Safe Collision Repairs' founder David Williams interviewed auto safety expert, Byron Bloch on August 16, 2007. A portion of his interview questions sought Bloch's opinions regarding aftermarket parts and certifying entity, CAPA. The dialog below features excerpts from this interview. You will be able to read more of Bloch's comments and opinions on other important collision repair topics here on Safe Collision Repairs, and in an upcoming article being prepared for BodyShop Business magazine.

DW: Do you feel that companies like CAPA [Certified Automotive Parts Association] have failed our industry in regard to the fact that they have auto parts tested but, pretty much from a fit standpoint rather than from a structural design standpoint?

BLOCH: You can't just automatically say because a part looks the same and would fit  that it would be a suitable replacement part. If there are dissimilarities geometrically, that's one thing. I'm also saying that metallurgically a part may be of significant difference in terms of, either the kind of stiffness that's needed for side impact and roof crush, or the kind of controlled crush that's needed for front to rear crush zone performance.  And, as to those differences in stiffness, strength, and crushability for sheetmetal parts, I would say, the burden of proving their equivalence to OEM has not been fully demonstrated. An aftermarket part may look like and fit like the original OEM part, but as to performance in crash testing and actual real world collisions there would still be a question mark.

DW: Insurance companies have always taken the position that there are no safety concerns in the [external] sheetmetal of a car. Would you agree with that?

BLOCH: No! I don't agree with that because, for example, the rear quarter panels serve a function in the unitized body where all the sheetmetal panels are welded, spot welded, fillet welded, brazed, gusseted and so on, to work as a unified team. Since all of those panels, gussets, braces, spot welds, fillet welds, and everything has to work together, just simply saying that it may be good for everything underneath the skin but for the skin itself it doesn't make a difference - that's not how the car companies are required to crash test and certify their vehicles. Again, when the vehicle is certified for compliance to the federal safety standards it is an intact vehicle inclusive of all external sheetmetal body parts.