A claw hammer? Well, having swung a sledge hammer and watched it bounce off a laminated screen, I was surprised. Of course a few blows later, it started to crack.

Mythbusters reported that a sharp point worked faster and more reliably. It's not the force as such, but being able to start the cracks, which is where that sharp point helps. If you use a claw hammer, don't use the normal place where you would strike a nail, but try to hit with the square edge of the side of the top, which will focus more force on a smaller area. And since side windows (if not bullet proof glass!) are toughened glass, which will be easier to start the crazing pattern The you still need to smash and clear it out - the edges are generally less sharp that 'plate glass' which is no longer allowed in cars, but you can still gash yourself.

If you CAN open the door at all, its preferable and faster than having to smash thru a window.