"Witnesses indicated it just veered off, hit the embankment, and was unable to gain control," police spokesman Lyle Gensler told WFAA.
The video above, recorded by North Texas Tollway Authority cameras positioned on President George Bush Turnpike, capture only what happened after the 18-wheeler was already airborne.
Long was killed in the crash. First responders were reportedly unable to free him before the cab burst into flames.
The truck belonged to B&M Trucking of Gallatin, Tennessee and was carrying a load of ceramic tile.