Every year in the U.S., about 8,000 fatalities occur in side impacts, and about 9,500 fatalities occur in vehicle rollovers. Severe head trauma and spinal cord injuries are the prevalent traumatic injuries that are directly related to the extent of inward crushing or intrusion into the occupant's “survival space” and to the rigidity and shape of interior edges and surfaces.
Based on accident evaluations and assessment of available technologies, there are feasible and practical advanced design features for vehicle bodies and interiors that can concurrently enhance both side-impact protection and rollover roof-integrity protection:
Strengthened vehicle body by the use of rigid-foam-filled tubular members that strengthen and stiffen the vehicle body, by tripling resistance to bending and compression. Strengthened doors with full-perimeter overlap and multiple latches. Multi-layer laminated floorpans, cross-panels, and roofs of composite materials. Roof tubular members in an interconnected design, with full-length internal stiffeners and/or rigidfoam-filled. Wrap-around stronger seats with taller headrests, and integral seatbelts and belt pre-tensioners that activate in side impacts and when rollovers are initiated. Energy-absorbent closed-cell padding of interior surfaces, some with a metal-air-gap underlayer. Side airbags for torso and head protection. Side window glass-plastic glazing and perimeter bonding, to cushion head impacts and prevent occupant ejection from the vehicle.
The main objects of these safety upgrades are to (A) encourage deflection of the striking vehicle and struck vehicle away from each other, (B) minimize intrusion into the occupant's “survival space”, (C) reduce the velocity differential between the struck vehicle and the occupant kinematic movements, (D) restrain and cushion the occupant's head and torso, or allow contact with energy-absorbing materials to maximize distribution of contact forces.