Q. Don’t these guards move when someone drives over them?
Surprisingly the fact that a vehicle tire is so much larger in diameter than the first pipe contacted the initial force is downward from the vehicle tire, stabilizing the guard in place… not pushing the guard forward. Some folks push up a little road material to the edges which also makes them smoother to cross. The chains on the side guards help hold it in place as well.
Q. Don’t these fill up with debris or mud now and then?
Not as often as we thought they might. Rains help remarkably well to clean them out. But if they do get filled, it takes about 20 minutes and a chain to drag the guard a few feet and re-set. Very easy to maintain. Much easier than getting heavy equipment and lifting out old style grates set over pits and shoveling when they fill up.