There are two main types of safety glass used in automobiles today---laminated glass and tempered glass.
History
Regular plate glass was used in the early 1900s when auto companies first began installing windows in cars. It was soon realized that this was very dangerous when the glass broke, and between 1919 and 1927, the option of laminated glass windshields was introduced. To further improve safety, car manufacturers began using tempered glass for the side and rear windows during the 1940s. Modern cars use only laminated and tempered glass.
Function
Glass came into use as the speed of cars increased to protect the occupants from wind and flying debris. Plate glass was able to protect the occupants from the wind, but debris and collisions often broke the glass into dangerous shards. This prompted car manufacturers to use what is now called safety glass.
Benefits
Laminated glass is always used in windshields because it does not shatter when impacted like tempered glass. Tempered glass is used in the side and rear windows.
Significance
The reason that the two different kinds of safety glass are used in automobiles is because of accident safety. Laminated glass is much more difficult to break through than tempered glass. When trapped in a car, the occupants or rescue workers can break through the side or rear tempered glass windows much more easily than the windshield of laminated glass.
Features
Modern windshields can now include a wide variety of options such as UV protection, defrosting capabilities, shade bands, antennas, rain sensors that activate wipers or convertible tops and even holographic displays.
