ST. PAUL, Minn. (AP) —  The Minnesota Department of Transportation has found drones to be reliably helpful in bridge inspections.

MnDOT will soon begin the second phase of a two-part study to determine the cost effectiveness of using the drone technology to gather close-up images of any structural flaws on the bridges.

Minnesota Public Radio News reports transportation officials say the first phase of the study found the drones were able to capture the same data as traditional methods of inspections from the ground using trucks, ladders and lifts. Four bridges were inspected in Chisago, Olmsted, Morrison and Washington counties.

Engineers will use a drone to inspect the Blatnik Bridge in Duluth during the second phase of the study in November.