

Brake lights sensitive to braking force - pedrokost
http://blog.pedro.si/brake-lights-sensible-to-braking-force

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duck
I've seen some semi-trucks that have something like this (except it was
simpler in that it was a straight light that would grow from the inside out),
but do you really need them? If you just leave enough space in between you and
the person in front you will never have a problem. Plus, it already is a pain
to change out bulbs in some of these newer cars... I would hate for it to get
harder (and more expensive).

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pedrokost
Many crashes are caused by the lack of such lights. And if such a system can
be implemented at low cost (which it is), then why not use it? A saved life is
worth more that the implementation cost.

Maybe it can be at least partially be achieved with LED lights that last many
years and don't break easily, if at all. Anyways I have the impression that
the quality of light bulbs has increased a lot since the burst of the auto
industry.

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tejaswiy
It exists already -

[http://www.usautoparts.net/bmw/technology/brake_force_displa...](http://www.usautoparts.net/bmw/technology/brake_force_display.htm)

<http://www.google.com/search?q=break+force+display+bmw>

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pchristensen
Had this discussion with a friend 13 years ago in college. Didn't know how get
it to market and IIRC my friend found someone else had a patent on it.

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micheljansen
I completely agree. In 2008, some students actually made this already:
<http://www.physorg.com/news125773212.html>

I wrote about it back then (in Dutch,
<http://micheljansen.org/blog/entry/471>) and at that time, there were some
laws preventing this from really catching on. I guess those have been changed
in the mean time?

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afshin
This is a really useful idea and gives useful more fine-grained information
without compromising the overall message: "I'm slowing down."

Along a similar vein, I want car horns to be as loud inside a car as they are
outside, to ensure they're _only_ used for emergencies. I live in a city and
car horns dramatically reduce quality of life because "no honking, $350
penalty" are never actually enforced by the police.

~~~
hallmark
Re: honking. Don't travel to SE Asia; you'll be horrified.

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robinhouston
Funny, a very similar idea was discussed here a couple of months ago, when
jgrahamc mentioned it was idea 999 in one of his ideas notebooks:
<http://blog.jgc.org/2010/10/1000-bad-ideas.html>

Here's the discussion: <http://news.ycombinator.com/item?id=1779339>

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mbyrne
I suspect this is one of those cool ideas that in practice doesn't work so
well, unfortunately.

But increasing brake light intensity overall on new cars or replacement brake
lamps would increase safety even though old cars might have weaker brake
lights. Essentially an "Omigod!" mode.

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pilom
Best one I ever saw was at Carnegie Mellon. They integrated this onto a CAN
bus and were in talks with Bosch.

<http://www.ece.cmu.edu/~ece549/spring10/team7/index.html>

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osf10
I remember reading about a similar concept by Citroen I think about 15 years
ago. The brake lights would be a much pinker shade if the brakes were applied
sharply.

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nodata
Strong braking normally == hazard lights + brake lights on new cars.

It's quicker to recognise than a graded red brake light.

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sambeau
If you are close enough behind to really tell the difference you are probably
already too close.

~~~
pedrokost
That's what the blue 'max deceleration' border is necessary. At least it makes
it easier to see it from further away.

Maximum deceleration values of a car are about up to 1G for normal cars (found
the data on an unofficial forum, so it may not be right)

Suppose a car in front of you brakes slowly, but for some reason you press
harder the pedal, say to a deceleration of -5ms^-2 (1/2 G). Suppose a town
with speed limit of 50km/h, and you and all cars drive at max speed. Suppose
an initial car separation of 20m. If you do the calculations, you'll see that
it will take less than 3 seconds for the back car to crash your car end. 3
secs sounds like a lot in reaction time, but the driver may be distracted,
which may make him notice your braking a bit later, but not too late to apply
appropriate braking and causing a car on his end.

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nodata
s/sensible/sensitive/;

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pedrokost
Thanks for the notice. I fixed it.

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goldenthunder
The new Ford Mustangs have a kit you can install that does just that. I
thought about this a few years back and want it so bad!

