Way back in 1919, when they were first installed in automobiles, windshields were recognized as essential to the safety of the vehicles’ passengers. Back then, the passengers of the new “horse-less carriages” needed protection from any airborne articles and the wind generated by 5-8 mile per hour speeds. The windshields in today’s vehicles have evolved with the cars and they have become a fundamental part of the vehicle’s ability to protect occupants in normal driving and crash situations. The windshield is as much a part of the vehicle’s SRS, or Safety Restraint System, as the air bags and seatbelts. The SRS is designed to keep passengers within the relative safety of the passenger compartment during an accident. When any one of these components is damaged or inoperable for any reason, the effectiveness of the entire system is compromised.
How does a windshield protect the vehicle’s occupants and what happens when a windshield’s strength is compromised by damage?
In every-day driving conditions, drivers can expect to be bombarded by various kinds of road debris that can cause extensive damage to the windshield. For this reason, windshields are made of two layers of glass that sandwich a piece of laminate called PVB, or polyvinyl butyral laminate. The laminate inner layer acts as the safety layer of the windshield holding it together under extreme impact. This allows rocks, gravel, and who knows what else to bounce off your windshield, rather than coming straight through or shattering the entire piece of glass. All OEM windshields are carefully engineered to have a certain amount of tensile strength. Tensile strength is the maximum stretching force or twisting that a material can withstand before breaking. If windshields already have cracks or chips in them, they can lose up to 70% of their tensile strength. If another rock hits the windshield, the windshield may not have the strength required by the manufacturer to keep vehicle passengers safe.
During A Crash…
That’s only the beginning of the windshield’s role as a safety component, however. As cars have become much more streamlined in design and the use of complete metal has been abandoned, in most cases, the windshield has become critical in the vehicle’s overall stability and ability to protect its passengers in crashes. First of all, it is a federal safety standard that windshields keep passengers inside the car in the event of a crash. The driver and all passengers should always have seatbelts on, but if they don’t it becomes the windshield’s job to help keep them inside the vehicle.
During crash circumstances, windshields also play a vital role in the structural integrity of the vehicle. In front-end crashes the windshield provides stiffness and rigidity, which helps keep the car from crushing on impact, and protects the bodies of the passengers. In rollover crashes the windshield is responsible for reinforcing the roof structure and keeping the roof from caving in on the passengers. The National Highway Traffic Safety Administration reports over 40,000 Americans are killed and over 5 million injured every year in highway crashes. Over 30% of the fatalities occur when vehicle occupants are either ejected from the vehicle, or, injured during rollovers.
If a windshield’s strength is in a weakened state because of chips or cracks, it does not have the ability to keep passengers inside, or to withstand the crushing forces an automobile experiences during a crash. Industry experts estimate that between 18 and 22% of a vehicle’s structural integrity is provided by the windshield and in roll-over accidents, the windshield makes up as much as 70% of the total structural integrity of the vehicle. Do you want to compromise that much of your vehicle’s strength because of a windshield crack or chip?
When The Airbags Deploy…
In-dash airbags are designed to explode against the windshield and use it as a “backstop” as they deploy. The airbags impact the windshield at speeds of 150-200 miles per hour, so needless to say, it is critical that the windshield’s strength has not been compromised for the airbag to work properly.
When the airbag deploys, weakened spots in the windshield make it hard to withstand the blow of the airbag. If the windshield has the slightest damage, or is not sealed properly, the airbag can actually break through the glass or cause the windshield to pop out of the car completely. When this happens, the airbag becomes useless, and the passenger is still in danger of hitting the dash, or being ejected from the car.
As stated above, taking care of windshield damage is much more important than simply being annoying or ugly. Damaged windshields present legitimate safety issues for drivers and passengers of the vehicle. Since most consumers don’t know what damage can be repaired or not, it is very important to contact a knowledgeable company that will do a good job. As always, repairing the windshield saves the customer money, but more importantly saves the factory safety seal by not replacing the windshield and restores the windshield’s structural integrity.
Watch this video of a 20/20 special a few years ago.