Dargo - A couple years ago I was on my way to Jacksonville on US 301 when I saw a pickup approaching towing a tractor. The US 301 there is 4 lane ... I was interested to see what tractor he was towing and then I saw the whole trailer. The tractor was a 4xxx, must likely a 47XX so it was of some good size and weight ... then I see there are two yellow straps "securing" it to the trailer. One strap went across the trailer by going over the tractor's hood ... the other strap went across the trailer by passing over the transmission area like the one in the picture you were talking about. The straps appeared to be about 1-1/2" or 2" wide! No other tie downs!
Leo