September 2017 Vol. 25, No. 3

Current Issue | Previous Issues | Subscribe | Download

Minnesota LTAP Exchange banner

Inspection vehicle improves culvert repair

man holding inspection vehicle

Photo: MnDOT

Culverts and pipes must be inspected regularly to determine if they need to be repaired or replaced, but culvert accesses are often too small for inspectors to enter. To meet this inspection need, MnDOT District 6 developed the Hydraulic Inspection Vehicle Explorer (HIVE), a radio-controlled car that takes lights and a camera into culverts and transmits inspection data wirelessly to a tablet. Each vehicle costs roughly $1,500.

The HIVE has been used to inspect hundreds of pipes and is already saving money. One visual inspection of a culvert showed damage to the ends of a pipe that typically would result in a full replacement cost of about $45,000. However, HIVE video footage from within the pipe showed the damage was limited to just 12 feet near the end. Instead of replacing the entire pipe, MnDOT workers fixed the problem for $1,000, resulting in a $44,000 savings.

  • Waterproof
  • Wi-fi transmission
  • 4x4 drive
  • $1,200 vehicle/camera
  • $300 tablet
  • Transported in 11”x17” box
  • Observed range
    • 24-inch diameter =~ 250 feet
    • 18-inch diameter =~ 150 feet
    • 12-inch diameter =~ 50 feet

The HIVE is a radio-operated car modified by Rochester MnDOT workers who are experienced radio-operated car hobbyists. The innovative vehicle received the 2016 Governor’s Better Government Award and was chosen as one of the nation’s top research projects in 2017 by the Research Advisory Committee of the American Association of State Highway and Transportation Officials.

“The HIVE has proven to be an invaluable tool for the inspection of culverts and pipes in southeast Minnesota,” says Jeff Vlaminck, district engineer in District 6. “The effort has tapped employee expertise across departments and has shown what a fairly simple, but innovative idea can do to improve our efficiency and financial effectiveness.”

District 6 has shared build instructions with 27 states, counties, and cities. Instructions to build a HIVE, including a parts list and wiring schematic, are available at

The HIVE is just one of the advanced inspection technologies included in MnDOT’s new Enhanced Culvert Inspections Best Practices Guidebook (see related story).