We talked drone inspection of bridges. Above, beside, below, different kinds of bridges, At night, over people, roadways, that's an issue. Nights are important because thermal imaging works better in the evening, when the price increases at rental places, ha! Waivers and road clearances for drops or inspection. Waivers for crossing over a road. The most significant problem I have seen in PA is with the winter thaws. Water in the rock expands in the winter and cracks it, and when the ground thaws, the rocks tumble free of the slopes. Roads wash down hillsides. I would check the slopes around bridges. We have had incredible amounts of precipitation, even a tornado! last month. In Uniontown.
From aerial survey, it might be possible to predict and assemble work schedules from precise measurements over time.
One thing I was surprised no one talked about was using robotic craft to drive out on and over the ice on a winter's day or night to do checks on the bridge.
I know it sounds crazy, but I wanted to test a five pound craft on the ice, so I made a gelatin puck about 10 inches in diameter, 2 inches tall and chucked it out onto the frozen river. The megapuck shot across the ice, and the ice held. I didn't want to pollute the river or spend any money. I used stuff no one would eat. I made it entertaining.