I find it hard to believe he was backing up though if the drive way was long.
You can go to google maps and see his house.
No long driveway, at all ! — neighbors right on top of him. Waterfront gazillion dollar row houses. The only thing blocking the neighbors are trees, lots of trees.
My guess, he put the pedal to the medal and immediately slammed into whatever was in the way.
go here, his house in on the right:
http://www.orlandosentinel.com/news/local/breakingnews/os-bk-tiger-woods-accident,0,1369881.story
;-)