People forget the infamous Maryland Amtrak wreck of 1987, which involved a stoned engineer. See http://en.wikipedia.org/wiki/1987_Maryland_train_collision
You state categorically that they were stoned. The wiki article only says they tested positive for it. The two are not necessarily related, due to the body's retention of thc for weeks after ingesting. But, I am sure you know that, if you have been reading the posts on this threadbut have an agenda.
FYI, I am not smoking anything but cigars these days... and wash it down with a glass of Cognac, Irish or Scotch Whiskey!
What are you drinking? There are many instances of ALCOHOL related crashes of all sorts, but most pot involved accidents are actually booze accidents with a sensational headline. I have juggled four balls when "stoned"! I could barely get them in the air when drinking booze... Just my opinion (and personal experience).