Maybe Joan Claybrook or William Haddon can answer the question. They were running DOT 30 years ago. All they cared about was their personal agenda, which was airbags.

Sealed beam technology was the hot setup back in the 30s and became one of the few federal vehicle regulatory requirements.

The Europeans began to develop and phase in better optics in the fifties, but we remained stuck in the 30s until the late eighties.

Look at the tire fiasco. US minimum performance standards for tires haven't changed since the late sixties. Take marginal standards, add poor manufacturing, and you have tread separations.

US and European lighting codes still have different beam pattern requirements. Both need to get together and come up with a common standard, but don't expect regulatory requirements to make sense or keep up with technology when you have lawyers running the regulatory agencies.

Duke