As you'll see in my profile, I have a Proline Styling windshield protection product to prevent my FOURTH vehicle windshield from breaking (3 on my "other vehicle" convinced me I had to SOMETHING - ANYTHING - to stop the bleeding) in the last 18 months (and no - that's NOT a typo).
If you're not familiar with the product and want to know more about it on contact them to find either a distributor in your area or buy it directly from them, here's the company's website link: it has videos, etc. about the product along with demos:
http://www.prolinestyling.com/
If you want to see actual videos of somebody shooting rocks at a windshield at relatively high speed without the product then one with it, check this out: