Interesting Pacifica feature

I saw this for the first time on a police cruiser the other day. What caught
my eye was the intense deep blue light. Certainly very attention grabbing
(at least to me). It is so much brighter than the blue filtered incandescent
light.
John

 

Your loss...

 

It is so refreshing to see evidence of intelligent life on this
planet. Thank you.

 

On Sat, 3 Jan 2004, Ted Mittelstaedt wrote:

[paraphrased from a couple of posts: Center high mount brake lights only
worked temporarily because of the novelty effect, and once all cars have
them, a similar effect would be found by releasing new cars without them]

Aye caramba. Not this old canard again. This myth borders on a conspiracy
theory, and with folks like Ted spouting it again and again and again like
a broken record, it refuses to die.

The Center High Mount Stop Light *per se* works. As with all conspicuity
devices (sidemarker lights, sidemarker reflectors, etc.) , the degree to
which it worked was initially higher due to the novelty effect before
settling to a lower but still significant degree of benefit.

URLs for various studies and cost-benefit analyses have been posted in
these forums many times, quite recently. And when you look at the number
of countries in which CHMSLs have been mandated over the last 15 years,
and realise that each one of those countries did its own cost-benefit
analysis and study before consenting, well, it just makes you look even
more ignert than you already do for spouting on about novelty effects.

DS

 

You need to look up the definition of these two words. Hint: they
aren't synonymous.


Matt

 

Hint: I never said they were synonymous. Please read the rest of the
thread.

 

Not really..............

 

|
| Gee, whiz, I guess we better hurry and remove the strobes from all those
| emergency vehicles pronto! Who knows, the mass population-wide epileptic
| seizure attack could be just around the corner! Think of the disaster we
| could avert! Write Congress!!!

Good idea!

|
| --Geoff
| (f*** the strobes, I want "attack lasers" behind my grille...)
|
|

 

Maryland state police use LED lights on their vehicles, even their
un-marked cruisers. and, they use a *lot* of lights on their marked
vehicles.

earlier today I was on a highway, and saw their LED flashers a half-mile
back in my mirrors. they shot past me at over 100mph and could see
their lights for at least a mile.

when they passed, the lights were extremely bright. brighter than any
standard lights I see in Delaware. tonight, I passed an unmarked car
with LEDs on a shoulder (writing a ticket). they were bright, but not
blindingly so.

 

I sure have no reason to doubt that based on what I've seen, though to be fair
there are a few types of LED flashers that aren't up to par (and some
standard-round LED semi taillights are too bright and too point-source as well,
but I digress). The Dane County Sheriff's Department has some on its breakdown
truck that are rather ineffectual--like a fixed flasher unit you'd see on the
corners of an ambulance, just below the roofline, but divided into four separate
red/blue sections, two each side that flash alternately to one anther. Each
section is too damn small and not bright enough. by _any_ reasonable appraisal.
Though this may be a limitation due to conceptual flaws rather than the LEDs used
themselves. And AFAIK I don't see them being listed by anyone anymore either,
they might be a year or two old and now discontinued.

--Aardwolf.

 

Dan, some of that was exaggeration to be funny - don't think that I
seriously
was suggesting that removing the CHMSL would help with rear end collisions.

Ah, you at least are admitting that. However I disagree that there is any
significant degree of benefit.

Hmm this is from the person who says that the US is preventing Canada from
mandating amber turn signals? Why does every country have perfect control
over consenting to CHMSL's yet Canada does not have enough control to
mandate amber turn signals?

You just can't do a good study on this. During the time period
that the CHMSL's were put into effect, other safety improvements (such as
ABS) that would have reduced rear-end collisions also became more prevalent.

Also, automotive styling has changed, it seems today that smaller tail
lights are
more popular, which would of course increased the importance of a CHMSL.

I also see CHMSLs all over the map, some are at eye-level, others at the top
of
the vehicle. Some are big, some are small. Has anyone done a study on what
specific design of a CHMSL is most effective? And why not mandate that
design?
(because it doesen't matter if they are there or not, that's why, so let the
stylists
put them wherever they want)

And, let's look at the theory a second - the theory is that CHMSL's put a
big
red light right in the tailing drivers face so he notices a brake light
faster - only
problem here is that the tailing driver doesen't sit in the CENTER of the
car! He
sits on the left. If the theory of the CHMSL really worked, then you would
see
an even MORE improvement by mounting the extra stop light to the LEFT of
center - except in Britian of course where it would need to go to the right
of
center - but once again, this isn't mandated either. Why, because once
again
you can't prove that there's a benefit - because the theory itself is wrong.

The problem is that this is one of these safety improvements that nobody can
argue
against. Costs to add an extra light to the vehicle are miniscule, there is
no possible
way the extra light can increase collisions, no automaker gets a competitive
advantage
over another because they all have to do it, and it's political suicide to
argue against
it because your perceived to be against "increased safety"

People claimed that the 55Mph speed limit saved thousands of lives a year,
and
as such this perpetuated the speed limit for nearly a generation. When it
was finally
repealed, all the studies claimed that it would kill thousands more people.
What
happened? highway deaths went _down_ after it was repealed. Of course the
studies that claimed deaths would go up were quickly forgotten and swept
under
the rug - instead of being held up as a model of the failure of the safety
study
process.

For the record I am not advocating removal of the CHMSL at this point. In
my
opinion, the money spent on it and on justifying it was a waste, and there'
s no point
in spending further money proving they don't work then spending even further
money getting the world's governments to again rewrite their laws. It's
cheaper
to just leave things as they are. But I am not under the delusion that they
do any
good, other than the good that is done by compensating for too-small
tailight designs
that should never be on the car in the first place.

Ted

 

On what grounds do you disagree? Personal opinion, or some data you
haven't yet shared?

The very same.

The same way the US had perfect control over banning DRLs for five model
years when Canada mandated them. The same way Canada has perfect control
over permitting ECE headlamps while the US bans them. The same way the US
has perfect control over banning fog lamps as DRLs while Canada permits
them...and so on and so forth. If Canada were tomorrow to say "No more
CHMSLs, we ban them", there'd be no outcry from the manufacturers, who
would simply omit the device, the bulb, or leave it disconnected (as they
currently do for international markets that prohibit CHMSLs, though there
are fewer and fewer of those.) However, if Canada were tomorrow to say "We
require amber turn signals", there would be an enormous outcry from the
manufacturers on grounds of trade restriction, since they would have to
tool for and equip their vehicles with a new device.

Outside North America, the situation is even clearer: When the world's
lighting experts convene to discuss new ECE regulations, every country's
expert has the power to kill a proposed mandatory device. All the
signatory countries have to agree to a regulation's language and
provisions before it's put into place. That means the specs,
mandatory/optional status, wiring requirements, and just about every other
aspect of any automotive lighting device usually undergo enormously
protracted discussion and debate, and the mandate for the device can be
held up for years if any signatory country wants to do more research or
sees a reason to prohibit the device.

Perhaps *you* can't, but there exist people who can.

You've never heard of controlling for confounding factors? It's Research
Methods 101 stuff.

Donno where this subjective impression gets its root in your head;
I can think of plenty of vehicles with large-area taillamps...there are
legal minimum projected-area requirements for all exterior lighting
functions.

Yep, and you can find it and its abstract (and the whole study, if you
want to pay for copying and shipping) at the UMTRI library online.

THere are legal requirements for size, position, intensity and angle of
visibility of the CHMSL. Stylists are NOT allowed to put them "wherever
they want".

No, the theories are:

1) The CHMSL is closer to the axis of the following driver's field of
view, and

2) The CHMSL is visible through the windshield and backglass of
interceding cars.

And data didn't bear this out. Data bear out the CHMSL safety benefit.

DS

 

Oh yeah, one more thing:

Germany tried high mount brake lamps mounted at the left and at the right
of the rear of the vehicle, back in the early 1980s. The safety benefit
was not found to be as great as with the single center lamp.

So much for your "theory".

DS

 

Art Begun wrote:

Seemed to have written nothing actually.

False alarm?

 

They imported a bunch of late '70s Toronados? I would have thought they'd be
a bit large for most city driving there...


--Aardwolf.

 

*Heh* You're not wrong - I once saw an '86 Chev Caprice Estate station
wagon make a 46-point left turn from one narrow London street into
another.

The German dual HMSLs were higher than the Toronado ones - about midway up
the backglass.

DS

 

Hard to tell - don't know if he was referring to me or "mic". Perhaps he will
enlighten us.

 

And for yours. As you said:

No, the theories are:

1) The CHMSL is closer to the axis of the following driver's field of
view, and

2) The CHMSL is visible through the windshield and backglass of
interceding cars.

So, when Germany put them right in the axis of the following drivers field
of view, instead of off to the right (where they are when they are in the
center)
then the results were _worse_? So much for that theory.

"controlling for confounding factors" that's a laugh. Every study author
claims to be able to do that. It's only possible when the outcome to be
measured
is grossly large - such as for example a study that shows something
spectacular
like 90% of rear-end collisions were prevented by CHMSL. Not when
the outcome is barely significant.

And as for stylists not being allowed to put them where they want, what
about the CHMSL on the back of the latest Yukons? It's a row of tiny LEDs
that is on the very top of the vehicle - definitely way too high to be
visible
"through the windshield and backglass of interceding cars" and if you drive
to
about the 8:00 position of the Yukon and look up to your right, the rise of
the
back door makes them practically invisible.

And as for the retooling costs goes, if Canada mandated amber there would be
an outcry, if Canada mandated the CHMSL _before_ the US did, then there
would
be an outcry using your logic. Yet you said that every country was free to
adopt
the CHMSL or not as they chose? Bullshit. It sounds like every country was
only free to adopt them when the major automaking countries had decided to
get together and adopt them, thus guarenteeing that just about every car
made
already had the light in it. Only in that kind of situation - where the
light exists
regardless - can a country not adopt them and just have the automakers
disconnect
the wire.

Your description sounds very much like the attitude I said that I have
taken -
once the major countries had been snowballed into doing them by the
do-gooders,
the rest of the world figured they wern't going to waste time on fighting
such an insignificant
issue. As you said "mandate for the device can be
held up for years if any signatory country wants to do more research or
sees a reason to prohibit the device." well why would anyone see a reason to
prohibit a
lighting device that does nothing?

Ted

 

It all depends on what the user wants. A police cruiser in the US may
have absolutely no desire for a beacon (in fact, I haven't seen a beacon
on a police car here in at least the past ten years), but slow-moving
vehicles like forklifts, parking enforcement, security patrols, etc.
require only the basics that a beacon provides. Police have higher
intensity requirements, but both types are warning lamps.

 

The "Plastic Vantastic" Pontiac Trans Sport has the whole shebang
running from roof hight down to wasteline - plus the center lamp.