ListenChanging the Subsurface Utility Mapping Industry with Michael Twohig of DGT Associates
Enhanced Scanning owner Forrest Sim interviews Michael Twohig, a subsurface utility mapping expert at DGT Associates.
Executive Summary
- Core Theme: The intersection of professional nomenclature, varying state regulatory frameworks, the fallacy of “accidental” utility strikes, and the life-saving value of mentorship and industry safety advocacy.
- The SUE vs. SUM Debate: While the mainstream industry standard is SUE (Subsurface Utility Engineering), Mike prefers the term SUM (Subsurface Utility Mapping) or SUI (Investigation). He notes that because his deliverables are strictly digital map files and remote sensing data, they do not actually perform engineering work.
- The “Naughty” Verbiage Trap: Forrest highlights that in California, using the word “mapping” can run non-surveyors afoul of state boards, as legally only licensed land surveyors can create a “map.” Mike agrees that terms and definitions vary wildly across state lines. To safely scale across state boundaries, large firms must either cross-license their staff or strategically team with local licensed firms.
- The Fallacy of “Accidental” Utility Strikes: Mike fiercely rejects the word “accident” when a contractor strikes a fiber, gas, or power line. He defines these incidents as outright failures of due diligence. While OSHA regulations require contractors to perform pipe-locating investigations alongside calling 811, many laggards treat it as a box-checking chore. Mike stresses that utility investigations are just as critical as geotechnical or environmental surveys, citing a California 405 highway project that incurred a $550 million claim largely due to unexpected utility delay discoveries.
- The Need for Legislative Mandates: Mike does not believe the construction industry will ever self-regulate or voluntarily adopt best safety practices to protect underground assets. He insists that real cultural change only happens via strict state legislation, praising states like Colorado, Pennsylvania, and Minnesota for passing laws that mandate subsurface utility mapping during the design phase.
- The Origins of “Ugg Monday”: Mike is well-known on LinkedIn for posting striking historical black-and-white archival photographs of extreme subsurface working conditions. He explains that these photos are the byproduct of his firm’s strict policy of “doing their homework”—digging through historical, digital city archives to look at brownfield histories, contaminants, and old gas tanks before sending a crew to a site.
- A Definitive Lesson in Trench Safety: Mike recounts a formative memory from his rookie days in 1985 on an infrastructure pipeline project. After an older superintendent refused to spend time or money on a trenching box for a 5-foot deep trench, the walls collapsed, burying four workers. Mike had to physically dig them out—including the stubborn superintendent.
- Networking and Ongoing Evolution: Long before LinkedIn existed, Mike built his massive professional network organically by attending industry trade shows like the Excavation Safety Conference. Despite being a “40-year rookie” with experience across multiple continents, Mike maintains that true professionals must remain open to collaboration over competition, as there is always something new to learn from other firms.
About Enhanced Scanning
Enhanced Scanning helps customers identify hazards that are hidden from view by providing professional subsurface locating services for the construction, engineering, and scientific communities. The company is committed to improving locating practices through advanced technology and extensive technician training. Owner Forrest Sim is an established industry professional who regularly travels throughout the country to speak at industry events, where he shares his knowledge of utility locating, concrete scanning, and other subsurface investigation techniques.
Enhanced Scanning’s approach combines experienced technicians with a broad selection of non-destructive locating tools. These include ground penetrating radar (GPR), electromagnetic (EM) and electromagnetic induction (EMI) locators, magnetometers, push cameras, and pulse wave generators. Having access to multiple technologies allows technicians to choose the methods that are best suited to the specific conditions of a project. It also allows them to gather information from different sources rather than relying on a single locating method.
Depending on the application, Enhanced Scanning can use these tools to locate buried utility lines, identify post-tensioned cables and other features inside concrete slabs, and recognize changes in soil structure. The resulting information gives customers a much clearer picture of the conditions they may encounter once work begins. With that knowledge, contractors and other professionals can plan accordingly, address potential hazards, and move forward with greater confidence in the safety of their project.
