At 10:19 AM 12/4/2012, meekerdb wrote:
The US auto lighting regulations also discouraged "non sealed beam" headlights, which completely stalled vehicle lighting innovation for 30-40 years.
I don't think so. The standard was adopted to get rid of the bulb and unsealed reflector lights which were common before WW2. Their problem was that the reflector would get dirty from condensation and even corrode. Motorcycle headlights were never required to be sealed beams (because it's easy to carry a spare bulb, but not a whole headlight) but there was no great innovation or superiority in motorcycle lights.
I don't want to start a flame war, but in the 1970's the US car companies were getting their lunch eaten by the foreign car companies. Honda embarrassed the c**p out of GM in the early 1971 by showing US Congress a Chevy Vega whose cylinder heads had been replaced with Honda's CVCC technology, and thereby met 1975 smog standards at very low cost. Congress retaliated with increased trade barriers (including some of these headlight issues), as well as a several year delay in the 1976 smog standards. The following U.S. report to Congress was basically a "Pearl Harbor" moment for the US auto companies. 1973. Report by the Committee on Motor Vehicle Emissions. Board on Environmental Studies and Toxicology. "3.9.3. ... In February 1971, emissions data with this [Honda CVCC] system on engine dynamometer tests indicated the [CVCC] engine could meet 1975 standards; the first successful car test that met the standards was in Spring 1972. In addition to developing a 2-liter, 4-cylinder engine for their own vehicle, Honda has applied the same techniques to modify two Chevrolet Vega 4-cylinder engines. ... All these cars met the 1975 standards without EGR or exhaust [e.g., catalytic converter] treatment, and Honda has expressed confidence that larger engines using the CVCC approach could also be made to meet 1975 standards without a catalyst. ..." "The effects on vehicle performance of the CVCC system are small. ... Fuel economy is essentially unchanged. There are no driveability problems." See also Table 3-11 which compared the Honda cars with 1 original Vega and 2 modified Vegas. --- The dirty/corroded headlight reflector problem had certainly been a problem in the 1940's, but by the 1970's, replaceable bulb headlights were in extensive use around the world outside the U.S. European headlight systems has to be _downgraded_ in the 1970's in order for European cars to be imported into the US. Ask any German who drove the Autobahns in the 1970's and 1980's, and who had also driven US cars on US freeways.