I was on a business trip when I heard the news of the collapse. In the confusion of the moment, a lot of things get reported that later turn out to be incorrect. One thing I heard yesterday was that a freight train was passing over the bridge at the time of collapse (I've seen some combination auto/train bridges but I have no idea if this bridge was one of them). If that's true, there may be some other possibilities as to what triggered the collapse. For example, if the train somehow derailed at that point or had some load shifting, it might have struck a support. Several years ago, I read about a bridge that collapsed when it was struck by a barge. If there was a train going at the same time, perhaps there is a connection to the collapse. Of course, it could've just been a coincidence or a completely inaccurate news story in the first place.