https://www.reddit.com/r/mythbusters/comments/130js6/breakin...
Automotive glass is not even glass really, it's more of a composite made up of layers of various transparent materials all designed to counter balance the weaknesses of the other layers. And windshields are bonded into the body of the vehicle with a very strong plastic adhesive.
Cruisers now tend to have cages to prevent this.
(This is not a solution if the car is underwater.)
1) Are you me? I've done exactly this because I knew that my car fit a 10' board. Turns out when you're buying rough lumber 10' sometimes means 10' 2".
2) The windshield is laminated glass instead of tempered. It'll crack much more easily, but it'll (more or less) stay in one piece in the frame instead of shattering out into a million tiny bits.
Wrong window. You're talking about the windshield which is a completely different type of glass than other windows.
Somebody on YouTube tested those emergency hammers and concluded they're basically useless. If you really want to break a tempered glass car window (I.e., any of them but the windshield), their recommendation was an automatic center punch.