More information I've read.
It wasn't a true lowboy trailer, rather it was a hydraulic platform trailer. Hard to tell from the video, but it looks like the type used was not the typical 5th wheel setup.
Similar to this although with a closer coupling, based on the video images.
The Pilot cars were, as is usual, contracted from a pilot car company familiar with the area.Law enforcement escort was part of the permitting requirement by TXDOT.
The trucking company has been in business for a little over 40 years with up-to-date DOT inspections, and has a good safety record per the DOT's SAFER program
I work in aviation logistics where we have FAA and DOT constantly monitoring, so right now I am strictly looking at this tragedy from an operational standpoint. It will be informative to read the NTSB prelim report in about a month or so.
As with aviation, incidents can eventually be traced back to one point of failure. What may seem obvious to any of us, may not be so.