Rear LED light effectiveness.

wrote:
Driving home last night I overtook a cyclist with what from about 100m
away I thought was a very dim constant rear light. As I overtook him I
saw it was a Cateye LD600 on the chasing mode where each LED lights up
in turn but there is only one LED on at any time. So from the
perspective of a driver this mode would appear to be useless.

This post grabbed my attention because I use an LD600 in chasing mode
(alongside 3 steady rear lamps). It would be interesting to know,
though, whether the mode is generally useless or whether it was just
because the batteries were running low.

A few months ago I asked a colleague to follow me down the hill from the
office to judge the effectiveness of my reflective armbands. I think
that next winter I'll have to ask him to judge the effectiveness of the
LD600 in chasing mode.

--
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"He who dares not offend cannot be honest." - Thomas Paine

On 14 Mar 2006 06:01:48 -0800, wrote:

perspective of a driver this mode would appear to be useless. IE only 1
fifth of the light put out compared to either the constant mode where
all LEDs are lit or the flashing mode where all LEDs flash
simultaneously. Plus from a distance the chasing mode loses the
flashing effect.

I agree. I've seen research that says chasing lights are particlarly
effective. However, I think that any bike light is too small a unit
for the chase to be visible from teh distance at which I want a
motorist to notice me. I use either steady or all-together flash on
my LED lights.

regards, Ian SMith
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On 14 Mar 2006 06:01:48 -0800, "
wrote:

Driving home last night I overtook a cyclist with what from about 100m
away I thought was a very dim constant rear light. As I overtook him I
saw it was a Cateye LD600 on the chasing mode where each LED lights up
in turn but there is only one LED on at any time. So from the
perspective of a driver this mode would appear to be useless. IE only 1
fifth of the light put out compared to either the constant mode where
all LEDs are lit or the flashing mode where all LEDs flash
simultaneously. Plus from a distance the chasing mode loses the
flashing effect.
I use two LD600s on my commuter but don't use the chasing mode anyway.
But it made me wonder whether anyone knew of any side by side
comparisons of LED lights. Given sites like "Your Tube" and Google
Video it would be possible to post video clips of different lights "in
action" so to speak, perhaps side by side comparisons.
As a side issue the cyclist concerned had a poor rear light, no
reflectors and dark clothing. But he was wearing a helmet so
everything would be OK right?

Not knowing what's most effective, I hedge my bets:

On my seat post I have a Cateye TL-LD1000, used in random mode.
http://www.cateye.com/uk/productImag..._LD1000_lg.jpg

Mounted below the rear of my rack I have a Vistalite, used in chaser
mode.
http://www.pricepoint.com/images/sty...5%20VISSN0.jpg

Mounted on my mud guard I have a B&M Seculite Plus, only available in
constant mode.
http://www.bumm.de/docu/grafiken/330alk.jpg
--
Let us have a moment of silence for all Americans who
are now stuck in traffic on their way to a health club
to ride a stationary bicycle. -
Congressman Earl Blumenauer (Oregon)

Ian Smith wrote:
On 14 Mar 2006 06:01:48 -0800, wrote:

perspective of a driver this mode would appear to be useless. IE only 1
fifth of the light put out compared to either the constant mode where
all LEDs are lit or the flashing mode where all LEDs flash
simultaneously. Plus from a distance the chasing mode loses the
flashing effect.

I agree. I've seen research that says chasing lights are particlarly
effective.

What research?

cheers

Jacob

Tom Crispin typed

Not knowing what's most effective, I hedge my bets:

Can't you find a friend to help you ascertain what's most effective?

One person tries some kind of light and rides off. The other stands
behind and watches, and/or gets into a car to observe.

A driver could follow the cyclist and the comment on what's effective
and where.

Cycling in groups will also help you ascertain which of your clubmates
have poor lights.

I've seldom seen a nightAUK with poor lights.

--
Helen D. Vecht:
Edgware.

wrote:
I've made the same point many times i.e. that flashing. flickering or
otherwise intermittent lights are bad news and reduce visibility. This
based mainly on my observation from a drivers point of view, and the
logical argument that less light = less visibility.

But there's no reason to think that a flashing light will have much less
light. If the LED is off half the time, you can drive it twice as hard
for the flashes without overheating it, and keep the same battery life.

The argument that it is harder to judge the position and speed of a
flashing light seems much more convincing.

The naked_draughtsman wrote:

I have a cheapo rear LED light which I use in constant mode. One thing
I've noticed is that with freshly charged batteries, it is very bright
and hurts your eyes to look at it directly.

I used to be a complete advocate for LED rear lights set to flashing mode,
but this was probably because it was in the days before I discovered
retroreflective sticky tape and good capacity rechargeable batteries.
Having also been taking more interest in how I see others on their bikes at
night (cf. Cyclecraft), rather than how I think others see me on my bike,
I've decided that steady LEDs being powered by good batteries are much more
visible and it does seem easier to ascertain their distance.

Mostly I use the Vistalite VL300-series lights, though I have a Cateye LD600
on the trike; the former lasts for ages on a set of batteries and has a
built-in reflector, but the latter is much brighter. I augment the lights
with lots of red reflective tape on static parts of the bike, and amber on
moving parts, and I have a Vistalite Whaletail light set to flashing mode
attached to the top of my lid.

Becky

On Tue, 14 Mar 2006 19:51:53 GMT, Helen Deborah Vecht
wrote:

Tom Crispin typed

Not knowing what's most effective, I hedge my bets:

Can't you find a friend to help you ascertain what's most effective?

One person tries some kind of light and rides off. The other stands
behind and watches, and/or gets into a car to observe.

A driver could follow the cyclist and the comment on what's effective
and where.

Cycling in groups will also help you ascertain which of your clubmates
have poor lights.

I've seldom seen a nightAUK with poor lights.

I don't quite know how to respond to that!

I suppose I don't really want to find out which is most effective 'cos
I like drawing attention to myself and looking like a Christmas tree.
--
Let us have a moment of silence for all Americans who
are now stuck in traffic on their way to a health club
to ride a stationary bicycle. -
Congressman Earl Blumenauer (Oregon)

twisted the electrons to say:
As I overtook him I saw it was a Cateye LD600 on the chasing mode where
each LED lights up in turn but there is only one LED on at any time.

Was it mounted horizontally or vertically? I got an LD600 "free" when I
bought my Streetmachine. My own thoughts when playing around with it was
that horizontal chase mode was liable to be masked by any horizontal
movement of the bike (and thus the light). Hence I tended to mount it
vertically (when I was using the LD600 rather than the TL-AU100BS).
--
These opinions might not even be mine ...
Let alone connected with my employer ...

Alistair Gunn wrote:
twisted the electrons to say:
As I overtook him I saw it was a Cateye LD600 on the chasing mode where
each LED lights up in turn but there is only one LED on at any time.

Was it mounted horizontally or vertically?

It was mounted vertically. I think the battery may have been low as
well but as I said I was surprised by the fact the chasing movement
wasn't apparent until I was very close to the bike.
For what its worth and this is totally unscientific the most
visible rear setip I've ever seen was triple LD600s all in full
flashing mode. The bike I saw had them mounted on the left and right
edges of the rear rack and on the seat tube. As the lights were
flashing at slightly different times it gave a chasing effect but over
the width of the bike hence the chase effect was visible from a
distance unlike the single LD600 I saw.

Iain