SparticleBrane
Contributor
Gary D.:Once the vehicle is flooded the PSI equalizes and the doors will open and close unless crash damage jams them.
Gary D.
Actually--
If you can get your hands on the 3rd episode of the 3rd season of Top Gear ( bbc.co.uk/topgear ) they tested this theory.
They dropped a car with one of the presenters of the show inside it--into a ~40ft deep pool. Thankfully there was a diver in the car with him and divers in the pool at various depths. Richard was unable to open the door untill he was on the bottom of the pool--and he had to be given air by the diver inside the car before he hit the the bottom.
As it turns out, the pressure inside the car is always LESS than the pressure outside the car (even if it's fully flooded!) when it is still sinking. The pressure never has a chance to truly equalize until the vehicle is resting on the bottom--and who knows when that'll be?! Could be 10 ft...could be 130ft...
They did the test again but instead of waiting for it to fill with water he pushed the door out as hard as he could--he struggled but he finally got it open before the car totally flooded.
So as it turns out the myth of "wait for the pressure to equalize" is BS--get out of the car AS FAST AS YOU CAN, no matter how.
As long as there is no damage to the window and the key is in the igniton, car windows will still work even if the car is flooded.