The number one killer of children of any age 4--34  is an automobile accident .Per  100,000 population the ejection  fatality rate in the US is 14.7%  In the state of Al. it is much higher  24.8%. In the rural areas it is much higher still ,  Crenshaw Co. 29.14%  Pike Co 37.11%  Barbour Co 45.75% and Bullock Co .72.37%  In 2002  40% of all teenagers  who died were killed in an auto accident . 29% of these deaths were due to being  ejected  [ thrown out ] the glazing.  Studies by  NHTSA have shown death or serious injury to be much more likely if ejection occurs .For this reason NHTSA mandated the  [HPR ] high penetration resistant windshield. Once made of cellulose, the inner layer of an [OEM ] original equipment manufacture windshield is now made of polyvinyl butyral. It is designed to stretch upon impact and hold the person inside the car. The glass is designed to peel away from the vinyl to minimize lacerations.  The airbag uses the windshield to support it as a backstop if deployed in an accident There is no  backboard  if the entire windshield pops out .  Because of the tremendous pressure placed on a windshield when impacted by both the airbag and the vehicle occupant or in a rollover accident NHTSA has mandated changes in windshield retention materials . Some of the SHADY BUNCH glass shops who have chosen to ignore the law still use only butyl or they may reinforce  the butyl  with a thin bead of urethane which still doesn't  meet FMVSS  212, 208,  219. or  216. Todays  urethanes have more than 1000 lbs. tensile strength . Butyl has only about  8lbs tensile strength. Urethane is Not generic . One chemical composition Can NOT be used on just any vehicle. Chemicals from one system cannot be mixed with chemicals from another system .    There are chemically specific  primers and rust inhibitors which must be used precisely as designed in a urethane system. These are  expensive .They  have a  short shelf life.  Once opened they must be used in a very short time or be disposed of. I am afraid this is where  more of the Shady Bunch cuts corners .We work on many water leaks where the installer has used a cheap grade of urethane but not the whole system and either the glass is not bonded to the urethane or the urethane is not bonded to the car , usually the latter. All new vehicles are crash tested with an OEM Windshield firmly bonded  to the car. Engineers designed this vehicle with the windshield  playing   a major part of the SRS [Safety Restraint System ].It Must Strengthen and Reinforce the passenger cabin of the vehicle. The OEM  Windshield  Glass  itself Must Pass FMVSS 205. Many New vehicles  Barely Pass Roof Crush test . They   Would Not Without the Windshield ,especially  SUVs and some extended cab pickups. In 1982 General Motors did a study of rollover occupant ejection and concluded back then that a vehicle lost about 1/3 of its roof strength if the windshield  bond came loose. Ford Motor Co. also  did some test  with unsatisfactory results Some  estimate  An OEM Windshield----Properly Installed ---can provide up to  45% of  the cabin strength of a vehicle in a frontal collision and up to 60% in a rollover .