The Subaru Impreza, WRX, WRX STI, Forester, Legacy, Outback and Baja models all feature heavily reinforced B-pillars. The pillars appear perfectly normal, but their designs and the choices of steel used in manufacturing make them very substantial components for vehicle crashworthiness.
All the metal in the B-pillars is made of high-strength, high-tension steel. Boron is an example of this type of exotic metal. In addition, the individual roof pillars are made from metal pieces of varying thickness called tailored blanks. The B-pillars are cut and welded with a laser, then welded along their edges to form the eight-layer pillar.
The rescuers in the previously mentioned incidents unknowingly attempted to cut the B-pillars at the point where they are intentionally the thickest and the strongest. The round rebar steel rod is only a little over 12 inches long. It begins at dashboard level and ends at almost the height of the roof rail. In this same middle portion of the B-pillar are extra layers of exotic-metal steel – one on the inside surface and another on the outside. They further reinforce and strengthen the pillar.
For other articles about Subaru safety provisions, start a three-part series at Air Bags, Part One.