UPDATE (Nov 7th 10:39 EST): The Tesla Model S in question reportedly struck a tow hitch on the road, and ”hit the undercarriage of the vehicle causing an electrical fire.”
A Tennessee Highway Patrol spokeswoman (Dalya Qualls) stated that “The driver, identified as Juris Shibayama, struck a tow hitch that was in the middle of a lane, which damaged the car’s undercarriage and caused the fire.”