Roof Crush Cases:
Roof crush defects affect virtually all brands of SUVs, Mini Vans, 15-Passenger Vans and Light trucks sold in America, as well as some passenger cars. The Federal Motor Vehicle Safety Standards, FMVSS 216, applies to roof strength for vehicles manufactured in the United States. The rule as written allows roofs to be so weak that it provides nearly no protection whatsoever. In fact, vehicle roofs get up to 40% of their strength from the windshield of the vehicle. Interestingly, the continuity of the windshield is one of the first things to go during a rollover crash. Accordingly, when both passenger side glass and windshield glass shatters during a rollover crash the roof no longer provides even the minimal strength of FMVSS 216, in fact if tested without a windshield or side safety glass the roof would crush upon itself on the vehicle weight alone.
In fact, Volvo, one of the leaders in automotive safety engineering suggests that for optimum safety vehicles should come equipped with laminated side glass as well as pre-tensioners on the safety belts, and both frontal and side curtain airbags. Pre-tensioners are inexpensive devices that fire a pyro-technique charge milliseconds prior to impact, which tightens the seatbelt and keeps the occupants in their seat during a rollover sequence. Without these pre-tensioner devices studies have shown that even while wearing a lap and shoulder belt the centrifugal and centripetal forces of rollover accidents would allow occupants to become partially extruded from a vehicle during a rollover accident.
Pre-tensioners also would help eliminate spooling-out of seat belts, which also allow for partial extrusion of occupants during rollover crashes. The costs of pre-tensioners can be as little as five dollars.