NWRA President's Column: The Crystal Ball

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For 27 years I have documented windshield damages on my invoices. These show an outline of a windshield where we draw the damage, measure it, mark the impact point and name the type of break. I have also personally done parking lot studies in many states and paid for one in Denver. The parking lot studies match my business records within five points. My real-world studies (business records and parking lot studies) also closely matched ten years of a large insurance company’s repair and replacement statistics.


In southern California where I operated a repair-only business for ten years, 97 percent of crack repairs were edge cracks with only 3 percent floater cracks. A floater crack is a stone-break/chip that cracked out. An edge crack is a crack that runs to the edge with an impact point in the weak spot and it cracks immediately upon impact due to installation stress. The temperature in Southern California was not severe enough to cause stone-breaks to crack-out but it is warm enough inland so that impacts cause stone breaks and impacts in the weak spot would cause an edge crack. 

Parking Lot Studies Show Cold Temperatures Debunked, Lab Test Prove Invalid

 In Colorado, where I have a repair and replacement business, one out of every three vehicles has a stone break, 17 percent of vehicles have an edge crack and approximately one out of ten stone-breaks cracks out into a floater crack.

As you may or may not know glass is more robust when it is cold because the glass molecules are contracted. When it is hot the molecules expand and it fractures easier. The same stone impact in the winter that does nothing would cause a break in the summer.

In the later part of December and the beginning of January this year in Colorado hit below zero degrees Fahrenheit overnight with daytime temperatures in the teens and 20s. I anxiously waited for the phone to start ringing off the hook because if that test were true than approximately 40,000 of the 150,000 vehicles in the county where I live would have cracked windshields during this cold spell and among the 14 auto glass shops in my county we would all be inundated with business. But it did not happen; the windfall did not arrive.

So I decided to brave the cold and go out and do another parking lot study, and here is what I found.

January 3 and January 4 the overnight temperature was -6 to -8 below 0 degrees Fahrenheit. In the morning of January third while it was still less than 14 degrees Fahrenheit I went to the Sam’s Club parking lot, but I had forgotten gloves and after 25 vehicles the pen froze. So on January 4, I went to the Wal-Mart parking lot and surveyed the remaining 75 vehicles (had gloves and a pencil this time). Out of 100 vehicles there were 45 chips, five of which had cracked out; ten edge cracks and; two miscellaneous breaks. 

Why do I believe the lab test is not a valid predictor?

1. The windshields were not installed so there was no induced/installation stress, which I believe plays a key role in whether they crack, whether they crack horizontally or vertically and whether they go to the edge or not;
2. The different types of stone breaks were not accounted for (i.e. a star versus a partial bulls-eye, for example);
3. The one paying for the study may be trying to justify something;
4. How many vehicles are garaged versus un-garaged plays a key role; and
5. I do not think that a lab test predicting crack-off can duplicate the variables in the real world the way that business records and parking lot studies can. Parking lot studies have the variables of type of break, temperature, weather, climate and topography in a particular area and business records have the variables of type of break, temperature, weather, climate and topography and human/consumer action. So my conclusion is the real world prevails over the crystal ball.

Richard Campfield is the president of the National Windshield Repair Association and founder and president of Ultra Bond Inc. in Grand Junction, Colo.

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