This Trucker is Hauling a Very Unique Payload

Let me start off by saying, I don't normally break out my camera while driving down the interstate at 75 mph. Yesterday though, I just had too. I saw a very unique piece of cargo being hauled on a flat bed 18 wheeler trailer.

I snapped the pic below. Id' like to know the story behind this little Tonka Truck. Is some awesome dad hauling it for his little guy? Does it have special meaning to the driver? Have you ever seen a truck driver hauling a toy truck?