Do You Know What It Means?

You see these signs all over the country side but do you know what it means?

My sister, who doesn't live in these parts and doesn't live in the country, when she was here visiting a long time ago asked, "What the heck are all those signs about? Does it mean there are trucks buried in the ditches everywhere?"

So almost every time I go past one of these now, I think of my sister and I get a little smirk on my face.