Could a Sonic Boom Crack a Windshield?
September 23, 2014I had to make a call to my insurance agent today to report a claim on my broken front windshield. My explanation for the needed repair sounded almost as absurd as “the dog ate my homework,” but the only direct link I could make to my windshield cracking was that a sonic boom broke the glass. I had gone to watch the Blue Angels Navy flight squadron fly over the Baltimore Inner Harbor as part of this month’s Star Spangled Spectacular, which is celebrating the 200th birthday of the writing of the Star Spangled Banner lyrics by Francis Scott Key. The Navy jets are VERY loud and I had parked my car at Martin Airport to see the take-off and landing of the squadron.
When the show was over and I returned to my car, there was a pretty big crack in the middle of my windshield, with no apparent indentation from a rock or any other projectile that might have done damage. Could it have been the sonic boom from the fighter jets, the solar flares that caused geomagnetic storms last weekend, or some other unexplainable act of mother nature? Actually, according to www.carwindshields.info, there are stress cracks that can appear in a windshield without any obvious explanation – but though mysterious, the stress cracks usually come from one of these common underlying causes:
Temperature changes – One of the most common causes of stress cracks is due to extreme changes in temperature. For example, if it’s an extremely hot day, washing the car with cold water could trigger a stress crack. The same is true of using hot water to melt an icy windshield.
Pressure changes – including wind pressure, can also cause stress cracks. For example, explosions send out shock waves which rapidly change the atmospheric pressure in a large radius from the blast zone. Cars located many miles away from the explosion can have blown out windows or cracked windshields.
Structural weakness/defects – Windshields play a vital role in the car’s safety systems. One of those roles is to support the roof in the case of a rollover accident. Another is to deflect passenger side airbags upon deployment. As such, windshields are installed with a strong adhesive. Uneven pressure can cause stress cracks. Manufacturing defects can also contribute. For example, when glass is annealed (heated and then cooled) during the manufacturing process, “residual stresses” are often found along the perimeter of the windshield. As a result, the edges of the windshield are also the weakest and most prone to fractures.
So what does this have to do with finances and my own financial well-being? Well, my first thought had to do with the fact that I had recently increased my deductible to $1,000 to reduce my auto insurance premium and windshields are probably expensive – especially since the crack had appeared at the edge of the embedded antenna in the glass. Luckily, glass repair is covered under the “comprehensive” section of the policy (where the deductible is only $100), not the “collision” section (where my deductible is $1,000). According to my agent, if I take advantage of my insurer’s glass program they will connect me with an affiliated glass shop and help me schedule an appointment for an estimate. Since repairs are cheaper than replacement, my insurance company will even waive the deductible if I opt for a repair if that’s possible.
I am very thankful I didn’t drop the comprehensive coverage on my vehicle when I paid it off a few years ago, since legally you are only required to carry collision insurance, not comprehensive. My annual cost for the comprehensive portion of my auto coverage is only $137, well below what it would have cost if I had to replace my windshield on my own this week. So take a look at YOUR auto insurance policy, verify you have comprehensive coverage, and stay away from the sonic booms and solar flares.