get better advice.

Even in Idaho and oriented flat. I think the heavy glass surfaces must be blocking more than they figure or is bending the light away from the actual cells with the sun at an angle.

Could also be "soiling" or dirt accumulating on the surfaces.

They have some other serious problems here though.

Do they block the light at all? Do they “scuff” the surface with the grit on their shoes?

Hard to get much use of something that was poorly designed and badly manufactured, and was never meant to function efficiently. That probably explains why, "the program was supported by political leaders like Idaho Republican Sen. Mike Crapo."

Putting solar panels on a roadway is mind-numbingly idiotic.

There are long stretches of rural interstate where it's 2 lanes on each side and a huge grassy median strip. Why not build solar panels there, sell the electricity as part of a public utility. You aren't even clearing new land since its already otherwise unusable because of the interstate.