Invisible Cyclists in Solstice Dark

"Pat Lamb" wrote in message
...
wrote:

When "twinkling" LED taillights first appeared on the market, they
immediately drew raves because they were so much more visible than
their predecessors, the incandescent taillights. I've never
encountered an instance where they were noticeably _less_ visible.
Have you, or do you have any evidence of such?

Frank,

Since I've been too lazy to try it myself, have you compared the
visibility of a twinkling tail light to a blinking light? My impression,
leaning over the seat and looking down at it, is that the blinking light
is much brighter and likely to attract attention much more than the same
light in twinkling mode.

How about a full regulation police issue set of flashing red and blue
superbright Xenon lights? Mebbe Bob can hook everyone up with a supplier.

The one thing that bugged me from the beginning of this thread:

If the cyclist is invisible does it matter if it is Solstice dark or summer
high noon bright?

*end pedantry zone*

gds wrote:
Pat Lamb wrote:

I'd be happy with a prima facie assumption of liability. Say the car

driver is assumed to be liable for damages, including property, medical,
and lost wages costs, etc., unless the driver can prove otherwise. This
is not a criminal matter, so there's no need for proof beyond a
reasonable doubt, nor is there a presumption of innocence.

Are you serious? You are arguing against the legal assumptions in all
countries using the English common law tradition.

I don't think it's violently opposed to the common law tradition. If
you check, I think you'll find there's a number of places in civil law
where a prima facie assumption exists. It's not automatic; the
presumption can be overcome, but this proposal would shift the starting
position in civil cases.

Your position is more anti motorist than pro cyclist.

A number of regulars on this group remind us that statistically cycling
is not verey dangerous. One can not easily hold that position and still
offer draconian solutions for solving what is argued to be a minor
problem.

It's more like getting the attention of a mule; in this case, the
population of drivers.

Pat

Pat Lamb wrote:
It's more like getting the attention of a mule; in this case, the
population of drivers.

Like I said your suggestion is more anti motorist than pro cyclist.

And probably of no practical value.

Think about how it would play out. First, we need to accept the
statiscal data that there simply are not that many motorist/cyclist
crashes. That has to be the case if the overall cycling serious
accident rate is small as has been presented.

So, if there are relatively a small number of these events then the
economic loss is small in comparison to other types of motoring events.
So, if that is the case the payouts will be relatively small as a % of
total payouts. So, there will be relatively a small impact on rates
which are a reflection of payouts.

If there is a relatively small impact on insurance rates then -I would
argue- there will be a relatively small impact on behavior. And since
it is behavior that we want to change-if you are pro cyclist and not
just anti motorist- you haven't accomplished much.

And if you then argue to move the assumption of guilt to the arena of
criminal action by the motorist you hit a legal wall-as you admit.

Pat Lamb wrote:

Since I've been too lazy to try it myself, have you compared the
visibility of a twinkling tail light to a blinking light? My
impression, leaning over the seat and looking down at it, is that the
blinking light is much brighter and likely to attract attention much
more than the same light in twinkling mode.


Looking at it is the wrong test. Looking (relaxed, not staring)
somewhere and having somebody walk round you from behind at a few yards
distance until you spot the light is the test to do

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

Tony Raven wrote:
wrote:

I'd bet that a bike fitted with 2 otherwise identical lights with one
flashing and the other constant - then if disappearing off on a foggy
night the constant light would remain visible for longer. (if I was a
betting man).


If the problem in hand was seeing how long you could track a bike riding
off into the fog then you are probably right. But that isn't the
problem that needs to be solved. The problem is which light would be
spotted first when the driver probably isn't even looking in its
direction. And the answer is a flashing one every time. Once its
spotted a continuous light is better for tracking its path while
watching it but not for spotting it in the first place. You really
don't seem to have grasped this difference between peripheral vision,
meaning anything outside the area covered by a quarter/10p coin about 6"
from your eye and central vision which is within that area. Judging
lights by looking at them gives you the wrong answers because that is
not the part of your visual system you use for spotting things.
Peripheral vision has poor colour perception, lower resolution, better
light sensitivity, little ability to identify and classify objects but
much better ability to notice movement or fluctuations in the scene.
Its designed to cover a wide field and spot potential threats so that
the brain swivels the central "intelligent" vision part of the eyes
round to identify and classify the threat and take appropriate ignore or
run decisions.


--
Tony

Don't agree. Peripheral vision is not as a important as forward
visibility - since it is only the vehicles forward of the driver in his
direction of travel which he is likely to collide with, except in the
less common circumstance of converging collision courses - (in which
circumstance those spoke attached reflectors are brilliant IMO). Infact
if a driver is distracted by peripheral things such as flickering
lights, is there not a risk that he will collide with things in front?
This is one of my objections to flashing lights - yes they do attract
attention but that they are distracting, even irritating!
I think the foggy night test is extremely relevant to safety since it
is a likely scenario ("the problem to be solved") - and the sooner a
light is seen the better for the driver to take avoiding action. When
I'm cycling a night its always the drivers coming up behind which worry
me most. On a converging course e.g. at a T junction then at least I
can see the car approaching even if he can't see me.

Jacob

"cycle-one" typed

If the cyclist is invisible does it matter if it is Solstice dark or
summer
high noon bright?

So true!

There are more road fatalities in August Daylight than on winter nights.

Cyclists are invisible because they aren't a 'threat'...

--
Helen D. Vecht:
Edgware.

in message , Tony Raven
') wrote:

wrote:

I'd bet that a bike fitted with 2 otherwise identical lights with one
flashing and the other constant - then if disappearing off on a foggy
night the constant light would remain visible for longer. (if I was a
betting man).

If the problem in hand was seeing how long you could track a bike
riding
off into the fog then you are probably right. But that isn't the
problem that needs to be solved. The problem is which light would be
spotted first when the driver probably isn't even looking in its
direction.

In fact the really interesting test would be the reverse of 'owdman's
test. On a foggy night, mount a red light on the /front/ of a bicycle,
and ride it slowly /towards/ an observer until he first notices it. The
observer knows that a bike will come, from roughly (but not exactly)
what direction and roughly (but not exactly) when. As soon as the
observer sees the bike he sings out, the bike stops, and you measure the
distance from the observer to the bike.

Repeat a number of times, sometimes with flashing, sometimes with steady,
sometimes with both. The observer does not know in advance which mode of
lamps will be used on any run. Repeat the whole test, on a clear night,
against a background with a lot of light pollution and visual clutter.

That seems to me an experiment design which is

(i) easy and cheap to set up;
(ii) easy to repeat (and should be repeatable);
(iii) reasonably accurately models visibility of tail lights
to /attentive/ /drivers/;
(iv) potentially publishable;
(v) would potentially give solidly based advice to cyclists and to
regulators.

Anyone setting exercises for an undergraduate engineering design or
psychology class this winter?

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

((DoctorWho)ChristopherEccleston).act();
uk.co.bbc.TypecastException: actor does not want to be typecast.
[adapted from autofile on /., 31/03/05]

wrote:

Don't agree. Peripheral vision is not as a important as forward
visibility - since it is only the vehicles forward of the driver in his
direction of travel which he is likely to collide with, except in the
less common circumstance of converging collision courses - (in which
circumstance those spoke attached reflectors are brilliant IMO).

I suggest you go and sit in your car, get out a quarter/10p coin, hold
it 6" in front of your eye and stare at it. Anything you can see past
the coin is peripheral vision - central vision is an amazingly small
region. You can't even look at the edge of your TV set and recognise
the newsreader it is that small. When you are approaching a cyclist in
traffic they are virtually always in peripheral vision unless you are
looking directly at them.


--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

SMS wrote:

True, but this may be the best you can do with a single light. At least
the varying intensity may help grab attention better than steady-on.


I'd go for two separate lights. Then you have the added advantage that
if one fails or the batteries go flat, the other will mean you are still
lit.

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

SMS wrote:
I'd say that
for the best of both steady and flashing, set the LED tail light to
steady-on, and use a yellow xenon flasher. This would also make you
legal (at least in the U.S.), since technically you're supposed to have
a solid red light, and yellow flashing lights are legal for slow moving
vehicles.

I think you'd better research bicycle lighting laws before making such
pronouncements.

The last I saw (a few years ago) there were only two US states that
required a rear light. See
http://www.massbike.org/bikelaw/bikelawh.htm#ALABAMA, as an example.

The situation may be different in other countries, of course.

- Frank Krygowski