Stop in for a cup of coffee
Do you know what lamps and bulbs Scott Harvey was refering to in the 1967 Sportscar Graphics rally prep and tips article? Could it be H4 that early?
No. The H4 didn't exist outside of R&D labs until 1969, and then only in Britain. It took a few more years after that to work through the technical approval process for Continental Europe.
Scott Harvey is describing one of the characteristics of the European (now U.N.) low beam light pattern, regardless of what kind of bulb any particular lamp uses: a sharp cutoff line, bright below and dark above, at the top of the beam.
It was a flat, straight-across, symmetrical cutoff for a lot of years, then lighting researchers in the mid-1950s did exhaustive comparisons of U.S. and European lights, to see if maybe the U.S. sealed beam should be adopted in Europe. What they found was that the American low beam gave longer seeing distance down the right side of the road, but also produced more glare than was considered acceptable in Europe with its higher traffic density on narrower roads.
So the industry developed an asymmetrical cutoff: still flat/horizontal on the left side (of each beam), but now slanting upward on the right side (of each beam) to throw more light down the right side of the road while maintaining low glare toward oncoming drivers. The new asymmetrical European beams gave seeing distance roughly equivalent to the American beams, but with the lower glare.
It's kind of pointless to quarrel about beam patterns, though. Both the US and the U.N. headlamp specs allow great headlamps and lousy ones. Also, European practice was (and still is) to aim their headlamps very low, often giving the driver only about a 100-foot preview distance, which is
far too short for anything above about 25 mph. American specs call for higher headlamp aim, giving a longer preview but more glare. For seeing distance a European beam aimed a little higher than intended works about the same as an American beam aimed normally, and an American beam aimed a little lower than intended doesn't produce much more glare than a European beam aimed normally.
The crash-avoidance benefit of higher aim/longer seeing distance is much larger than the crash-risk drawback of lower aim/lower glare, so to a fair degree the American approach is scientifically the more correct one, but it's easy to go too far in either direction. It's too bad we humans are wired to behave as we do; we get dug in on our opinions and they harden into beliefs, which then become something akin to a religion and then both sides are damn sure they're right and the other side's wrong and progress slows to a crawl or grinds to a halt.
For most of a century the Americans have been swearing up and down they're right and the stupid Europeans (and more recently, the stupid rest of the world) is wrong, while the Europeans have been insisting
they're right and the stupid Americans are wrong. Here's the fun(?) part: despite many decades of study all over the world, and despite the clear, significant differences between U.S. and European headlamp light distributions (historically -- not as much now), nobody ever showed an actual safety difference between the two types in terms of crash avoidance or involvement. That's because low beams, by their nature, are not adequate to the task we ask of them, to light our way safely at the speeds we actually drive. The
best low beams, aimed perfectly, are good for going
maybe 45 mph safely. Most of us don't have anything like the best low beams or perfect aim of the low beams we do have.
The solution exists now. It's called "Adaptive Driving Beam" (ADB) or "Glare-Free High Beam". It's a camera- and computer-driven system that tracks other people on the road in front of you and dynamically shadows them out of what is otherwise a full-time high beam. The equipped driver has high-beam seeing, while everyone looking at the car sees, at most, only low-beam glare. It's been on the road for years, giving drivers about a hundred more feet of extra seeing distance with no extra glare in a growing number of models in Europe, Japan, Australia…even Canada (whose regs are usually kept in lockstep with the US rules) got tired of waiting for the American Government and went ahead and said yes on their own.
But it's still not approved in the States. This isn't likely to be fixed any time soon; the American Government in its present form doesn't like any/all regulation, even though a reg doesn't necessarily say "No, you can't"; some of them say "Yes, go ahead". American lighting suppliers have systems developed and on the shelf, just waiting for the U.S. regs to change, but the progress from the relevant agency (NHTSA) has been slow and not very thoughtful. Their latest proposal technically amounted to "OK, automakers, you can put ADB on your cars, as long as it works just like today's ordinary headlamps". The whole industry and safety-research community howled in protest, and NHTSA is now, at least nominally, thinking about what to do next.
Don't nobody hold no breath. :-(
