part of MTU initiative the University of Leeds developed the Vault system as part of the VISTA (Visualizing Integrated Information on Buried Assets to Reduce Street Works) project. The Vault system was adopted in Scotland in 2012.

The systems provider of the Scottish Road Works Register and Vault is a private company Symology. Data is provided by network operators and roads authorities via an extract, transform, load (ETL) process.  One of the objectives of Vault is to be able to integrate data in a variety of format from different GISs. The data in Vault not only shows the location of underground infrastructure but also the type of equipment such as gas, telecoms, electricity, water and others along with contact details for the owners of the facilities.

At a minimum utilities are expected to refresh their data four times a year. In Scotland there is no national statutory limit on as-built and update backlogs. For volatile data sources data is refreshed every 2 months. However, U.K. regulators may regulate this. For example, Ofgem requires as-built and update backlogs to not exceed 42 calendar days (30 business days).

Data protection

Scotland has a history of working collaboratively. This tradition has enabled utilities and telecoms to share details of planned works in the national register up to three months ahead of deployment. Non disclosure agreements have not been required in works planning – since everyone is subject to the same rules, and everyone can see everyone else’s data, no one is commercially disadvantaged. Road Works data recorded on the Scottish Road Works Register (SRWR) is available as open data. The SRWC is subject to public body rules on cyber security and all participants must meet the highest levels of data security.

The information accessible through Vault is only available to users of the Scottish Road Works Register.  The Scottish Road Works Commissioner has restricted access to the register to the roads authorities and excavators working in Scotland. Data is not shared with any third parties without the express prior permission of those that supplied the data. Access to the Vault system to contractors requires vetting by one of the members, either a network operator or roads authority. Access to the system is restricted by email and password. The system can be accessed from a notebook or a handheld in the field.

Incident reporting

Reporting underground utility damage is not part of the Vault mandate. Near misses, injuries and fatalities are reported to Health and Safety of the U.K. Government. For the last 30 years underground utility damage is reported to the “Road Works Register”. While reporting is not mandatory, since 2005 this register has been designated a legal document, and represents a permanent record that can be used in civil litigation to determine liability in the case of damage. Not all incidents of damage are reported, but it is likely that the more serious instances are. An annual report is published by the Scottish Road works Commissioner based on the data in this register, but number of incidents of underground utility damage is not reported, nor is the estimated costs of damage estimated. However the data is available and the number of incidents can be determined. Kat estimates that the number of incidents is in “hundreds”.

Data quality

There is currently no requirement relating to data quality on the data submitted to Vault by network operators and local government. However, the data submitted by utility operators and roads authorities in Scotland data is generally compliant with the U.K. data quality standard for locating underground utilities PAS 128 (2014). Furthermore, many utility operators including Scottish Water, Scottish Gas, and Scottish Power are making a concerted effort to improve the quality of the data that is submitted to Vault and Kat reports that data quality is improving. An important benefit of a system like Vault that enables all underground utility data to be seen in a single view and compared with what is exposed during excavation is that it makes inaccurate data very apparent. There is greater awareness of the value of reliable data for reducing the risk of damage during construction, planning and design, preventative maintenance and reducing liability costs.

Vault will soon be mandatory

In 2012 the Vault system was deployed in Scotland on a voluntary basis.  Last year a bill to make participation mandatory in Vault was passed by the Scottish Parliament and has received royal assent.  The COVID-19 pandemic has delayed implementation of the new legislation, but it is expected to begin as soon as the economy reopens.

This is a ground-breaking national initiative involving legislation, regulation, new technology and especially collaboration between stakeholders to address one of the chief causes of highway construction delays, cost overruns and injuries to workers and the public.  The Scottish Vault system addresses the challenge of sharing the location of underground infrastructure among stakeholders involved in civil construction projects and is an important step toward reducing the risk of underground utility damage.

Large ROI from subsurface utility engineering (SUE) for highway construction projects

Return on investment (ROI) studies of subsurface engineering utility engineering (SUE) surveys applied to highway construction projects conducted since the late 1990s have consistently revealed a large return-on-investment from conducting SUE surveys as part of highway construction projects.

One of the first in 1999 by Purdue University and sponsored by the US DOT Federal Highway Administration (FHWA) identified 21 categories of cost savings that could result from including a subsurface utility engineering (SUE) survey in construction projects. Only some of these could be quantified and it was estimated that the qualitative benefits exceeded those that could be quantified. It was estimated that SUE surveys resulted in a construction savings of at least 1.9 percent over the traditional approach of relying on as-builts and (above-ground) site surveys for identifying underground utilities.  Using the national expenditure in 1998 of $51 billion for highway construction (FHWA), it was calculated that requiring SUE on road construction projects could result in a national savings of at least $1 billion per year.

A subsequent reanalysis of the same Purdue data estimated that the ROI was $12.23 for every $1 spent on SUE. Furthermore the cost of conducting a SUE survey was estimated at 1.39% of total project costs. In 2007 a study for PennDOT and USDOT found an ROI of 22.21 : 1. 

The most recent ROI analysis sponsored by PennDOT differed from previous analyses by including both SUE and non-SUE projects. It calculated an ROI of 11.39 : 1. The largest contributor to the cost savings attributed to SUE was a 40.33% reduction in utility relocation costs. Utility relocations were avoided or reduced by providing engineers/designers with accurate underground information in the early stages of design. The second largest savings was 29.46% in reduced construction and design costs. SUE enables designers to design efficiently and accurately with reliable information, so that design time can be saved and unnecessary construction work can be avoided or reduced. The cost of conducting a SUE survey was estimated to be 1.65% of project cost.  

These ROI studies show that SUE can provide accurate utility information with important project benefits at reasonable cost.

Year	ROI	Cost of SUE (% of project cost)	Description	Sponsoring agency	Source
2012	11.39:1	1.65%	Study of 22 SUE and 8 non-SUE projects	PennDOT	Yeun J. Jung, Evaluation of subsurface utility engineering for highway projects: Benefit–cost analysis, pages 111-122 in Tunnelling and Underground Space Technology Volume 27, Issue 1 Pages 1-168 (January 2012)
2012	16:1		Study of one SUE project	Region of Lombardy
2007	22.21:1	0.6 %	Study of 10 SUE projects	PennDOT/USDOT	SUBSURFACE UTILITY ENGINEERING MANUAL PennDOT/MAUTC Partnership, Work Order No. 8 Research Agreement No. 510401 FINAL REPORT August 20, 2007 By S. K. Sinha, H. R. Thomas, M. C. Wang and Y. J. Jung
2004	3.41:1		Study of nine SUE projects	Ontario Sewer and Watermain Contractors Association	Osman, Hesham, El-Diraby, Tamer E., 2005. Subsurface Utility Engineering in Ontario: Challenges & Opportunities. A Report to the Ontario Sewer & Water main Contractors Association, October 2005.
2004	12.23:1	1.39%	Reanalysis of 71 SUE projects	ASCE based on USDOT data	Jeong, H.S., Abraham, D.M., Lew, J.J., 2004. Evaluation of an emerging market in subsurface utility engineering. ASCE, Journal of Construction Engineering and Management 130 (2).
1999	4.62:1	0.5 %	Study of 71 SUE projects	USDOT	Lew, J.J., 2000. Cost Savings on Highway Projects utilizing Subsurface Utility Engineering. Federal Highway Administration, Washington, DC.

Pennsylvania Department of Transportation 2012

A definitive study of twenty-two projects utilizing subsurface utility engineering (SUE) and eight non-SUE projects from Pennsylvania Department of Transportation (PennDOT) districts has revealed that $11.39 can be saved for every $1 spent on SUE. The cost of conducting a SUE survey was estimated at 1.65% of total project cost. Eleven direct and indirect costs where SUE would lead to savings were considered in the analysis; utility relocation cost, utility damage cost, emergency restoration cost, traffic delay cost , business impact cost, user service cost, environmental impact cost, information gathering and verification cost, legal and litigation cost, efficient utility design and construction, and other utility related costs and benefits.

On the expense side two kinds of costs are involved in conducting a SUE survey. One is the use of geophysical techniques such as EMI and GPR to identify the location of underground utilities and other objects. The other is potholing (using safe excavation techniques) to confirm the location of the utilities and objects identified. In this study for the projects utilizing SUE, costs were obtained directly from project accounting. For the projects that did not use SUE, costs are estimated from interviews, historical data, and individual project studies.

For the twenty-two projects where a SUE survey was conducted, all underground utilities and other objects were located to ASCE 38-02 quality level A (potholing) or B (EMI and GPR). For the eight projects utilized traditional methods, the location of underground networks was estimated to ASCE quality levels C (site visit) and D (as-builts).

Previous ROI studies of SUE only used projects where SUE surveys were performed to quantify the cost savings of SUE. In this study, non-SUE projects were used to determine the cost savings of SUE because direct costs incurred by problems that would have been avoided by SUE can be considered as SUE benefits. The results of the study revealed that $11.39 can be saved for every $1 spent on SUE on road projects.

The top cost savings that were found are as follows:

1. 40.33% reduction in project relocation cost by providing accurate underground information in the early stages of design
2. 29.46% reduction in construction and design costs - SUE enables designers to design efficiently and accurately with reliable information, so that design time can be saved and unnecessary construction work can be avoided or reduced.
3. 9.59% reduction in redesign costs
4. 9.08% reduction in delay costs due to relocation
5. 6.81% reduction in delay costs caused by emergencies
6. 1.41% reduction in delay costs caused by unexpected utilities
7. 1.41% reduction in information gathering and verification cost
8. 1.04% reduction in restoration cost

It was concluded that SUE can provide accurate utility information with important project benefits at reasonable cost. A ratio of 1.65% was determined as the ratio of SUE cost to total project cost. The study also showed that the greater the complexity level of buried utilities, the higher the SUE benefits.

Region of Lombardy, Italy 2012

A pilot project was undertaken to map all underground infrastructure on the site of Expo Milano in preparation for the 2015 event in Milan. All underground infrastructure in the project area (230 000 square meters) including electric power, water, sewers, gas, district heating, street lighting, and telecommunication were mapped by combining historical records and IDS GeoRadar ground penetrating radar (GPR) technology. A key objective of the project was an economic analysis of the costs and benefits of applying GPR to detect the location of underground infrastructure. The analysis estimated that the return on investment is about €16 for every euro invested in improving the reliability of information about underground infrastructure. The analysis emphasized that there were other important, but non-quantifiable, benefits including better safety for both workers and the public as well as fewer traffic disruptions.

Pennsylvania Department of Transportation 2007

This study conducted by Penn State and sponsored by the Pennsylvania Department of Transportation PennDOT) and the U.S. DoT, Federal Highway Administration (FHWA) performed a benefit-cost analysis of 10 SUE highway projects from different PennDOT districts. The case studies were investigated by conducting interviews with utility engineers, SUE consultants, and project engineers. Site visits, analyses of project data, and detailed individual studies of the 10 SUE highway projects were also performed for this research. These projects were selected randomly from a list of projects that utilized SUE quality level A and/or B. The projects investigated in this study involved road construction and bridge replacement in urban, suburban, and rural areas. PennDOT project managers and engineers, utility owners, SUE consultants, designers, and contractors were interviewed. A savings of $22.21 for every $1.00 spent on SUE was estimated based on the analysis of the 10 projects. These projects had a total project cost (including both design and construction cost) in excess of $120 million. The costs of conducting SUE (to ASCE QL A or B) on these 10 projects were less than 0.6 percent of the total project costs. The benefit was cost savings of 15% over traditional approach relying on ASCE QL C and D utility data.

Project costs ranged from $2 million to $63 million. The quality of the utility records for these projects was poor or fair. The cost of conducting SUE ranged from $20,000 to $141,000 for these projects. The ratio of SUE cost to the total project cost ranged from 0.22% to 2.8%, with an average of 1.15%. SUE resulted in cost savings ranging from $65,000 to $4.5 million. The benefit-cost ratio ranged from 3.25 to 33.93, with an average of 22.21. In other words $22.21 can be saved for every $1 spent on SUE. The costs of conducting SUE on these 10 projects were less than 0.6 percent of the total project cost. Furthermore the analysis revealed a strong relationship between benefit of SUE and utility complexity. The benefit derived from performing a SUE survey increases as the underground utility complexity increases.

Ontario Sewer and Watermain Contractors Association 2004

In 2004 in Canada, the Ontario Sewer and Watermain Contractors Association commissioned the University of Toronto to investigate the practice of using SUE on large infrastructure projects in Ontario. Osman and El-Diraby (2005) analyzed nine SUE projects in Ontario, conducting interviews and project case studies. They identified 11 cost saving items from the 21 cost savings items used by 1999 U.S. DOT Purdue Study. The results of Ontario Study showed that the average return-on-investment (ROI) for SUE Osman and El-Diraby (2005) analyzed nine SUE projects in Ontario, conducting interviews and project case studies. They identified 11 cost saving items from the 21 cost savings items used by Purdue Study. The results of Ontario Study showed that the average return-on-investment (ROI) for SUE ranged from $1.98 to $6.59 with an average of $3.41 for each $1 spent.

U.S. DOT Federal Highway Administration 1999

In a study conducted by Purdue University Department of Building Construction Management for the U.S. DOT Federal Highway Administration, a total of seventy-one projects (71) from Virginia, North Carolina, Texas, and Ohio were studied. The total construction costs of these road projects were in excess of one billion dollars and involved interstate, arterial, and collector Roads in urban, suburban, and rural settings. DOT project managers, utility owners, constructors, and designers were interviewed.

Based on Interviews and surveys of DOTs, utility owners, SUE consultants, and contractors 21 categories of cost savings were defined to quantify the savings in terms of time, cost, and risk management. The 21 categories of cost savings identified in the study were as follows: reduction in unforeseen utility conflicts and relocations; reduction in project delays due to utility relocates; reduction in claims and change orders; reduction in delays due to utility cuts; reduction in project contingency fees; lower project bids; reduction in costs caused by conflict redesign; reduction in the cost of project design; reduction in travel delays during construction to the motoring public; improvement in contractor productivity and quality; reduction in utility companies' cost to repair damaged facilities; minimization of utility customers' loss of service; minimization of damage to existing pavements; minimization of traffic disruption, increasing DOT public credibility; improvement in working relationships between DOT and utilities; increased efficiency of surveying activities by elimination of duplicate surveys; facilitation of electronic mapping accuracy; minimization of the chance of environmental damage; inducement of savings in risk management and insurance; introduction of the concept of a comprehensive SUE process; and reduction in right-of-way acquisition costs.

The reduction in risk for all of these potential benefits by conducting a SUE survey has been difficult to quantify. Benefits have been categorized as exact costs that can be quantified in a precise manner, for example the cost of potholing or the cost to eliminate utility conflicts; estimated costs that are difficult to quantify, but can be calculated by studying projects in detail, interviewing the personnel involved in the project, and applying historical cost data; qualitative costs that cannot be estimated due to a lack of data, for example, for example, avoided impacts on nearby homes and businesses.

The analysis revealed savings ranging from $0.34 to $206.67 for every dollar invested in SUE with an average of $4.62. The cost of conducting SUE surveys on these projects was less than 0.5 percent of the total construction costs. SUE surveys resulted in a construction savings of 1.9 percent over the traditional approach to underground utilities that relied on ASCE QL C and D. Using this ratio and a national expenditure in 1998 of $51 billion for highway construction (FHWA), requiring SUE on road projects could result in a minimum national savings of approximately $1 billion per year.

The qualitative savings were non-measurable, but it is clear that those savings are also significant and may be many times more valuable than the quantifiable savings. The study concluded that SUE is a viable, cost effective practice that reduced the risks associated with existing subsurface utilities resulted in significant quantifiable and qualitative benefits.

2004 American Society of Civil Engineers

A subsequent reanalysis of the data from the 1999 USDOT Purdue Study found that the estimated benefit of conducting a SUE survey was a cost savings of $12.23 for every $1 spent on SUE. The largest contributors to the cost savings derived from SUE were as follows:

1. 37.1% reduced number of utility relocations
2. 19.3% reduced claims and change orders
3. 11.6% reduced accidents and injuries
4. 9.6% reduced project delays
5. 3.5% reduced right-of-way acquisition costs
6. 3.3% savings in risk management and insurance
7. 15.5% other

The analysis concluded that the average ratio of the cost of SUE to total project cost ranged from 0.02% to 10.76% with an average of 1.39%.

Conclusion

These ROI studies show that SUE can provide accurate utility information with important project benefits at a reasonable cost. While SUE surveys have been shown to reduce the risk of budget overruns and project delays for construction projects, by themselves they are not a silver bullet for reducing the number of incidents of underground utility damage. As Heathrow International Airport and Japan have shown a comprehensive program involving policies, regulations, and construction practices is required.

ROI of $11.39 for every $1 spent on subsurface utility engineering on highway construction projects

A definitive study of twenty-two projects utilizing subsurface utility engineering (SUE) and eight non-SUE projects from Pennsylvania Department of Transportation (PennDOT) districts has revealed that $11.39 can be saved for every $1 spent on SUE.  The cost of conducting a SUE survey was estimated at 1.65% of total project cost.

Eleven main benefit factors were considered in the analysis.

1. Utility relocation cost
2. Utility damage cost
3. Emergency restoration cost
4. Traffic delay cost
5. Business impact cost
6. User service cost
7. Environmental impact cost
8. Information gathering and verification cost
9. Legal and litigation cost
10. Efficient utility design and construction
11. Other utility related costs and benefits

On the cost side two kinds of costs are involved in conducting a SUE survey. One is the use of geophysical techniques such as EMI and GPR to identify the location of underground utilities and other objects.  The other is potholing (using safe excavation techniques) to confirm the location of the utilities and objects identified.  In this study for the projects utilizing SUE, costs are obtained from directly from project accounting. For the projects that did not use SUE, costs are estimated from interviews, historical data, and individual project studies.

For the twenty-two projects where SUE was applied, all underground utilities and other objects were located to ASCE 38-02 quality level A (potholing) or B (EMI and GPR).  For the eight projects utilized traditional methods, the location of underground networks was estimated to ASCE quality levels C (site visit) and D (as-builts).

Previous ROI studies of SUE only used projects where SUE surveys were performed to quantify the cost savings of SUE.  In this study, non-SUE projects were used to determine the cost savings of SUE because direct costs incurred by problems that would have been avoided by SUE can be considered as SUE benefits. The results of the study revealed that $11.39 can be saved for every $1 spent on SUE on road projects. A ratio of 1.65% was determined as the ratio of SUE cost to total project cost. It was concluded that SUE can provide accurate utility information with important project benefits at reasonable cost. Project relocation cost is the most important item to the cost savings, representing 40.33% of total savings. The study also showed that the greater the complexity level of buried utilities, the higher the SUE benefits.

Source

Yeun J. Jung, Evaluation of subsurface utility engineering for highway projects: Benefit–cost analysis, pages 111-122 in Tunnelling and Underground Space Technology Volume 27, Issue 1 Pages 1-168 (January 2012)

Elements for improving underground utility mapping to reduce risk of damage during construction

Without accurate maps of underground infrastructure, every construction project has the potential to become a disaster site. Unlike the aviation industry where reliable data is collected and is accessible to investigators to prevent disasters from happening in the future, there is limited access to data about the location of underground infrastructure and what data is accessible is inaccurate, out-of-date and incomplete with the result that serious incidents during construction with injuries and fatalities occur again and again.  It is estimated that in the United States $10 billion is devoted to locating underground infrastructure prior to and during construction, but the available statistics indicate that this is not reducing the number or severity of incidents of underground utility damage.  Furthermore inaccurate and missing information about underground infrastructure increases the risk of schedule and budget overruns.  It has been estimated that this represents a $50 billion drag on the U.S. economy and upto a £6 billion drag on the U.K. economy.

Nearly every month the news carries reports of explosions caused by damage to underground utilities during construction excavation. In the last few months of this year there have been explosions in Murrieta, California (July) where a utility worker was killed and 15 others injured, downtown San Francisco (February), Durham, North Carolina (May), and I could go on. These incidents are more frequent than many people realize. 

This is not an impossible problem. A number of cities, regions and countries around the world have recognized the importance of accurate information about the location of underground infrastructure and implemented processes to reduce the risk of these events. For example, comparing the United States and Japan reveals a startling difference in the number of incidents of underground utility damage during construction. The number of incidents in the U.S. is between 400,000 and 800,000 per year (roughly one or two every minute). For all of Japan the number of incidents in 2016 was 134. Clearly something can be done to reduce the risk for construction workers and the public.

Over the years I have personally compiled information on 25 jurisdictions including airports in the Americas, Europe, and Asia Pacific that have implemented various policies and organizational structures for sharing information about the location of underground infrastructure. These range from government mandated and implemented, government mandated and privately implemented, voluntary industry associations, and private companies. In this article I provide a synthesis of measures most of which have been implemented, are being implemented, or have undergone pilot implementations. These can be grouped in several broad categories.

• Reliable statistics on underground utility damage

• Policies, procedures, and technologies for raising the level of accuracy, timeliness and completeness of information about the location of underground infrastructure.

• Digitalizing the capture, sharing and updating of location information about underground infrastructure.

• Ensuring security and privacy of location information about underground networks including protection for competitive information. 

• Providing access to stakeholders to underground infrastructure location information throughout the construction project life-cycle from planning and design through construction to operations and maintenance.

• Liability model for sharing responsibility for costs of underground utility damage.

Airports, university campuses, and industrial campuses are characterized by a greater density of underground utilities and by more types of underground equipment( communications cables, aeronautical ground lighting cables, gas mains, low voltage electric power cables, high voltage electric power cables, storm water mains, sanitary waste water mains, potable water mains, grey water mains, fuel mains, fire fighting water mains, and a variety of underground structures.) Underground infrastructure in airports, university and industrial campuses typically has a single owner though not always.

Public jurisdictions such as national, regional, state or provincial and municipal governments are responsible for the public right of way.  Typically underground infrastructure in the public right of way involves multiple private owners; telecom network operators, electric power utilities, gas network operators, water and wastewater operators,and others such as heating and fuel transmission pipeline operators. Dealing with multiple private owners who attempt to maintain information about their network facilities typically in a GIS considerably complicates the process of acquiring and maintaining accurate location information about underground cables and pipes.

1. Reliable statistics are essential to determine the social impact of underground utility damage and to assess the effectiveness of policies, procedures and technologies designed to reduce the number and severity of incidents of underground utility damage. Every incident of damage to underground infrastructure should be reported including injuries, fatalities and direct cost. Indirect cost is a nice to have, but very difficult to estimate. Cause is difficult to determine because it depends on who is reporting the incident - network operator, the excavator, or by an independent organization.  A network operator's perspective may be that the contractor did not exercise care during excavation, whereas the contractor's perspective may be that the location of the cable or pipe as identified as a result of a one-call request was inaccurate.  Responsibility for submitting this information has to be assigned to the   One option for doing this efficiently is to classify incidents by seriousness and assign different levels of reporting based on this classification. For pipelines PHMSA assigns levels of seriousness based on cost, consequence, injuries and fatalities.  Significant incidents include any of the following: (1) Fatality or injury requiring in-patient hospitalization, (2) $50,000 or more in total costs,(3) release of significant volumes of gas or hazardous liquid. Serious incidents include a fatality or injury requiring in-patient hospitalization.  In civil aviation each serious incident is investigated by the NTSB, an impartial group of experts who determine technical cause but do not assign blame. The available evidence from the U.S. civil aviation industry, pipeline industry, and many national statistical agencies suggest incident reporting should be mandated to ensure statistically reliable data.  This entails significant penalties for not reporting incidents. Ex. Pipeline and Hazardous Materials Safety Administration (PHMSA), Heathrow International Airport, Japan Construction Industry Association

2. 3D mapping of underground infrastructure prior to planning and design. Making the location of underground infrastructure available to engineers so that designers have access to not only accurate above-ground survey but also accurate below-ground location information enables engineers to avoid underground infrastructure during design. 3D maps of underground utilities also contributes to reducing unnecessary and costly utility relocation. Below-ground location information should be at least ASCE quality level B.  The entire area should be should be assessed by an SUE engineer in collaboration with utilities and telecoms with equipment in the area. The assessment may include scanning with modern remote-detection tools (EMI, GPR and inertial locating ) to raise the quality of location of all underground facilities to QL B and to identify abandoned or unknown infrastructure.  The cost of raising the quality level of facilities in the design area to B could be assigned to the relevant network operator, engineering firm or shared. For unknown and abandoned equipment an attempt should be made to find the original owner. Ex. Colorado 811

3. Locating unknown and abandoned facilities.  The current one-call system is targeted toward utilities locating their own facilities, typically based on their as-builts.  But there is no formal mechanism for locating facilities that have been abandoned or are not shown on network operator as-builts.  Requiring a full SUE survey in addition to a traditional surface survey at part of planning and design at the beginning of a construction project helps avoid surprises during construction. Ex. Colorado 811
   

4. Capturing and sharing the location of infrastructure detected as a result of a SUE survey at the beginning of a project or as the result of an information request to one-call/811.  Currently utilities are required to paint the ground and in some jurisdictions to provide a paper sketch indicating the location of underground utilities.   This information needs to be captured digitally and shared.  The objective is over time to build up a high quality (QL A and B) database of the location of underground infrastructure that can be shared.  Ex. Colorado Department of Transportation

5. Capturing and sharing the location of infrastructure exposed during construction. In the United States it is estimated that $10 billion is spent annually to locate underground infrastructure prior to and during construction.  Much of this information is not shared and the next time excavation occurs in the same area, the underground infrastructure must be located again.  If this information is captured and shared, over time a high quality (QL A and B) database of the location of underground infrastructure will be formed that will avoid locating the same infrastructure over and over again.  Alternatives for recording the location of exposed infrastructure include total station, RTK, and LiDAR, which tend to be expensive but high quality (QL A). Other alternatives are consumer photography with control points or structures with accurately known locations.  It is essential that this does not increase excavation costs for the contractor.  Contractor margins are tight and having to keep a survey crew on hand during excavation would significantly increase costs. There have been experiments by the City of Chicago, Bentley and Costain aimed at efficiently capturing location information about utilities exposed during construction.

6. An efficient process to update the information recorded in network operators' databases. Information captured as part of a SUE survey, as a result of an information request to one-call/811, or detected during excavation may differ from the records contained in network operators' databases.  For continuous improvement of the quality of the information about the location of network facilities requires an efficient way to compare and update this information.

7. Reducing or eliminating the update backlog.  Utilities regularly maintain underground infrastructure, move it as part of a construction project, or abandon it.  This information has to be reported back to the network operator to update the information in the utility GIS.  There are two dimensions to updates; the accuracy of the location information provided from the field and the update backlog, the time it takes for updates to be entered in the utility GIS.  As with the as-built backlog this backlog can stretch into months.  The objective should be better than a day. This issue can also be resolved by regulation or by a suitable liability model. Ex. Ofgem in the U.K. requires backlogs to not exceed 42 calendar days.

8. Improving the accuracy of location information for new underground infrastructure.  If all new facilities are located to survey quality, over time location accuracy will continue to improve  as older facilities are retired. Alternatives for recording the location of newly installed infrastructure include total station, RTK, LiDAR, and photogrammetry with control points or structures with accurately known locations.  Whatever the technology the result should be ASCE quality level A.  Special provision must be made for capturing the location of facilities installed using horizontal (trenchless) drilling, for example, inertial mapping of pipe networks.  Since reliable as-builts are generally a network operator responsibility - policies are required to ensure that as-builts for newly installed equipment are accurate. There are several ways to do this; legislation which enables a government or regulator to conduct QA/QC checks on submitted as-builts or a shared liability model that assigns some responsibility for subsurface utility damage to network operators whose as-builts are inaccurate or out-of-date. A  liability model would assign liability of any underground damage during subsequent excavation to the network operator if the as-built location information is incorrect. Ex. City of Calgary, Singapore

9. Reducing or eliminating the as-built backlog.  If the time it takes for as-built information to enter the utility GIS or other database from the time new infrastructure is installed is measured in months or longer, the utility GIS is not sufficently reliable for locating underground infrastructure for construction purposes.  The objective should be better than a day. This can be resolved by regulation or by a suitable liability model.  Ex. Ofgem in the U.K. requires as-built backlogs to be less than 42 calendar days.

10. Assigning a quality level based on a generally accepted quality standard to every piece of underground infrastructure. This is critical for determining the type of excavation equipment that it is appropriate to use. It can also provide the basis for a shared liability model.  Ex. ASCE 38-02 in the U.S., CSA S250 in Canada, PAS 128 in the U.K., France DICT

11. Digitalizing the capture and sharing of information about the underground.  In North America, most one-call legislation only requires marking the ground prior to the initiation of construction.  In Ontario a written record is required in addition to marking the ground. At the federal level in Canada there is legislation initiated in the Senate and that offers the alternative of the exchange of only a written record of the location of utilities mapped prior to excavation - no visit to the site to mark the ground is required. This would open the door to exchanging a digital record of the location of utilities found prior to excavation which would be much more efficient because it could obviate the need to visit the site of the proposed excavation.  However, it would also a higher quality standard for the location of underground infrastructure than is currently the practice.  Ex. ROADIC (Japan), KLIP in Flanders, KLIC in the Netherlands

12. Digitalizing the flow of information about underground infrastructure requires a generally recognized standard for sharing information about the subsurface. The Open Geospatial Consortium (OGC) is developing an underground information exchange standard, with the appropriate acronym MUDDI, that is intended to provide an open standards-based way to share information about the below ground. There are a number of data models for different types of underground infrastructure and geotechnics. MUDDI builds on and augments existing standards to create a unified model supporting multiple use cases. The MUDDI model is intended to support routine street excavations, emergency response, utility maintenance programs, large scale construction projects, disaster planning and response, and smart cities programs. For street excavations the requirement is location of all entities with high horizontal, medium vertical accuracy (2.5D) of underground infrastructure; for large construction projects, detailed 3D geometry of underground infrastructure and detailed 3D geotechnics; for emergency response, interdependencies between different networks; for utility maintenance, network topology and facility location and condition; and for smart cities the ability to monitor and relate streams of data from sensors. This has not yet been adopted by a jurisdiction, but agencies in the U.K. (Ordnance Surevy), Singapore (Singapore Land Authority), and New York (Fund for the City of New York) are actively supporting the development of the standard.

13. Efficient information flow.  Requiring vans with locating crews from several network operators to visit the site of a proposed excavation just prior to construction to scan the ground for their facilities using EMI and GPR and mark the ground is inefficient. An on-line system that allows an engineer or contractor to go online and define a polygon enclosing the proposed excavation and then within less than a day providing access to maps of underground infrastructure in the area can save network operators time and money.  However, the effectiveness of this solution is highly dependent on the quality of the location information maintained by network operators.  In North America the current one-call system requires that underground facilities be mapped to ASCE QL B before starting construction.  An online system providing digital maps composed of utility operators' as-builts would lower the accuracy of the location information provided to contractors and in the absence of other measures would likely increase underground utility damage. Ex, KLIP in Flanders, KLIC in the Netherlands.

14. Rules for the appropriate type of excavation equipment.  Rules are required that restrict the type of excavation equipment based on the quality level of underground utilities identified by network operators.  For example if facilities have been assigned ASCE quality level C or D, only hydraulic, vacuum or hand excavation may be used.  Ex. Heathrow airport

15. Security, privacy and protecting competitive information. To enable this information to be useful in reducing the risk of underground infrastructure damage during construction it has to be shared in a secure way which respects privacy.  In particular it must protect competitive information. There are a number of organizational ways of doing this; government can mandate, implement and run the system, government can mandate but leave it to the private sector to implement and run, an industry consortium with or without government mandate can implement and run the system, regulations could require sharing this information but leave it to the private sector to implement and run, or a private company could take overall responsibility.  Around the world there are examples where each of these alternatives can be found.  The information should be available to engineers during the planning and design phases of construction projects, to contractors for use during excavation, and to organizations responsible for operating and maintaining highways and other civil structures.  Other potential use cases for this data include disaster planning and emergency response.  Ex. KLIP in Flanders and KLIC in the Netherlands, North East Underground Infrastructure Hub (NEUIH) in Newcastle, England

16. Liability model for sharing responsibility for costs of underground utility damage.  The advantage of a rule-based shared liability model that assigns varying levels of responsibility to both contractors and network operators is that it provides motivation to network operators to improve the quality of their location information about their underground infrastructure existing and new.  An example of a shared model is the following: if a network operator identifies the location of a piece of underground equipment as Quality Level A according to the ASCE 38-2 standard and an excavator hits it, the excavator would be liable for costs if the facility was where the network operator said it was, or the network operator would be liable if it wasn't.  For an excavator intending to dig in an area where there is underground infrastructure assigned to level C or D, the cost to bring all infrastructure to quality level B would lie with the network operator (as it does now with North American one-call systems). If the network operator declines to do this, the liability for any underground damage would lie with the network operator. Ex. France DICT

These measures not only can reduce the risk of underground utility damage and the associated risk to the public during construction and thereby lower insurance costs, but can also significantly reduce the cost of infrastructure construction, for example, by avoiding major utilities and reducing the unnecessary and costly moving of utilities on civil engineering projects.

Experience has shown that over time these elements can result in increasingly accurate digital representations showing the location of underground infrastructure that is available to stakeholders in construction projects including planners, engineers, contractors and facilities managers, for utility maintenance, and potentially for other use cases such as utility outage management, disaster planning, emergency response and smart city programs.

Mapping underground utilities required for public civil engineering projects in Colorado

Colorado's statutes for the prevention of damage to underground utilities were assessed by the federal pipeline authority PHMSA in 2014 and found to be below standard in two areas. As a result the Colorado General Assembly has revised its excavation safety statutes (Article 1.5 of Title 9) to be compliant with current best practices. The latest legislation is progressive. Most importantly, it explicitly mandates subsurface utility engineering (SUE) practice during engineering design on public construction projects to determine the location of all underground utilities in the proposed excavation area to ASCE 38-02 quality level B by a licensed professional engineer. (ASCE quality level B requires the application of subsurface remote sensing detection technologies such as electromagnetic detection and/or ground penetrating radar.) Furthermore, the legislation creates an enforcement agency for reviewing violations of Article 1.5 with the power to impose civil penalties.

Background

According to the FHWA underground utilities are a major cause of highway construction schedule and budget overruns. In the traditional approach to highway construction, the design engineer ignored utilities during design. Just prior to the commencement of construction the state one-call centre would be contacted and the utilities and telecoms with underground facilities in the area of the proposed excavation would visit the site and mark the ground with paint or flags.  Utilities that conflicted with the design would then be relocated. As a result utilities are routinely relocated, often at great expense and often unnecessarily. An alternative approach is to design the highway knowing in advance the location of below-ground utilities. I have blogged about two recent highway construction projects, Birmingham AL and Cedar Falls IA that took this approach with substantive benefits. The challenge is that accurate data about the location of underground utilities is generally lacking.  It is well-known that there is a consensus among DoTs that accurate and comprehensive utility location data helps make better decisions and reduces the risk of unforeseen problems with utilities emerging during the construction phase.

In addition to construction delays, damage to underground utilities during construction makes every construction project a potential disaster site.  In order to promote improved safety PHMSA has developed a uniform tool that it uses for assessing state one-call systems. In 2014 PHMSA found that the Colorado one-call system had serious deficiencies. The first was that some organizations in the state were exempt from calling the one-call centre prior to excavation. Even more seriously it found that the legislation did not assign an agency to enforce the legislation.

In 2017 there was an explosion at a home in Firestone, Colorado that resulted in two deaths and a serious injury. The subsequent NTSB report concluded that as a result of local authorities allowing the development of land adjacent to oil and gas production fields without complete documentation from the operator on the location and status of its gathering system pipelines, a 1" pipeline that was still carrying natural gas was the cause of the explosion.

In 2018 the Colorado legislature revised its one-call legislation. The latest legislation is progressive, chiefly for four reasons.

1. It explicitly mandates subsurface utility engineering (SUE) during engineering design for public civil engineering projects to determine the 2D location of underground utilities to ASCE 38 quality level B by a licensed professional engineer. (ASCE quality level B requires the application of remote sensing detection technologies such as electromagnetic detection and ground penetrating radar.)
2. Prior to the commencement of construction in addition to painting or flagging a proposed excavation site, infrastructure owner/operators are required to provide a digital sketch, a hand-drawn sketch, or a photograph.
3. It may put some degree of onus on owner/operators to provide accurate information about the location of their underground facilities.
4. It creates an enforcement agency for reviewing violations of Article 1.5 with the power to impose civil penalties.

Subsurface utility engineering-required projects

In many states there is no provision as part of one-call legislation for owner/operators to provide information about underground utilities to engineers to assist with the design of civil engineering projects. This often results in the wasteful relocation of utilities. In Colorado it is now mandatory on public civil engineering projects to create a 2D map of underground utilities as part of design. Subsurface utility engineering-required projects are public projects that primarily involve horizontal construction, an excavation footprint exceeding 1,000 square feet and two feet in depth and that require the design services of a licensed professional engineer. During the design phase of these projects a licensed professional engineer is required to attempt to determine the location of all underground utilities within the proposed excavation area to ASCE 38-02 quality standard B or better. To assist this process utility owner/operators are required to either provide their available records of the approximate 2D location of their underground facilities or mark the ground in the excavation area .

Digital or paper "sketches" now required

In most states one-call legislation only requires painting or otherwise marking the ground to show the location of underground utilities. In Colorado now in addition to marking the ground owner/operators are required to provide documentation listing the owner/operator's name, the size and type of each marked underground facility, and a digital sketch, a hand-drawn sketch, or a photograph that includes a readily identifiable landmark. This is a first step toward being able to simply provide an accurate digital map of underground facilities in the proposed excavation area (as is done in the Netherlands and Flanders).

Owner/operator's responsibility for accuracy

North America, United Kingdom, Australia and other jurisdictions are characterized by a liability model that puts the onus on excavators to avoid hitting underground utilities. This provides little motivation for owners/operators to improve the quality of their information about the location of underground facilities. In Colorado Article 1.5 appears to alter this general liability model. It states that if the documentation or markings are determined to be inaccurate, the excavator shall immediately notify the owner/operator through Colorado 811 to request an immediate reverification of the location of underground facility by the owner/operator. The owner/operator is required to respond as quickly as practicable during which time the excavator can continue excavation activity with appropriate caution. Furthermore, Article 1.5 states that if the documentation or markings provided still fail to identify the location of the underground facilities, the excavator is required to notify Colorado 811, but can then proceed with excavation. Article 1.5 states that in this case the excavator is not liable for damage to the owner/operator's facilities except upon proof of the excavator's lack of reasonable care. However, accuracy is not quantified. Later in Article 1.5 where liabilities are discussed, the language relating to accuracy seems less strong. It states that excavators are liable if they fail to notify Colorado 811 of their intention to excavate or fail to exercise reasonable care in excavating. Owner/operators are liable if an underground facility is damaged as a result of the owner/operator's failure to participate in Colorado 811 or by their failure to use "reasonable care" in the marking of the damaged underground facility.

Enforcement

The most important area that PHMSA found deficient in the earlier Colorado damage prevention legislation was that it did not provide for enforcement. The most recent legislation provides for the creation of an Underground Damage Prevention Safety Commission in the Department of Labor and Employment that is independent of Colorado 811. The commission operates independently of Colorado One-call and is composed of six representative representing owner/operators, four representing engineers, contractors and excavators, four representing government agencies and one representing farmers and ranchers. It has two primary responsibilities, Firstly, to advise Colorado state agencies, the general assembly, and local governments on polices and best practices. Its other responsibility is enforcement. It is responsible for reviewing alleged violations of Article 1.5 and can order appropriate remedial action or penalties. Alleged violations are reviewed by a committee convened by the Safety Commission which must include the same number of members representing excavators and owners/operators plus one from another group. A recommendation of remedial action that includes a fine requires a unanimous vote of the review committee. Alternatively a voluntary alternative dispute resolution program is available through Colorado 811 to all owners/operators, excavators, and others regarding disputes arising from damage to underground facilities.

The legislation requires the reporting of damage to underground utilities by members (owner/operators). For each incident the location, duration of service interruption and whether Colorado 811 had been notified prior to excavation must be reported to Colorado 811. However, this is much less information than what is requested by the Common Ground Alliance's voluntary reporting of underground utility damage or PHMSA's mandatory reporting of pipeline incidents. Specifically it does not include fatalities, injuries or costs.

Summary

Taken together these modifications to Colorado's one-call legislation are progressive, especially by requiring mapping of underground utilities during engineering design for public civil engineering projects such as highway construction. Its implications for liabilities is less clear.  Shared liabilities would provide an important motivation for utility and telecom owners/operators to improve the quality of their information about the location of underground facilities.  That a digital or paper sketche or imagery is now required in addition to marking the ground would appear to be step in the direction of a completely digital 811 system such as KLIC in the Netherlands or KLIP in Flanders.