Look at the 2 Mercedes SLs above. You see that they have different headlights. The one on the right is a Euro-spec model that uses attractive composite headlights with replaceable bulbs. The one on the left is a US spec model that has ugly sealed beams. Why would Mercedes put such ugly lights on the cars it sold to Americans? It’s because the government required it for 43 years and put big limitations on styling and aerodynamics.
In 1940, headlights were standardized. The only illumination that cars could offer was from 2 round 7 inch sealed beams, and it was illegal to have those covered with glass. I’ve looked everywhere and I cannot figure why this rule was imposed. The sealed beams were a definite improvement over what came before, they didn’t get any dust or grime inside, but it was absolutely stupid for regulators to assume that headlight technology would not improve.
In 1956, regulators loosened things up a little. Now cars could have 4 headlights that were 5 and ¾ inches, but they still had to be round. The first to take advantage were the 1957 Forward Look Chrysler cars and by 1958, pretty much every car was using them.
One of the ways engineers got around the styling limitations was by having the lights hidden when not in use. This was first done on the 1963 C2 Corvette and would become extremely popular.
The hidden headlight look would show up on Pontiac GTOs, Chevy Camaros, Mercury Cougars, Oldsmobile Toronados, Cadillac Eldorados, and even Plymouth Furies and Chevrolet Caprices. This workaround came with problems however. The moveable covers were just another thing that could break and leave you driving blind. Owners found that in the winter, the covers would freeze over.
And as more European cars found their way over to this country, the limitations became even more apparent, as shown with the title photo Mercedes SL. Perhaps the worst was on the Citroen DS. European models had a very clever system where the headlights would turn with the steering wheel, allowing drivers to see into the bends. This was illegal under US laws, forcing Citroen to delete this clever safety feature on US spec cars.
And by this point, the sealed beams weren’t just unattractive, they were vastly inferior. While Europeans could use then-new halogen lamps which offered a longer life, Americans were stuck with the old Tungsten lamps.
In 1975, the regulation was once again loosened, now headlights could be square. The first to take advantage was the 1975 Cadillac dressed up Chevy Nova Seville. The new rectangular lights set the stage for the next 10 years of boxy American car designs.
The 1977 Dodge Magnum was perhaps the best loophole ever. It needed a more aerodynamic front end for NASCAR racing, but having fixed glass covers over the lights was illegal. So what do they do? They make the clear covers retractable. It was just a reminder of how completely stupid the rule was.
The madness finally ended in 1983 when Ford successfully lobbied the government to allow composite lights with replaceable bulbs. They took advantage with the 1984 Lincoln Mark VII. The lights weren’t just better looking, by being flush with the front end, they improved aerodynamics. Talk about a brighter idea.
35 year later and headlight technology has moved far ahead. First there were bi-xenons, then there were LEDs, now apparently, they’re looking at using lasers. The increased freedom with headlights has been a boon to stylists. Now you can distinguish Audis and BMWs at night thanks to their lights. Just think where we’d be if we still had those sealed beams. I’d say it’d be the dark ages.