The windshield repair guy is correct: there is no way to repair cracks in the windshield. (mechanics.stackexchange.com)
If you do have a substantial crack in your windshield, the strength and safety of the windshield has likely been compromised. (trustedchoice.com)
The work could also reveal how fast a car was moving just before an accident, by looking for cracks in the windshield created by stones kicked up from the road. (newscientist.com)