This looks like a hitch failure. I had one last spring in Houston going to Mexico. I just had a U-Haul
brand new hitch installed by U-Haul
at Baton Rouge. I wanted to be sure that every thing would be perfect for that long trip. My original hitch was really rusted. The new hitch broke just in the middle where everything is welded. It is quite evident that this "mechanical failure" is related to a weakness of the new hitch!!
I happened an early Easter morning on I 10 just in the middle of Houston (5 lanes). I was driving at normal traffic speed and suddenly BANG. I saw then, in the central mirror, my small trailer (Trilium 13 feet) loose on the highway going in all directions. Everyone saw it and the traffic jammed instantly on the 5 lanes!!!!!!!
I was pretty lucky. The trailer didn't rolled over and gently stopped on the Jersey separation. Unbelievable taking into consideration the circumstances. There were only minimum damages but it could have been a real disaster and peoples killed.
You can see a few pictures on my blog (written in French) just right here
By the way my insurance company paid for everything but U-Haul
refuses any kind of responsibility except the part replacement and even then because I took their extended guarantee the day they installed the hitch . Believe it or not and keep this in mind when you buy or get a new hitch installed by U-Haul...