Case Studies
- On a major highway project in Richmond, the Virginia DOT's consultant dug 156 test holes at locations where it was thought highway utility conflicts were possible. Using the data obtained, VDOT's roadway and hydraulics designers determined that conflicts would occur at 75 of the sites. As a result, design changes were made and 61 of the potential conflicts were eliminated. By making these changes, $731,425 worth of utility adjustments were avoided; whereas, the cost of digging the test holes was only $93,553, resulting in a savings of $637,872.
- The Virginia DOT credits SUE with helping to reduce the time needed to design highways from 5 years to 4 years, a 20% reduction in time.
- On a utility project in Columbus, Ohio, the Columbus Southern Power Company designed and installed almost 2 km of underground 138 kV electric line through the downtown area at lower cost, reduced risk, and ahead of schedule by including SUE in its design. The increased quality of the utility information presented at the prebid meeting increased the bidder's confidence in the construction plans, resulting in a bid which was $400,000 less than anticipated. The cost of SUE was less than $100,000. Additionally, there were no change orders as a result of utilities not correctly depicted on the plans, no utility relocations, no utility damages on the project, and no contractor claims.
- On a highway project in Maryland involving realignment and widening from 2 to 6 lanes, the use of SUE enabled the Maryland State Highway Administration (MSHA) to redesign the hydraulics system to minimize conflicts with utilities. Instead of impacting about 5,000 feet of each utility (gas, water, and sanitary), conflicts were reduced to about 400 feet of each. The cost for SUE was $56,000. Cost savings to MSHA and the utilities amounted to $1,340,000.
- On another project in Maryland, involving widening an Interstate highway from 4 to 6 lanes with full shoulders, retaining walls, and barriers, the use of SUE enabled MSHA to redesign the barriers and change the grading and ditches to minimize conflicts with utilities (gas, water, and telephone). The cost for SUE was $5,000. Cost savings to MSHA and the utilities amounted to $300,000, and the relocation time was reduced by 4-6 months.
- SUE was used on a highway project in North Carolina to locate a PVC water line along 18 miles of NC 168 in Currituck County. Location of the line was critical to determine conflicts with proposed pavement widening and shoulder excavation work. Using vacuum excavation, 40 holes were dug at a cost of less than $10,000. Using the resulting Quality Level "A" information, it was determined that approximately 21,280 feet of the water line could remain in place. This saved NCDOT an estimated $500,000.
- On another project in North Carolina, SUE was used early in the development of a project on the Southwest Loop Extension in Lenoir to identify utilities that needed to be relocated. Its use resulted in 16 storm drain boxes being changed to eliminate utility conflicts and in the assurance that 9 other storm drain boxes would not conflict with existing utilities. It was also used to accurately locate underground storage tanks.
- Florida DOT analyzed the use of SUE on major projects in Tallahassee and Miami and found that it saved $3 in contractor construction delay claims for every $1 spent for subsurface utility engineering.
- Fairfax County in Virginia started using SUE in 1980 in an effort to reduce construction expenses caused by unexpected utility hits, redesign costs, and contractor claims. Utilizing SUE during the design of projects has dramatically reduced the extent of the problems.