I don’t know how common they actually are, but I see car window breaker & seatbelt cutter gizmos being sold all over the place. I know I keep one in my car where I can easily get to it, though my car emergency kit is probably better stocked than most people’s, and most first responders also have them in their kit.

Also an automatic center punch will usually do the trick as well, it’s a fairly common tool, though in an emergency it may not be practical to go rooting through your toolbox to find one.