
Safety Feature For Pedestrians Has Undesired Consequence - eroo
http://www.npr.org/2014/07/01/327199161/safety-feature-for-pedestrians-has-undesired-consequence
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incision
I sit above a pretty busy intersection and get to witness the madness and
regular accidents of rush hour traffic heading out of downtown on a daily
basis.

I think simply shimming an extra second or of intersection clearing time
between transitions would go long way towards addressing the apparent dangers
of light timing.

Activating traffic signals and pedestrian signals simultaneously results in
drivers who try to 'beat' the pedestrians off the curb.

Activating perpendicular traffic signals too close traffic/pedestrian signals
puts the cross-traffic in danger of being hit by the people trying to time the
light.

Add a second or two, end up with <5 fewer light transitions per hour.

Though, on a related note, what I see cause more accidents and general
bullshit than timing lights is the ridiculous amount of cellphone use that
happens in motion and particularly at intersections.

Every day I see someone stop at the red light below me and immediately start
fiddling with their phone, as the light turns green and the fiddler proceeds
to hit the gas _irrespective_ of what is happening in the road directly in
front of them - pedestrians, gridlock, presidential motorcade only to run into
something or panic stop seconds later if they're lucky.

At first this seemed inexplicable..."Can't these people see?"

Upon thinking about it, I'm guessing they actually can't or more accurately
don't see. That the fraction of a second they have to hit the gas before
getting a chorus of horns or a rear-ending is simply too short to take in even
major changes in the scene in front of them.

Self-driving cars can't come soon enough.

~~~
fredophile
I've never seen an intersection that didn't have some amount of time where it
was red in all directions during a light change. I can't find references to
back it up right now but I'm pretty sure that in cases where this period is
extended you end up with drivers adapting and driving through a stale yellow
that they would have previously stopped for.

~~~
jgh
In most of California it seems that the next set of lights turns green as soon
as the previous set turns red. In Ontario, Canada I believe there is a 2 or 3
second delay. I don't think that I've noticed any difference in the behavior
of people around yellow lights except for the fact that in California it seems
people are more willing to run red lights, and the intersection is almost
never clear when the next green light happens (unless, of course, traffic is
sparse). In Ontario, Canada the intersection is almost always clear when the
next green light happens.

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Retric
In the trade off between property dammage and pedestrian deaths I am generally
going to side with pedestrians.

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mianosm
It is an interesting scenario that they play out in Toronto. However, this is
a programmatic feature built into the traffic systems - and in the current
location I live in completely different.

Here the countdown hits zero well before the lights shift to yellow and
finally red. Perhaps Toronto needs to readjust if there is a high number of
rear-ends occurring due to drivers going off of the pedestrian control devices
instead of vehicle control devices.

~~~
clarkmoody
My experience is that the light changes to yellow as the countdown reaches
zero.

~~~
Fuzzwah
Here in Phoenix most work this way, but when a road crosses central avenue the
walk counter hits 0 and then there is about a 10 second delay before the
traffic lights change.

The problem is, people have realized this. So peds continue to begin crossing
as the counter gets low (central has a lot of ped crossing because the light
rail runs down the middle of the road).

~~~
couchand
They really ought to reverse that. Make the light shorter for cars and drivers
can no longer use the countdown clocks as a signal. They'd have to actually
look at their own light. Combine that with starting the pedestrians early and
you make it much harder for drivers to be jerks.

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ripter
It reduces the number of pedestrians who get hit, and asshole drivers who
think they can speed though intersections are getting into accidents.

I don't see the issue.

~~~
diminoten
Who do you think the asshole drivers run into? According to the article,
drivers who are just trying to be safe by not risking it and slowing down get
hit by drivers behind them who speed up.

~~~
jessaustin
_...drivers who are just trying to be safe..._

If their idea of safety is paying attention to pedestrian signals rather than
automotive signals, we'd rather they not bother.

~~~
diminoten
Who said anything about "rather than"? What kind of a signal do you expect
someone about to rear-end you to give?

~~~
jessaustin
They should be looking at the signal that consists of a red lamp above a
yellow lamp above a green lamp. While the green lamp is lit, they should keep
driving and not slam on the brakes just because the little man in the
crosswalk started blinking.

Yes I know that rear-enders are _at fault_ even when the rear-ended did
something stupid. In fact many driving accidents can be attributed to the
stupidity of multiple parties, and the accidents described above can also be
so attributed.

~~~
jgh
The driver behind them should be watching the car in front of them and be
following at a safe distance. I don't see why you should run into the back of
someone if they slow down for an intersection with 1-2 seconds left on the
timer and they're at a questionable distance about whether they'll make the
light.

~~~
jessaustin
It's as if you didn't even read the second paragraph, in which I _also_ blamed
rear-enders for rear-ending!

If the light is green, there's nothing "questionable". Either one will make
the light, or one will have time to slow once it actually turns yellow. If,
instead, one does something surprising and irrational, misfortune may result.
In this scenario, as in many accident scenarios, _both_ parties have driven
poorly.

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brownbat
Even if we don't get fully self-driven cars soon, I really hope we get
autopilot to take over for timing left turns and yellow lights, entering a
highway, avoiding pedestrians, and maybe all parking.

Sure, many drivers handle that all fine most of the time, but each one seems
like a potential point of failure that would benefit from a little more
standardization.

EDIT: Or traffic robots that direct instructions to proceed or stop to each
specific driver. Seems like we have better options than a colored indicator
involving a lot of judgment calls based on conflicting interests.

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datr
I'm having trouble understanding this article. If the count down timers show
pedestrians the amount of time they have to cross the road (as they do here in
London) why would the driver be watching this and think they only have a few
seconds until the light goes red and they can't get through the intersection.
Surely, the opposite is the case?

I can see that you could potentially form a similar explanation around that
scenario too but it doesn't seem as convincing.

~~~
threedaymonk
Pedestrian crossings in the UK are rather unusual compared to most other
countries in the world, in my experience.

In most places, crossings work on a parallel/perpendicular system: parallel
roads and pedestrian crossings are red or green[1] at the same time. This
means that cars turning across a pedestrian crossing must give way (yield) to
pedestrians.

The UK system, by contrast, isolates the pedestrian phase from traffic phases:
when the green man (the WALK indicator) is displayed, no vehicles will
approach the pedestrian crossing from any direction. The time between
pedestrian crossing opportunities is longer, but there is no contention for
the crossing from cars turning into the road.

The article describes the parallel/perpendicular system. In this scenario, a
driver will see a parallel WALK light and a (vehicular) green light at the
same time. As the pedestrian crossing typically goes red earlier (because
people take longer to cross the road than cars take to cross the
intersection), a car driver who watches the pedestrian crossing light or
countdown timer gains advanced knowledge of the parallel traffic signal.

1\. Or white in some places in the US!

~~~
Rapzid
New Zealand has a mix. All stop, all direction crossings are usually reserved
for downtown high pedestrian flow intersections.

There is also a distinction between green and green arrow turns. Green arrow
indicates safe turns and green means yield to traffic/pedestrians.

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foobit
I like how traffic is kind of organized in Paris: Pedestrians will cross the
street whenever they feel like and don't care much about the signals. Because
of that car drivers will constantly watch out for jaywalking people, drive
with responsible speed and rather stop too often than being cited for reckless
driving. All in all this works out extremely well and I always feel like this
the safest city for a pedestrian.

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miketesch
It's possible that the lowered rate of accidents involving pedestrians can at
least partially be attributed to the fact that drivers can see the timers.

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barrystaes
Good grief.. the article ends with "Install them so that the pedestrians are
aware of the timers but the drivers are not. And one way to do that would be
to broadcast the timers via audio so that the pedestrians can hear the
countdown clock go down, but drivers cannot."

The defacto standard in the Netherlands is that a pedestrian stop makes a loud
ticking sound to aid blind people.

When its about to jump to red (lets call this orange) the pace increases,
before going calm (not loud, and low pace) when the light is red. The orange
period is -say- the time it takes an elderly lady to cross the street.

Here, we dont need countdown displays. People should be able look at the
oncoming traffic instead.

~~~
walshemj
quite a lot of lights in London (uk) have a count down for the pedestrian side
- its just the nutters on fixed wheel bikes who blast through junctions at
25-30mph you have to watch for.

If you think I am kidding about the fix wheeled bikers visit the junction next
to Holborn tube.

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jcampbell1
I'd like to see a study of red light countdown timers. I have only seen them
in China, but I think they are awesome. The timer tells you how long until the
light turns green. If it is 30 seconds, you can check your text messages, or
adjust the radio, but when it hits 3...2...1... everyone goes at the same
time. I have never seen so many cars make it through an intersection in a
single light cycle.

I have a feeling it is good for safety as well because drivers get some
downtime, and a timer that lets them know when they need to be back at full
attention.

~~~
tacticus
And then you have the dicks who will move at -1 second and jump the lights
without checking that it is clear.

~~~
PeterisP
Well, this can be solved by well-known practices of red light cameras and
revoking licences for repeated violations.

I mean, what you describe isn't a problem with timers, it's a problem with
some dicks that are dangerous to others (not only in this situation but
others) and should be prevented from driving at all.

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jrockway
Even when the intersection doesn't have the countdown timer, I memorize the
number of "hand flashes" before the light changes and use that to figure out
if I need to speed up to get through. This is on a bike, though, so hardly
life threatening. The timers are actually very convenient, especially in New
York with long yellows and long 4-way reds. 1 second? More than long enough.

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taylorjbrennan
In this context, it's a "cheat" for drivers with greater awareness, and one
can't assume the driver in front knows to accelerate. Perhaps it would be
safer if the timers were installed on the drivers' traffic lights as well.
I've seen them in China and I liked the idea. What's stopping automobile
traffic timers from being installed in the U.S.?

~~~
Fuzzwah
We have pedestrian walk timers here in Phoenix and they are very easy for
drivers to see.

The situation described in the article happens when a driver is approaching a
traffic light which is green but notices that there is only 1 or 2 seconds
left on the walk count down and decides to stop. A driver behind, who may or
may not have seen the count down isn't ready for a car to begin stopping as it
approaches a light which is still green. Bang.

~~~
adnrw
I think you've slightly misrepresented the second driver's intentions. The
article says:

"...the guy behind, he sees the two or three seconds and thinks, oh, the guy
in front of me is going to floor it too, I'll floor it and we'll both get
through the intersection. Whereas the guy in front thinks, OK, I only have two
or three seconds left, I'm going to slowdown."

So it's not that the driver in front sees the timer and stops during a green
light, whilst the driver behind doesn't see the timer and isn't expecting to
stop during a green.

More likely that both drivers see the timer and make conflicting decisions:
the driver in front decides there isn't enough time and slows down; the driver
behind decides there is enough time and speeds up, having assumed the driver
in front would be doing the same.

However, your scenario is plausible too and just as problematic.

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bjchrist
Can't wait till we get self-driving cars. Next generation will find it
completely reckless that we put people in charge of driving cars

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ryusage
Weird. I wonder if this is primarily a problem in larger, more congested
cities where people tend to drive more aggressively. I live in a smaller city
where we've had these a very long time, and they don't seem to inspire the
kind of behavior they're talking about here. But driving here is also
significantly less aggressive than somewhere like, say, Chicago.

~~~
aidos
I wonder if there's any weight to that assertion of a correlation between city
size and aggression.

I live in London and I generally find that the behaviour is surprisingly
courteous. My suspicion is that it's because many (most?) roads are actually
too narrow to have two cars pass at the same time so people are very used to
having to pull over to get out of each other's way.

Obviously, all totally anecdotal, but there must be some research on it.

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WalterBright
With all this focus on self-driving cars, nobody is looking at the low-hanging
fruit - cameras on the traffic lights. No, not for ticketing people, but for
changing the signals in a way that maximizes flow. This will save time and an
awful lot of gas. With all the sophisticated camera algorithms these days,
this should be a relatively simpler problem to detect the speed, number, and
distance of cars coming from each direction.

It can also be used to save lives - the light for the cross street need not
turn green when the other turns red if there looks like a car is going to run
the red. If there are pedestrians in the intersection, the lights can also
remain red.

~~~
robryk
You can detect speed,ount and types ofcas with a pair of inductive loops (car
length determines the type pretty well). I'd guess that putting such a pair
some distance before the intersection would be a lot simpler (cars would
obscure each other in the camera's view). That said, this would give you
information about cars passing a single point on the road and would give you
no information about pedestrians.

~~~
mpasternacki
This has been implemented for some traffic lights in Warsaw, and has one more
bad side effect (possibly because of bad implementation): if you a bike in the
late evening on the smaller street, that's configured "red unless there's a
car that will be crossing" to maximize throughput of the bigger street, you
have to wait for a car or use a pedestrian crossing, because the loops won't
detect a bike.

~~~
mnw21cam
Lots (most?) of the traffic light controlled junctions in the UK have
induction loops to detect cars. I have personally complained to the
authorities about their lack of ability to detect bicycles.

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GotAnyMegadeth
There are/were a couple of junctions in Phnom Penh where the traffic lights
for the roads have count down timers on both the green and the red. All the
motorbikes started going around the 5 second mark meaning there was a good few
seconds of everyone going from both directions. I'm sure it's pretty
dangerous, but it was fun to navigate

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__david__
Seems to me they could put blinders on the crosswalk timers so they are only
visible from the corner and not from the middle of the street. They already
often do similar things to left turn lane arrows (so that when you aren't
turning left you don't see green out of the corner of your eye and jump the
gun).

~~~
lotharbot
As a driver, I really like these timers. I can see from a block away that I've
got 15 seconds (and will make it comfortably) or 2 seconds (and may as well
slow down now since I won't be anywhere close).

As long as the blinders weren't too restrictive, my use case would still be
viable.

~~~
angersock
That's _exactly_ the use case that they caution about--drivers at different
distances interpreting the signals differently, causing accidents.

~~~
lotharbot
The use case they caution about is drivers reacting suddenly to short clocks
-- flooring it or slamming on the brakes -- when they're very close to each
other. They're talking about how people react to a "2" when they're 2.1
seconds away from the intersection and right on somebody else's tail.

I'm talking about reacting from a long distance out by subtly adjusting speed
(obviously in conjunction with reading traffic -- you don't accelerate if
there's a vehicle right in front of you.) If you're 10 seconds out and see a
2, there's no differential reaction, likewise if you're 10 seconds out and see
a 20. Even if you're 10 seconds out and see a 9, the difference between
"slight acceleration" and "slight touch on the brakes" isn't significant
unless you're already driving too close for the circumstances I drive under.

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nisse72
Here in Auckland, I think we only have those countdown timers at intersections
where pedestrians can cross in all directions at the same time, so there are
no cars speeding up to make the light, all of the cars are stopped.

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learc83
Seems like they could easily fix this by installing some kind of small plastic
guard to keep most cars from seeing the countdown.

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stuaxo
In London we have the opposite, timers for how long you are allowed to cross,
this probably makes more sense.

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logicchains
Why can't they just install more speed-bumps? Scientifically calibrated so
that they only cause damage to cars going beyond an acceptable speed for the
particular intersection in question. I used to live somewhere hoons would
regularly speed by; a speed-bump was built, and it put an end to such speeding
almost instantaneously as all the hoons had their vehicles' suspension
destroyed.

~~~
Anechoic
_Why can 't they just install more speed-bumps?_

Off the top of my head:

\- Given the variety of suspension systems in cars (and available aftermarket
options), trying to make a speed bump targeting one speed (or even a
relatively narrow range of speeds) would be pretty difficult unless you want
to limit all traffic to 10-15 mph

\- Speedbumps on major thoroughfares can cause problems for emergency vehicles

\- (from personal experience) riding over a speed bump (certainly ones that
haven't been well-maintained) on a bicycle is not fun

\- they make snowplowing more difficult (but not impossible)

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seizethecheese
Why don't they just retrofit these signals so that pedestrians can see but
drivers can't?

