How to escape a sinking car

Now, I am perfectly well aware that almost nobody ever has to escape a sinking car, and the possibility of me ever being trapped in one is unlikely, but as I mentioned before, that sort of thing fascinates me.
   So, let's say you're cruising along a road fifty or so feet above river or lake of some sort. It's late at night so you don't see the corner until you've flown off it. Next thing you know, your car is splashing into the frigid waters.
   No need to panic, there are only a couple things you need to remember. First take a huge breath, then kick out the window on your car door. This will allow you to open it. Immediately open the door and swim up as fast as you can, and your home free! Not like that will ever happen...