Driving On Ice

Caption: Partially submerged auto. Most cars sink nose first, like this one. (Courtesy Michigan Department of Conservation)

Source: Chiappetta, Jerry, (1966) Modern ABC's of Ice Fishing, Chapter 3, "Safety on the Ice"

Escaping From Submerging Cars
If you must drive out on ice, then you must break one of the safety rules of the open highway -- the rule of always wearing safety belts. Don't wear them on the ice. Be prepared to bail out – pronto!
Our studies on this subject and our experience have resulted in these suggestions: drive with all the windows rolled down and the doors ajar. Remember the resonance tables and drive slower than the critical speed. Keep a screwdriver or some other sharp object handy. If you start to break through, kick the transmission into neutral and bail out immediately.

Now, let's elaborate a little... Certainly some air will be trapped in if the windows are all up and the doors are closed, but your aim is to get out, not to keep the air in. The little air in the car will not mean much regarding flotation of a vehicle en route to the lake bottom... If you are driving a convertible, the best advice is to put the top down...

In examining state police records of cars going through the ice, we found most do not plunge like a rock... Troopers reported there was almost always a moment or two when alert ice fishermen could dive out across the ice, away from the break...

Police reported that the fatalities usually come, not in the initial sinking, but in the panic which follows. Fishermen get out, but they don't know how to get back onto the ice... They should... have some sharp instrument like a screwdriver, keys, or even a belt buckle to dig into the edge of the ice and hold on.

Footnote of Interest: Pronto's origins are early 20th century, from Spanish, from the Latin promptus.