62 Colorado Public Works Journal ACEC ENGINEERING FORWARD ASCE38 Subsurface Utility Engineering – Part I On May 25, 2018, Governor John Hickenlooper signed Senate Bill 18-167 – concerning increased enforcement of requirements related to the location of underground facilities into law. The intent of this law is to improve and protect the health, safety, and welfare of the public by accomplishing three key changes to existing policy: 1) Eliminate tier two membership of utility companies in Colorado 811 and estab- lish a true One Call system. 2) Establish a Safety Committee to enforce the law universally and fairly. 3) To improve the quality of utility data on construction plans by requiring the use of ASCE 38 during design. All public owners must adopt the standard as of August 8, 2018 for projects that require a Professional Engineer for the design and have a construction excavation footprint over 2-inches in depth and over 1000 contiguous square feet in area. ASCE 38 is the “Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data” as produced by the American Society of Civil Engineers in 2002. This standard breaks down the quality of utility data into four quality levels: “A”, “B”, “C”, and “D” with “A” being the least uncertain and “D” being the most uncertain as quality of depiction is concerned. Quality Level “D” data is based on records, oral recollection, historical data, or one-call marks and involves no field investigation using geophysics or survey equipment. Quality Level “C” data is based on the survey of surface utility appurtenances tied to project survey control that is correlated with Quality Level “D” information on the utility segment. Quality Level “B” data involves the use of a suite of surface geophysical equipment including but not limited to: electro- magnetics, ground penetrating radar, elastic wave, and mag- netic gradiometers to designate the approximate horizontal position of the utility which is then surveyed using project control and correlated with Quality Level “C” and “D” data to resolve any discrepancies. Andrew Sylvest Quality Level “A” data is provided by performing non-destruc- tive vacuum excavation to expose a utility at a precise point. The utility is then measured, photographed, and surveyed using project control to a vertical accuracy of 0.05’. Owners will be required by the new law to use professionally licensed consultants rather than “utility locating and potholing contractors” and will in turn receive a professional product that is backed by professional liability insurance and suitable for design rather than questionable data that is disclaimed leading to the liability subsequently being passed on to the contractor resulting in higher bids. By performing Quality Level “B” designating concurrent with the topographic survey, the designer will have a surface base map and a subsurface utility base map suitable for design. By performing Quality Level “A” test holes only at conflict points identified later during design, we will eliminate exces- sive excavations which will reduce costs and disturbances to the pavement on our roads. Later this summer, ACEC Colorado with CDOT will hold state-wide trainings to help engineers and owners in implementing the law. The author Andrew Sylvest is Utility Engineering Manager at SAM Companies.