US 95 Idaho

Deploying Drones to Reduce Construction Risk on Idaho's Major North-South Highway Corridor

Project Manager Details Technology's Use in Quantifying Earthwork, Equipment, Materials and Personnel

Ty Bardwell, P.E., served as our project manager for design and construction management on the U.S. Highway 95 Granite North project in Idaho, where he also piloted drone flights to monitor construction progress.

Q. What access or data challenge did you have? 

A. Planning for drone flights was a challenge because access changed almost daily for the first season of the project. Instead of planning flight mapping perimeter in the office, we adapted to creating the actual perimeters in the field based on access and sight lines for that day. Data processing was a challenge in the beginning because it was the first time HDR used the combination of Propeller AeroPoints survey as temporary control points, tying in the flight with real-world coordinates in conjunction with Pix4D photogrammetry software for post-processing the data. We developed a workflow and instructions for this process to make it easier in the future.

Q. Who piloted the drone flights? What went into drone flight planning? 

A. I performed the flights with observers who had taken HDR flight observer training. Typically, I was joined by an inspector who was already working on the project. Flight planning at HDR is done through Drone Logbook. It consists of developing a job hazard analysis for drone flights on the project, plugging in boundaries of anticipated flights, checking airspace requirements, and getting flights approved. Then, prior to each flight, we checked to confirm weather conditions were conducive to flying and laid out specific mapping perimeters for that day’s flights.

Q. What type of drone was used? 

A. DJI Phantom 4 Pro RTK

Q. What did you learn about construction staging, equipment and personnel? 

A. On a large earthwork job, the construction staging and equipment is constantly changing. We needed to be flexible and make modifications with flight planning on each flight, working around the current operation. We confirmed that this is an effective, relatively low-cost way to quickly get a snapshot on a regular basis of staging, equipment and progress of work. This reduced risks for the owner of potentially paying for work, equipment and materials in the case of a quantity discrepancy or other dispute on the project.

"The use of drone technology is a game-changer for owners in minimizing quantity dispute risks. It helps them quantify actual conditions and costs at a given point in time."

Q. How was the drone data applied? 

A. We were able to create a digital terrain model (.dtm) file from each flight, mapping along with isometric-type photos to use for public outreach and planning. This information was available to the team when issues came up — planning and implementing changes to the contract without having to make extra trips in the field to measure or take pictures of the area in question.

Q. What were your impressions of the data gathered? How did drone data inform design and construction? 

A. The data was amazingly precise. It’s amazing to see how much accuracy can be obtained from taking photos with a drone roughly 300 feet in the air. This is the first earthwork project I’ve been a part of where the earthwork quantities were right in line with design estimates, and there were no earthwork quantity disputes with the contractor.

Ty Bardwell
Construction Project Manager
Resident Engineer