New US Container Line

A 40’ container has a recess in the ladder construction underneath the container at the opposite end to the doors that locks in to the container chassis to give the chassis rigidity in North America. I am unaware of anywhere else where the trailer relies on the container for some of its load carrying service.
Other jurisdictions including here use Hub odometers for tax purposes and a heavy trailer is licensed and charged separately from the prime mover.
A standard truck or trailer can have a deck with twist locks imbedded in the deck or have no deck at all but in each case the trailer has a substantial girder arrangement. In the case of swing lifts adjusting for 40’ or 20’ the twist locks are mounted on the base of the arms. This slides on steel rails as required. Major trucking companies in urban areas load one swing lift to an urban area with its first load and then it will load or unload conventional truck and trailers within that area.
You would not use a swing lift on long haul because you lose payload.

Looks like the idea of using 53’ containers for delivery of goods from China to US is not so far fetched as I thought:

Genco Pyrenees is a geared bulker, 58K DWT, Blt. 2010:

PS What happens to the empty 53’ containers?
Do they go back to China for another load, or get sold for reuse in the US??

APL ran 53 footers USWC - China for a while

2007:

2013: