The use of drones for bridge inspections can create an overall average cost savings of 40 percent without a reduction in inspection quality.

MnDOT assessment of drone-use as part of a risk- based approach to bridge inspection realizes safety, cost and quality improvements.

Date Posted

Utilizing UAS and Reality Modeling to Improve Bridge Inspection Result

Summary Information

The Minnesota Department of Transportation (MnDOT) is utilizing drones to collect and process large amounts of data during bridge inspections with the goal of improving the quality of bridge inspections and improving safety for both inspectors and the traveling public.

In the summer of 2015 and 2016, a research team implemented Unmanned Aerial Systems (UAS) technology on 39 bridges including a wide range of bridge sizes, types, and locations to demonstrate the benefits and challenges of employing UAS on a large scale. Applications included using the drones to survey confined space inspections in steel and concrete box beams and pier towers, as well as inspections between beams for multi-girder bridges and bearing inspection for beam bridges.

Data was collected primarily from an imaging payload intergraded into the UAS body. Case study inspection reports were compiled for a select number of bridges representative of various use cases.


  • Drones can reduce the safety risks of bridge inspectors by removing or reducing the need for traditional access methods such as Under Bridge Inspection Vehicles (UBIVs), rope access, ladders and scaffolding. Additionally, drones can reduce the risks posed to both the public and bridge inspectors by eliminating the need for traffic control and the need for inspection personnel to work near traffic.
  • The cost savings from removing traditional bridge access methods were significant – ranging from $540 to $21,000, with an overall average cost savings of 40 percent. Even where there were no cost savings exhibited, the quality of the deliverables was greatly improved. Though difficult to quantify, additional cost savings were expected from the improved inspection information drones provide, allowing bridge owners to make better risk-based investment decisions on bridge repair, replacement and maintenance needs.