With cameras alone it seems pretty easy to trick them into dismissing road signs as nonexistent.. I think Lidar alone should be telling you there is a sign, so your camera is faulty or someone is putting up blank signs.

Lidar as I was told to use it would be in conjunction with a database of way points like signs, so the trouble would be knowing if the sign was updated.

My car doesn't seem to have any trouble reading temporary construction speed limit signs and the like. And it has lidar. This seems to be a solved problem.

Are you saying it exclusively has lidar? If not then I don't understand your comment.

It also has cameras. I might have assumed too much.

I don't know how it determines the existence of a sign. It might be visual, lidar, or a combination.

I think I drew a faulty and unstated inference. Feel free to disregard.