As crashes go this is a really dolly.
This video clip surfaced online a few weeks ago and from the vehicles we're thinking it is in the US.
The truck driver will surely be red-faced after the transportation of the huge beam goes spectacularly wrong.
Footage is from one the unit's escort vehicles.
While the truckie successfully negotiates the first corner the dolly trailer at the rear swings wide on straightening after a second curve and ploughs into what appears to be lane dividers.
The crash results in the beam being dragged off the dolly and it then becomes a simple case of physics as the huge weight of the beam takes over and rolls to left, flipping the truck on its side at the same time.