Victor Kan said:
Consider two bike lights like the Cateye EL-500 and the Planet Bike
SuperSpot. Both use 1W Luxeon LEDs and run off 4 AA batteries without
current regulation. Nominally, they should be equally "bright" since
they use the same light and power source. But the EL-500 is more
useful as a bike light, for me anyway, because it lights up the path
in front of you for a decent distance while the SuperSpot, despite its
name, puts out a broad flood over a very short distance with lots of
dark stripes mixed in with bright stripes.It doesn't necessarily take a physicist, but it does take a user who
knows what he actually needs (or I suppose a product designer who
knows what the intended user needs), and useful information about the
shape of the light put out by the lamp, as well as the amount of light
put out by the lamp.
My understanding (correct me if I'm wrong) is that Germany and other
European countries have specifications regarding brightness and beam
shape. IOW, they have standards for the optics, designed so the bike
headlights do a good job of lighting the road and making the cyclist
visible, without blinding anyone.
The US (or, more accurately, the 50 separate-but-United-States) do
not. The typical state law for bike headlights says the light has to
be visible from 500 feet. Period.
So the US gets crude optical technology, with garage mechanics hacking
together lights that spray lumens everywhere, including into oncoming
cyclists' eyes. It's the typical US attitude: "More is better,
intelligence is for wimps, and if my equipment bothers you, go #%*!
yourself."
It's the same as the US attitude toward SUVs, McMansions, sound
systems, boomer cars, and conspicuous consumption in general.
And like many of those, it's "justified" by irrational fear. "Hey,
I'm using the Hummer to drop my little princess off at the school
door. If I don't, someone driving a mere Explorer might run her
over!"
- Frank Krygowski