Surprised no one is even suggesting the possibility.
Shep said early on that Homeland Security said this did not "APPEAR" to be a terrorist attack...............
Things make you go "hmmmmmmmmmmmmm"
There are certainly some cameras of some type in the area of the bridge. If so, it would be prudent to look at the tapes, if any, to see what was on the bridge at the time of collapse. That would help the rescue/recovery teams in looking for specific vehicles. The sooner they do this, the better. I hope that no one was killed, but that may be the case. It would be a miracle if there were no fatalities.