A car doesn’t go straight to 80’, if it did you wouldn’t survive the initial impact. Have a tool available to break the window next to you, and get out and up to the surface. Forget the spare air, unless you are wearing it in a survival vest as I wore when flying, you’ll probably drown looking for it - time is precious. If the water is very cold, make sure you go into the water where first responders are readily available. Even then it might not help.
Air Florida Flight 90, WA DC, Feb. 1982
Lots of people around who could do very little to help due to ice in the river. It’s preferable to get real wet when the weather is warm.