Last winter a drunk drove into nearby Nassau Lake. He was very lucky to be rescued by a couple of volunteers.

http://www.lifesaving.com/spotlight/show_article.php?section=spot&id=624

When a car's side window breaks, it shatters into thousands of little rounded edge pieces. Had that happen when I was riding in the back seat at about age 7 and a dump truck backed into us. Glass sprayed everywhere but I was uninjured.

Now I'm wondering - could I get out of the side window of my car, wearing a winter coat? This will be a good thing to test. Even if I can't get out with the coat, I'll still wear the coat, I'm more likely to be trapped in a car on land than in water.