Crashing your car into deep water!

Crashing your car into deep water. Now this is a lot more common in some countries than here in the UK although it does happen from time to time. Indeed some years back I fished a chap out of Llanelli docks after his car went in. He got lucky the tide was about half out, the top of his car was above water and he was more or less unhurt. In places like the US with a lot more bodies of water used for recreation and lots of unfenced roads it seems a lot more common. Now for many many years the official advice given was to wait until the car sinks to the bottom. Open a window slightly and let the water in. As the level rises the water pressure will equalise and you'll be able to open the door and swim away.... All well and good EXCEPT you'll almost certainly be dead if you follow that advice. More recent tests and studies have shown the above mentioned official advice to be leathal. You see first off many modern cars have electric windows and locks which probably wont work under water. Secondly and more importantly, test have shown that it can take as long as 5 minutes with the windows open for the presure inside a car to equalise enough for the door to be opened. Now if your name is Houdini or you happen to be the world breath holding champion this is fine... If your not your screwed! Modern advice is you bail out as soon as possible while the car still floats, dont wait, just get out quick. Get your seat belt off and shove the door open and get away.