On 2/25/2018 10:59 AM, sms wrote:

- Frank's main concern is that the light work off a dynamo. All his
other statements are rationalizations of why it is not necessary to
illuminate anything other than the pavement immediately in front of a
rather slow-moving rider. He understands, but does not want to admit,
the importance of proper optics on LED lights in order to illuminate not
only the patch of pavement directly in front of the tire.

It's true that I greatly prefer dynamo lights, so I don't have to fuss
about recharging or replacing batteries - SMS recently noted that even
rechargeable batteries may soon need replacement. I want my bikes to be
always ready to properly light the way for safe riding in the dark.

That means much more than "the patch of pavement directly in front of
the tire." I have at least two B&M dynamo headlights that show a stop
sign up to 1/4 mile away. They light the roadway far enough ahead for
riding well over 20 mph. In my experience, it was the LED flashlights
SMS advertised that were limited to a patch of pavement.

- I want both side spill and upward spill. But of course you can do this
without blinding oncoming motorists, which is a red-herring anyway since
on even a two lane road, with the cyclist on the right (or on the left
in countries where they drive on the wrong side of the road), a motorist
coming the other way will not be blinded. The real concern is that on a
narrow MUP that oncoming cyclists not be blinded.

I have been blinded while riding at night more than once by oncoming
*kilo-lumen cyclists on full-width two lane roads. I've had it on bike
trails, too, even though I don't spend much time on bike trails.

In fact, I even had trouble once with a rider's kilo-lumen light while I
was driving in daytime. It was a female cyclist on a rural highway. She
was apparently a victim of extreme "fear from the rear." She had a
hugely bright headlight mounted on her bike's rear rack, facing
backward. I changed lanes to pass, as I would have anyway; but I had to
shield my eyes as I did so.

White lights facing rear on bicycles violate state law. Not that it
matters to people like that.

(* I guess I should use kilo-lumen instead of mega-lumen. The latter
probably won't be available for a year or two.)

--
- Frank Krygowski