The first 15 slides have provided evidence that highway overpasses offer, at best, questionable tornado shelter.
Overpasses also offer questionable shelter from other severe weather phenomena.
It should be noted that there are countless other examples of this, these are simply 4 arbitrarily chosen events with which the lead author is most familiar. Despite the fact that 3 of these 4 events did involve a tornado, the problems under and around overpasses during these events were caused by the other severe weather phenomena - hail, wind and flash flooding.