Jim Halsey: Do I look like a killer to you?
Proprietor: Well, what happened to you?
Jim Halsey: Nothing.
Proprietor: Nothing?
Jim Halsey: Nothing happened.
John Ryder: You wanna know what happens to an eyeball when it gets punctured? Do you got any idea how much blood jets out of a guy's neck when his throat's been slit?
Jim Halsey: What do you want?
John Ryder: I want you to stop me.
Jim Halsey: Why are you doing this to me?
John Ryder: You're a smart kid... figure it out.
Answer: The windshield glass would have not broken this easily (like regular window pane glass in your home or such). I am going to guess that kind of glass hasn't been used on car windshields since at least the early 70's, if not before. The Sheriff's truck didn't appear to be that old, either.