I have seen that several times since I got back to the states, Flat bed drivers like doing this a lot! I think it's cool!
After looking at your pics a number of times I did see the Tonka Truck. Good catch. I went through many of those trucks as a kid. One of the best toys ever. I always wanted the front end loader to go with it.
I had the complete Tonka set. The front loader, dozer, dump truck, and the crane. Spent countless hours with them all on a small dirt pile in the back yard.
When all my Boy Grandchildren, had their First Christmas, they each received a Tonka Dump Truck, from GrandPa.... They are ALL teenagers, NOW but they STILL ALL have those, as Prized Possessions....
I still love the "OLD" Tonka toys, the ones where a kid actually had the risk of loosing a finger playing with it! Now days, they are half plactic and no where as rough and tumble as they used to be! Remember the Tonka Add?