Honestly, no there really is nothing you can do to prevent that. You can just be more cautious about where you drive. Try not to drive on gravel roads or dirt roads. This will lessen your chance of a rock hitting the windshield.
Stick to well-paved roads. Otherwise, contact the government entity responsible for the roads you travel and complain (or send them a bill! ). Avoid driving behind trucks carrying rocks.
I would recommend increasing your following distances from other vehicles, particularly large, tall vehicles and semis. Otherwise, there isn't a vehicle modification or such thing that I'm aware of.
