I'm not a glass expert but I have seen many shattered car windows. They are tempered glass and break in small squarish pieces, not sharp shards. I personally cleaned up my car after a passenger window was broken in by a thief. <br><br>It's been a few years, but I certainly don't recall a bunch of razor sharp pieces of glass.<br><br>Am I missing something? Isn't that the whole point of tempered glass which is used in sliding glass doors, showers, car windows?<br><br>See http://www.sciam.com/askexpert/physics/physics59/<br><br>JustBob.