2.  Overpasses are safe tornado shelters.

This is one of the most dangerous misconceptions about tornadoes.  During the F5 tornado that struck the Oklahoma City Metro on May 3rd, 1999, there were multiple fatalities resulting from people seeking shelter under highway overpasses.  An overpass creates a tunneling effect that increases wind speeds as the winds compress to travel beneath the overpass.

tornado highway overpass
This storm chasing video shows cars blocking a busy interstate during a tornado warning.

Any person who is caught in these winds will likely not survive as the winds will also carry very fast debris as well.  On top of this, parking beneath overpasses during severe weather is ill advised and can create a traffic jam that prevents emergency services from being able to do their jobs.  If you are caught outside and absolutely cannot escape an approaching tornado, the safest thing to do is quickly locate the lowest area around you (such as a ditch) and lie as flat as possible while covering your head with your hands.  If you’re in a vehicle, be sure to pull completely off the road before exiting.

Laying flat in a ditch may sound scary, but the idea is to keep the winds above you, not under you.  Tornadoes don’t really “suck”, they instead “lift”, and in order to lift, the winds have to get beneath your body.  Sheltering in an overpass puts you directly into the strongest winds.  Don’t do it!