headlight recommend?

DougC said:

(PeteCresswell) said:

...
I'm confused by a lot of headlight discussions.  It's as if the
headlight were the most important factor in being seen.   Seems
to me like what's on the back of the bike is more important by
far. ....

This is true--that some people argue it, and that it is (for the most
part) misguided.

If you're riding with traffic, a motor vehicle will not see your
headlight much at all until they pass you. Any cars that are oncoming
are supposed to be on the opposite side of the road anyway.

As for cars approaching on perpendicular streets, that's easy--you slow
down and let the car go first, or at least slow down enough to see what
it's going to do.

The only way to know the driver saw you would take a fantastically
bright enough light that you could see inside the car from a distance
and make eye contact--and that much light would certainly blind the driver..

But the simpler reason for letting the car go ahead is that if you and
the car BOTH try to cross the same point, the car may get some scratches
but you on a bicycle are likely to suffer much worse, and after the fact
a $1000 bicycle light won't mitigate the damage. A bigger light does not
make your bicycle a bigger vehicle, and you're safer keeping that in mind.
~

I agree, and wish that some of the cyclists around here would keep
some of your points in mind.

My main purpose for researching headlights etc. is not so that others
see me. I figure anything white and glowing on the handlebars will
accomplish that. I just want the ability to ride on unlit streets or
trails should I choose to do so, so I'm possibly looking for a little
more light than your average urban-only commuter.

nate

Chalo said:

http://www.dealextreme.com/details.dx/sku.1919

It's a drop-in replacement for the Task Force light's optic, and it
casts a wide "stripe" beam a lot like a car headlight.

Chalo

Thanks for the tip! I think I'll give these a try.

Have you tried the combo yourself? With the stock optic, I find the
beam is just shy of wide enough to cover one narrow lane and good
enough to penetrate through other lighting I encounter (be it oncoming
headlights or overhead street lighting that leaves dark patches
between lamps). Having the same amount of light squashed to be
flatter (but not much "shorter"😉 and wider sounds like just what I'd
want.

"DougC" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Yes, but if you had bought a Peter White bike and otherwise fitted it out
"suitably", then your $2000 headlights would still only cost 20-25% as
much as you spent on the rest of the bike.

I'd guess in P. White's mind, a $2000 light does not seem unreasonable.
After all, he can't be advising customers to hang a chintzy $50 piece of
glow-in-the-dark plastic on the bars....
~

$50 USD?! These guys have a very nice Glow in the Dark Jesus, and it does
not cost anywhere near $50:

http://www.findgift.com/gift-ideas/pid-14838/

Just get a roll of duct tape and you are all set.

J.

In article
<[email hidden]>,

Chalo said:

Burning virgin veggie oil means choosing to feed a car instead of a
bunch of people.

This is going to be one of the ethical dilemmas of the 21st century.
What's more important- driving 38 miles one way to work using a
bio-fuel, or not raising food prices to the extent that millions more
people starve?

Ride bike!

Chalo said:

Waste veggie oil as fuel constitutes a pretty good use of resources,
but that stuff would otherwise become soap or something, not just get
thrown away. Burning virgin veggie oil means choosing to feed a car
instead of a bunch of people.

My friend uses waste oil from restaurants. He finds that the best oil
comes from Japanese-owned, Japanese restaurants, because they change
their fryer oil very often. Oil from Chinese restaurants is not as good
because they use it a lot longer prior to dumping it.

The restaurants used to pay to have the old oil hauled away. Now they
get rid of it for free. Soon they'll start charging for it I imagine.
The city of San Francisco wants to use the old oil for their diesel
buses, which will probably eliminate the free supply to individuals.

Jay said:

"DougC" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Yes, but if you had bought a Peter White bike and otherwise fitted it out
"suitably", then your $2000 headlights would still only cost 20-25% as
much as you spent on the rest of the bike.

I'd guess in P. White's mind, a $2000 light does not seem unreasonable.
After all, he can't be advising customers to hang a chintzy $50 piece of
glow-in-the-dark plastic on the bars....
~

$50 USD?! These guys have a very nice Glow in the Dark Jesus, and it does
not cost anywhere near $50:

http://www.findgift.com/gift-ideas/pid-14838/

That glows in the dark after being exposed to light, but what you need
is an internally lit Jesus, such as
"http://www.skyfireproducts.com/servlet/the-1965/Frosted-Jesus-with-Led/Detail"

I contacted them about doing a Cree edition of this product for
cyclists, but they said that it would melt the product.

Nate Nagel said:

Chalo said:

N8N wrote:

Quoted message said:

Quoted message said:

I mean, the concept of having enough light
output to fry flies makes me giggle, but I honestly don't want to
inadvertantly blind oncoming motorists...

Quoted message said:

Yeah, you'd have to blind them, deafen them, fog them with poison gas,
and run them off the road to fully return the favors they do for us.

Quoted message said:

Chalo

From a motorist's perspective, I'm not a big fan of cyclists. I call
the cyclists that I see from behind the wheel "suicyclists" because I
assume from their behavior...

Examples?

Quoted message said:

... that they have a death wish. I have no
desire to start yet another interminable RAD/rec.bicycles.whatever flame
war, but let's just agree that there's plenty of stupid...

It's plenty stupid to assume that taking any risk (even a stupid one)
implies a death wish.

Quoted message said:

... on both sides.

From up and down, and still somehow... :-)

DougC said:

(PeteCresswell) said:

...
I'm confused by a lot of headlight discussions. It's as if the
headlight were the most important factor in being seen. Seems
to me like what's on the back of the bike is more important by
far. ....

This is true--that some people argue it, and that it is (for the most
part) misguided.

If you're riding with traffic, a motor vehicle will not see your
headlight much at all until they pass you. Any cars that are oncoming
are supposed to be on the opposite side of the road anyway.

As for cars approaching on perpendicular streets, that's easy--you slow
down and let the car go first, or at least slow down enough to see what
it's going to do.

The only way to know the driver saw you would take a fantastically
bright enough light that you could see inside the car from a distance
and make eye contact--and that much light would certainly blind the driver.

But the simpler reason for letting the car go ahead is that if you and
the car BOTH try to cross the same point, the car may get some scratches
but you on a bicycle are likely to suffer much worse, and after the fact
a $1000 bicycle light won't mitigate the damage. A bigger light does not
make your bicycle a bigger vehicle, and you're safer keeping that in mind.

I see there's a lot of fear of the dark, and fear of traffic, out
there!

I do a lot of night utility riding, and my commuting route often has
me riding at night. Perhaps three miles of it are on a residential
collector street that has many cross streets, where I have the right
of way and they have stop signs. It's _very_ common for motorists to
have to wait for me.

If I want to know the motorist has seen me, I can shake my handlebar
quickly to the side, then back straight. That flashes the headlight
at them. I do it sometimes (typically, for someone driving fast up to
their stop sign). But whether I do or not, in all the hundreds of
times that situation has arisen, I've _never_ had a motorist pull out
dangerously in front of me. Likewise, I've never had an oncoming left-
turn motorist endanger me by cutting across my path. In fact, it's
not uncommon for both types of motorists to wait an extremely long
time for me to pass, when they could have safely proceeded. And BTW,
this is using a pretty standard generator headlight.

To stop and let every motorist go first, as suggested above, is
paranoid and unnecessary. It's an extreme reaction to an irrational
fear.

Take your bike and its headlight out at night, with a friend. Have
him ride it while you observe. If you think your headlight isn't
conspicuous enough, feel free to upgrade. But unless you're using one
of those nickel-sized keychain LED lights, your headlight is probably
fine for being seen. That's been the case with everyone that I've
ever tested this with.

In particular, if your headlight shows you the road surface well
enough, you can be sure it's very noticeable to motorists. And you
shouldn't be riding if you can't see the road surface.

- Frank Krygowski

Victor Kan said:

Chalo said:

http://www.dealextreme.com/details.dx/sku.1919

It's a drop-in replacement for the Task Force light's optic, and it
casts a wide "stripe" beam a lot like a car headlight.

Thanks for the tip! I think I'll give these a try.

Have you tried the combo yourself? With the stock optic, I find the
beam is just shy of wide enough to cover one narrow lane and good
enough to penetrate through other lighting I encounter (be it oncoming
headlights or overhead street lighting that leaves dark patches
between lamps). Having the same amount of light squashed to be
flatter (but not much "shorter"😉 and wider sounds like just what I'd
want.

I've bought a pack of these optics and converted one of my Task Force
lights. The beam peak intensity is much diminished, as the small
hotspot is spread across a flood-like angle (but only in the one
axis). Spill above and below the stripe looks pretty similar to the
previous intensity-- not much, but enough for a be-seen light. I like
this beam shape even for looking around in the backyard. Spreading
the bright portion of the beam sideways across the ground means less
wagging around trying to put the hotspot where I am looking.

Chalo

Chalo said:

Frank Krygowski said:

FWIW, I absolutely hate having a cyclist with that [blinding] mindset coming at
me when I'm riding my bike. It's bad on a road, especially a narrow
one. The couple times I've had it happen on a bike path, it was
terrible. I imagine it's also very annoying to pedestrians.

I have been dazzled by bike HID lights, but even the brightest LED
lights are less intense than car headlights and streetlights. They
are not more annoying than anybody else's lights. When I cross into a
section of lakeside trail, I switch from full power strobe to low
power steady beam to go easy on dark-adjusted cyclist and ped eyes.

Quoted message said:

Folks, the fact of the matter is, you don't NEED to blind motorists to
be perfectly conspicuous.

You mean "obvious", and that presumes that a driver is even bothering
to look for you. Turn it up to "irritating", and a driver need not be
looking for you to notice you anyway.

If it's irritating to a motorist, it's irritating to a bicyclist and
to a pedestrian. It may be debilitating to a bicyclist on a narrow
street or path. And there's just no need to be that irritating!

There's too much fear of the dark. Look, I'll admit that cycling in
the dark can be more dangerous - but in almost all cases, the danger
comes from complete lack of lights, not from having lights that are
dim but legal.

In a few cases, people may have falls caused by not spotting gravel,
potholes, etc. because of using dim "be seen" lights where there's no
street lighting. I saw that risk way back when I first started night
riding, using Cateye battery lights with two C cells and a 1 watt
vacuum bulb.

But we're talking about unseen road hazards. We're talking about fear
of motorists. And I believe any dispassionate observation of a decent
bike headlight in traffic will show it's fine. That's been the case
every time I've tested this with any other rider - and I've done it
many times.

Quoted message said:

Quoted message said:

If a light with proper optics is
aimed so it illuminates the road sufficiently, there will be plenty of
"spill" light that goes directly to the retina of anyone who needs to
see you.

Ummm, no. There are too many other light sources near and far in the
central city to depend on one small steady light to announce your
presence in time. Drivers have no consensus about how fast to drive
on city streets around here, and distances close quickly at a relative
50mph or more.

Try it, Chalo. Set up a "Night Lighting Workshop." That's what I
called mine. Even my most safety-fixated friend (the one who used to
lobby for mandatory helmets) said "Wow. I had no idea how my
headlight stood out. I didn't need to be worried," or words to that
effect.

You can also observe other cyclists riding around the city or
suburbs. IME, even the small be-seen LED lights (way weaker than Cree
units) show up in plenty of time.

Quoted message said:

Quoted message said:

The lumens that make you conspicuous go directly from
your lamp to someone else's retinas. They don't get partially
absorbed by any road surface. They do NOT need to be as intense as
the road lighting.

You keep saying "conspicuous" when what you mean is "visible". And
merely being visible only works when someone is _trying_ to see you.
On some streets, that's plenty. On others, it would be better to be
mistaken for a police car.

Whether you call it "conspicuous" or "visible," I mean enough of it to
prevent being hit. I mean as noticeable at night as I am in daylight
- which is obviously enough, or I wouldn't ride in daylight!

I'm sure there are streets that are worse than others, but I've never
seen a street where my generator headlight wouldn't do well. What
would that situation be? Traffic from behind sees my taillights and
reflectors instead of my headlight. Oncoming left-turning traffic is
probably the harshest test, but it's a test that my lights have passed
hundreds of times. And those motorists _are_ trying to see oncoming
traffic, to be sure they won't get hit head on.

Let me invent a situation where my good generator light might be
inadequate: If I had a long, very steep (30+mph) downhill on a busy
four-lane-plus-center-turn-lane arterial, with lots of oncoming left
turners trying to squeeze through gaps in traffic, I'd worry. I've
not observed my headlights in that specific situation. But that
combination of very high bike speed, competing traffic and impatient
left turners isn't part of my world - nor part of most cyclists'
worlds.

Freeway interchanges, five-lane arterials with 35000+ cars per day,
potholed roads, dark residential streets, country roads - all these
are part of my world. I've ridden them all and never needed to blind
anyone.

Quoted message said:

Quoted message said:

Don't fall into the fallacy that cycling is so dangerous that you need
extreme measures to survive.

Three hit & runs on four peds (two fatalities) in the last week in
central Austin. Another attempt to leave the scene by a driver who
hit a pedicab and injured the passengers. And that's just the ones
reported to me by my personal friends.

Walking near traffic can be dangerous, I'll grant you that. It's been
shown to be significantly more dangerous than bicycling.

But what you need, to make your case, is 1) accounts of motorists
hitting cyclists who were using headlights of ordinary power, because
they didn't notice the cyclists despite the lights. Frankly, I've
never read such an account. Has anyone else?

2) Alternately, if while driving, you've had a near miss with a
cyclist you didn't see because of active, but inadequate lighting,
that would at least be some anecdotal evidence. But I've never had a
driving near-miss with even an unlit cyclist. Has anyone else?

By my deliberate tests with fellow club members, and by my years of
biking and driving experience, I've concluded that you don't need
super headlights to be adequately conspicuous (or visible, or
whatever). If people have stories to tell that illustrate #1 or #2,
let's hear them.

(Real data would be much better, of course, but I've searched pretty
hard for several years, yet found nothing.)

- Frank Krygowski

Dan O said:

Nate Nagel said:

Chalo said:

N8N wrote:

Quoted message said:

Quoted message said:

>I mean, the concept of having enough light
>output to fry flies makes me giggle, but I honestly don't want to
>inadvertantly blind oncoming motorists...

Quoted message said:

Quoted message said:

Yeah, you'd have to blind them, deafen them, fog them with poison gas,
and run them off the road to fully return the favors they do for us.

Quoted message said:

Quoted message said:

Chalo

Quoted message said:

From a motorist's perspective, I'm not a big fan of cyclists.  I call
the cyclists that I see from behind the wheel "suicyclists" because I
assume from their behavior...

Examples?

*consistently* blowing stop signs in front of me, when by conventional
rules of traffic I have the right of way. Gutter passing approaching
stop signs/lights when there is right turning traffic. Riding at
night against traffic with no lights. My morning commute takes me
along a route where the W&OD trail is discontinuous and takes to
regular streets for a couple blocks; cyclists in that area seem to
think that they have automatic right of way since it's signed as a
bike trail. (never mind that it intersects the road that goes right
by the Metro station, so there's a lot of vehicular traffic as well.)

Quoted message said:

Quoted message said:

... that they have a death wish.  I have no
desire to start yet another interminable RAD/rec.bicycles.whatever flame
war, but let's just agree that there's plenty of stupid...

It's plenty stupid to assume that taking any risk (even a stupid one)
implies a death wish.

I'm not saying they *do* have a death wish, but they certainly act
like they do.

Quoted message said:

Quoted message said:

... on both sides.

From up and down, and still somehow... :-)

yeah, drivers around here suck too. They make me shake my head even
from behind the wheel.

nate

In article <[email hidden]>, Tim

McNamara said:

In article
<[email hidden]>,

Chalo said:

Burning virgin veggie oil means choosing to feed a car instead of a
bunch of people.

This is going to be one of the ethical dilemmas of the 21st century.
What's more important- driving 38 miles one way to work using a
bio-fuel, or not raising food prices to the extent that millions more
people starve?

Ride bike!

Only an ethical dilemma if we foolishly persist in placing such great
distances between our workplaces, homes and amenities. We've only
had...oh, 35 years or so, that is, since the first energy crisis, to
get serious about the problem.

But it's so much easier to forget about it, hop in the SUV and head to
the mall...

Luke said:

In article <[email hidden]>, Tim

McNamara said:

In article
<[email hidden]>,
 Chalo <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Burning virgin veggie oil means choosing to feed a car instead of a
bunch of people.

Quoted message said:

This is going to be one of the ethical dilemmas of the 21st century.  
What's more important- driving 38 miles one way to work using a
bio-fuel, or not raising food prices to the extent that millions more
people starve?

Quoted message said:

Ride bike!

Only an ethical dilemma if we foolishly persist in placing such great
distances between our workplaces, homes and amenities. We've only
had...oh, 35 years or so, that is, since the first energy crisis, to
get serious about the problem.

But it's so much easier to forget about it, hop in the SUV and head to
the mall...

It's a self-solving problem, economically, if we DON'T actively try to
suppress the continued rise in fuel prices. Employers will move their
offices closer to the areas where most of their employees are
concentrated, and those outliers will either pay for the privilege of
living farther away or else move as well.

The downside is, of course, recession and the fact that poorer people
will be harder hit as fuel use (and rising costs of consumer goods due
to higher fuel prices) will make up a higher percentage of their
income. This could conceivably be combatted by making our tax system
more progressive, although that would be quite unpopular. And it's
still going to hurt everyone, but I don't see a better alternative.
This is the only way that we will get real, useful renewable energy
sources developed - no amount of legislating or policymaking can
accomplish this, as our government seems to be more interested in
appearing to do something than actually accomplishing something
useful.

I'm especially disappointed in McCain and Hillary for supporting the
gas tax holiday; that's got to be one of the worst ideas I've ever
heard. If they were smart they'd do nothing, as the desired goal is
higher fuel costs, and it's happening *without* a tax increase, so it
can't be directly blamed on legislators. It's a gift and they don't
even realize it. And I've heard more economically savvy people than I
state that their prediction is that the main consequence of the gas
tax holiday would be decreased revenue to the government *without* the
relief in gas prices that the measure would be intended to cause
because of limited supply.

nate

N8N said:

And I've heard more economically savvy people than I
state that their prediction is that the main consequence of the gas
tax holiday would be decreased revenue to the government *without* the
relief in gas prices that the measure would be intended to cause
because of limited supply.

That's exactly what will happen. The retail price of gasoline, inclusive
of taxes, is being set to the highest price the market will bear. A cut
in the gasoline tax will result in a price reduction of very short
duration. We also saw the opposite occur in California a while back
where a 10 cent increase in the gasoline tax resulted in very a
short-lived 10 cent spike in the retail price, before the price fell
back to where it was before, with 10 cents less for the refinery, and 10
cents more for the government.

If McCain and Clinton want to help the oil companies make more money,
then cut the gas tax. Perot had the right idea with a 50 cent gas tax,
but he was such a nut job no one took him seriously.

In article
<[email hidden]>, N8N

Quoted message said:

Luke said:

In article <[email hidden]>, Tim

McNamara said:

In article
<[email hidden]>,
 Chalo <[email hidden]> wrote:

Quoted message said:

> Burning virgin veggie oil means choosing to feed a car instead of a
> bunch of people.

Quoted message said:

This is going to be one of the ethical dilemmas of the 21st century.  
What's more important- driving 38 miles one way to work using a
bio-fuel, or not raising food prices to the extent that millions more
people starve?

Quoted message said:

Ride bike!

Only an ethical dilemma if we foolishly persist in placing such great
distances between our workplaces, homes and amenities. We've only
had...oh, 35 years or so, that is, since the first energy crisis, to
get serious about the problem.

But it's so much easier to forget about it, hop in the SUV and head to
the mall...

It's a self-solving problem, economically, if we DON'T actively try to
suppress the continued rise in fuel prices. Employers will move their
offices closer to the areas where most of their employees are
concentrated, and those outliers will either pay for the privilege of
living farther away or else move as well.

While true, I suspect that the process may not be so orderly or
confined as your assertion implies. New economic networks will be
created, others destroyed, lifestyles and expectations will require
much revision; this will involve much more than a reshuffling of
employers and employees. Expect a drastic update of the American Dream.

Quoted message said:

The downside is, of course, recession and the fact that poorer people
will be harder hit as fuel use (and rising costs of consumer goods due
to higher fuel prices) will make up a higher percentage of their
income. This could conceivably be combatted by making our tax system
more progressive, although that would be quite unpopular. And it's
still going to hurt everyone, but I don't see a better alternative.
This is the only way that we will get real, useful renewable energy
sources developed - no amount of legislating or policymaking can
accomplish this, as our government seems to be more interested in
appearing to do something than actually accomplishing something
useful.

Indeed. Mention in the U.S. what the rest of the industrialized word
accepts as beneficial, i.e., high gas taxes, and the hordes are ready
to take to the barricades. But as you've noted the economics of supply
and demand ratcheting up the price of crude will obviate the need of
punitive taxes aimed at curtailing consumption. Now there is no choice
but to conserve, realize efficiencies and seek out alternate energy
sources.

Quoted message said:

I'm especially disappointed in McCain and Hillary for supporting the
gas tax holiday; that's got to be one of the worst ideas I've ever
heard.

I absolutely agree. This holiday will only serve to stimulate demand --
talk about regressive policy.

But the proposal is indicative of how political pandering plays into a
prevailing perspective that is *heavily* vested in the status quo. Do
folks realize that confronting the problem, rather than taking a
holiday from it, is the only route to a solution? This problem isn't
going away, it'll be here when ya get back from Disney World. And North
America, by and large, *has been* on holiday from the impending reality
for the last generation; the last thing that's needed is more time off.

Quoted message said:

If they were smart they'd do nothing, as the desired goal is
higher fuel costs, and it's happening *without* a tax increase, so it
can't be directly blamed on legislators. It's a gift and they don't
even realize it. And I've heard more economically savvy people than I
state that their prediction is that the main consequence of the gas
tax holiday would be decreased revenue to the government *without* the
relief in gas prices that the measure would be intended to cause
because of limited supply.

nate

The price of crude in May 2003 was ~$25 per barrel, five years on it's
increased more than four-fold. A gas tax holiday significantly
affecting this trend would bankrupt the nation. There's no need to
repeat the exercise: fiscal mismanagement and the Iraq war are already
doing a nice job of it as it is.

SMS said:

N8N said:

And I've heard more economically savvy people than I
state that their prediction is that the main consequence of the gas
tax holiday would be decreased revenue to the government *without* the
relief in gas prices that the measure would be intended to cause
because of limited supply.

That's exactly what will happen. The retail price of gasoline, inclusive
of taxes, is being set to the highest price the market will bear. A cut
in the gasoline tax will result in a price reduction of very short
duration. We also saw the opposite occur in California a while back
where a 10 cent increase in the gasoline tax resulted in very a
short-lived 10 cent spike in the retail price, before the price fell
back to where it was before, with 10 cents less for the refinery, and 10
cents more for the government.

If McCain and Clinton want to help the oil companies make more money,
then cut the gas tax. Perot had the right idea with a 50 cent gas tax,
but he was such a nut job no one took him seriously.

The 50 cent tax was John Anderson's idea (3rd party candidate for Pres
in 1980, against Reagan and Carter) - back when gasoline in the U.S. was
around a dollar a gallon, so 50 cents was "a lot". Did Perot repeat the
idea? If so, I missed it.

Mark J.

Why can't they standardize the way these things were rated? This
headlight has a 32 watt bulb, that one gives 3400 max candlepower, yet
another has 4500 lumens of light.

So which one is brightest? I don't know, go ask a physicist, stupid!

- -
Compliments of:
"Your Friendly Neighborhood Wheelman"

If you want to E-mail me use:
ChrisZCorner "at" webtv "dot" net

My website:
http://geocities.com/czcorner

landotter said:

(PeteCresswell) said:

Per Nate Nagel:

Quoted message said:

Am I silly in thinking I ought to be able to find something "acceptable"
for less? or should I suck it up and buy it? Can anyone recommend any
products in particular?

Lowe's "Task Force" flashlight - the one that takes 2 C cells and
contains a Cree 4w emitter. http://tinyurl.com/4ev9ly

About thirty bucks.

Costco has a similar flashlight with the same emitter, also cheap with
a nice alu case. Should be easy to mod a mount for it.

The problem with the Costco (Leatherman Monarch 500) Cree emitter
flashlight is that it runs off three AAA batteries, rather the two C
batteries. You can get two 5500 mAH NiMH C batteries, for 2.4V x 5.5AH =
13.2WH. You can get three 1000 mAH NiMH AAA cells for 3.6V x 1 AH
=3.6WH. That's a very big difference in operating time.

The Costco flashlight is better in some ways, as it's better
constructed, and it has an adjustable beam.

You can see more info about it at
"http://www.candlepowerforums.com/vb/showthread.php?t=182032"

Chalo said:

You keep saying "conspicuous" when what you mean is "visible". And
merely being visible only works when someone is _trying_ to see you.
On some streets, that's plenty. On others, it would be better to be
mistaken for a police car.

That's a key point that some people don't understand. Telling someone to
look at your bicycle while your riding at night, and having them tell
you whether they notice you or not, is ludicrous by definition. You need
to be visible when people _aren't_ trying to see you. Of all the
ridiculous justifications that people use for not having adequate
lighting, 'I asked someone to look at for bicycle at night and they said
they could see me, and that proves my lights are fine' has got to be the
dumbest.

Quoted message said:

By "at night", I think you mean "in darkness". Downtown at night is
not a good place to be made conspicuous by a feeble light turned down
towards the road. The street lighting alone will do at least that
much for you.

I do quite a bit of night riding in downtown-like areas with street
lights and a lot of traffic lights and other distracting lights from
stores, etc. You may as well turn off a low power light, whether it's a
dynamo or a battery powered, because it won't do anything for you for
either seeing or being seen. You can either use a more powerful light,
or use some sort of white strobe light.

Quoted message said:

Three hit & runs on four peds (two fatalities) in the last week in
central Austin. Another attempt to leave the scene by a driver who
hit a pedicab and injured the passengers. And that's just the ones
reported to me by my personal friends.

Sadly, there's been a lot of fatalities around the Bay Area in the past
month or so. Two killed by an idiot sheriff's deputy, three school kids,
a 40 year old killed by a quarry truck in Santa Cruz. While cycling home
from the grocery store today, I ran into someone (not literally) whose
husband had been killed by a quarry truck quite a few years ago on the
same road where the sheriff's deputy killed the two cyclists.

(It's Chris) said:

Why can't they standardize the way these things were rated? This
headlight has a 32 watt bulb, that one gives 3400 max candlepower, yet
another has 4500 lumens of light.

Even if they did, a single number doesn't tell you everything you need
to know.

Quoted message said:

So which one is brightest? I don't know, go ask a physicist, stupid!

Brightest for what? Brightest tiny spot for super long distance use?
Or brightest flood for lighting up nearby environs? Or something in
between?

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.