I read somewhere that a high percentage of such accidents were suicides. There was a kid in my H.S. whose father was a member of the NYC Council. His father died, much younger than 70, in a similar accident. I always suspected it was one step ahead of a grand jury true bill of indictment.
I remember driving south on the Belt Parkway one Sunday, just south of Belmont Park, a huge traffic back up. Some guy in a GTO had center punched a bridge abutment. You could see him sitting dead, face covered in blood, bolt upright in the drivers seat. I always suspected he left the mortgage money at the track.