Buttons Down

The New York Times reveals what Gotham pedestrians have long suspected: Those intersection buttons that promise to activate the crosswalk signal generally don't do anything. The Times reports that "more than 2,500 of the 3,250 walk buttons that still exist function essentially as mechanical placebos." But if enough people push them simultaneously, the color of the national terror alert changes.

Comments

[Jason Ligon]

Man, rough day for joe around here.

In Japan, they have music that tells the blind people when to cross the street. I'm glad the music isn't just randomly turned on to make people feel better ...

[Highway]

joe, Citizen and others are probably right that the downtown NYC buttons don't really need to be there. For a couple reasons, actually. One is that foot and car traffic in NYC is so heavy that crossing signals are just programmed into the cycle anyway, with no differences in timing based on use. The other reason is that people in NYC aren't real shy about crossing the street whenever they want, regardless of the current light.

So to recap, pedestrian signal actuators don't make a lot of sense in Manhattan and highly urbanized areas of NYC, since they're redundant. People will get crossing signals anyway. The actuators ARE needed at the location with 10 vehicles per hour, because otherwise there will be no crossing movement of cars for pedestrians to cross with. The 'all-red' pedestrian movement is VERY rare, and is probably NOT actuated with a pedestrian pedestal, as the foot traffic required to warrant it is so high that it is built into the signal timing anyway.

The locations where you do need the actuators are the ones that infrequent crossing traffic is expected, in order to interrupt the green time, as you stated. Those locations will also usually have a cross-movement built in to them, not tied to the actuator, in case the actuator malfunctions or the driver/pedestrian manages to not trip it.

[Peter]

Next topic: does the "door close" button in my building elevator really work, or is that just what They want me to think?

[Russ D]

If someone knows this, I'd love to know the answer.

You often see the actuators in the pavement 100-150 feet or so from the intersection. Is this to signal that if a car is "on" the actuator" that enough cars are queued up or is it used as an indicator of how many cars are passing over it in a given amount of time? Because if it's a queuing thing, it suggests there are 8-10 cars queued. But there doesn't seem to be a pedestrian equivalent if that's the case (unless pressing the button 8 times does the same thing).

[joe]

Highway,

The Westchester Main Street doesn't need an actuator because the low volume of traffic provides plenty of opportunity for people to cross without needing a red to stop the cars. The old fashioned "look both ways" technique works there, even when there is a green light, or no control at all, at the crossing point, if you assume (as I did) a low enough traffic volume.

Now, in mid-town Manhattan, whenever the cars are allowed to travel, there are going to be cars moving across the crosswalk. New Yawkiz may not be deterred by a DONT WALK light, but a steady stream of cabbies barrelling through the intersection is another matter. The only way pedestrians can get a safe opportunity is to stop the cars somehow, either with a dedicated pedestrian phase, or with a button. Though you're right, if you have the one, you don't need the other.

You are right about the rarity of all-red pedestrian phases. Usually, people get the WALK light at the same time that the cars next to them get the Green that allows them to turn across the crosswalk. Never understood that.

[Russ D]

joe, are you suggesting people should cross while the light is red? Looking both ways may be practical, but who knows what Bloomberg's cops are going to write tickets for next.

[joe]

Russ, I think it's done that way to allow enough lead time for approaching cars, so that the light facing the other direction can go through its yellow phase to red, and the light in your direction turn green, at about the time you actually get to the intersection.

That's my guess.

[Jay]

Is this feed the traffic geeks day at Reason? Well let me clear my throat.
a) as already pointed out, there should be no need for ped or vehicle actuation in a highly urbanized downtown with regular, predictable demand on all the approaches.
b) whether actuated or not, if the signal is coordinated in a network, there is a minimum cycle time that has to be respected to service main street traffic and keep adjacent signals in synch. when the button is pressed, its similar to pressing the button for an elevator, a "call" is placed and depending on where the internal clock is on the intersection cycle (anywhere from 60 to 120 seconds) you will get a walk signal at the next allocated phase window. This is why sometimes it appears as though the signal responds instantly and other times it takes forever depending on when you press the button (sort of like what floor the elevator car happens to be on when you request it). Banging on the button does nothing.
c) the wire loops in the pavement are used for vehicle actuation and sometimes phase extension if located near the stop bar. Sometimes the loop is set about 3 car lengths back to activate a left-turn signal. If its a square loop waaay back of the stop bar, its probably a dilemma-zone protection device, which can extend the green time for an uncoordinated signal (usually off-peak or late at night) and reduce the change of red light running or sudden stop. Some of the loops are also used to gather flow data and adjust on the fly as necessary.
d) whether its a car or pedestrian requesting green does not matter to the controller, you both wait the same amount of time. The only difference is the minimum amount of time that is provided when the phase comes up.

whew....

[joe]

"joe, are you suggesting people should cross while the light is red? Looking both ways may be practical, but who knows what Bloomberg's cops are going to write tickets for next."

Ha! They probably already do, actually. It's called jay-walking.

Which is probably a much worse idea in NYC than in my imaginary Westchester suburb.

[Highway]

Answers!

For Russ (trying to de-jargonify Jay's answer)
In general, you'll see square shaped loops in the pavement in advance of the intersection, and you'll see longer rectangular detectors AT the intersection. The advance ones are 'passage' detectors, that say when a car has passed over them, and are generally for extending green time on an intersection leg. Most signals have a minimum green time on each leg, and a maximum green time. After the signal turns green, it will turn yellow at the minimum time unless it receives a signal from the advance detector of more traffic. Each actuation will increase the green time up to the maximum, at which it will always turn yellow then red. The longer loops indicate vehicles sitting at the light, waiting for it to turn green, or waiting for a left turn signal. That's why you have to prod the little old lady to pull up to the stop bar to actuate the left turn signal, or you'll be sitting there all day.

joe,
As I said earlier, dedicated pedestrian movements are very rare. Even if the actuators worked, they wouldn't cause this type of movement. Nearly all pedestrian crossing runs afoul of right turns. However, the pedestrians in the crosswalk DO have right-of-way, although this relies on the cabbies to yield. In my city walking experience tho, most people are loathe to run over pedestrians, and the right turn movement is supposed to anticipate the possibility of pedestrians. The 'safety' of such a movement is debatable, but putting in exclusive phases for pedestrians will still put them in conflict most places, as right turn on red after stop is generally the law. Such a movement would also be rarely warranted. If you see an intersection that would warrant such, contact your Department of Public Works and they will usually be very responsive in investigating it.

Also, another geeky engineer thing to start looking out for is the disappearance of the roadway loops, as they are being out competed by video detection. Those cameras you see up on top of the signals probably aren't spying on you. 🙂

[Mark Fox]

Highway: Yet...

The tinfoil shroud really takes the joy out of driving my convertible.

Peter: Thanks for bringing up those elevator buttons. To me it seems most of them work, but not instantly. Press the button and the door begins to close in a second or two rather than the few to several seconds if unpressed.

Any elevator engineers care to explain load sensors and audio monitors in our vertical transportation infrastructure?

[Jay]

The "ped scramble" signal phases Joe and Highway have mentioned are quite common in Montreal where right turns on red are still prohibited (of course this point is somewhat moot in that most Quebec drivers still tend to go through and left on a red if necessary). The controllers usually display a green "through" arrow and a red ball simultaneously to give peds a head start into the intersection before conflicting turning traffic is permitted to move on the "green ball".

[Native NYer]

Ticketing jaywalkers was what drove Guiliani's ratings down in NYC.

Sodomy by police and shooting Amadou pissed off the activists, but when you start ticketing folks just trying to get to work quicker your days as a NYC politician are over.

I'm betting if Bloomberg is voted out of office, the reason won't be taking control of the schools or tightening the budget on social services, but making average folks in bars go outside to smoke.

[Mo]

I got a jaywalking ticket out on Sunset a few months ago and was more upset than all my driving offenses combined. The fact that it was 90$ and less than running a stop sign, only outraged me more. That the light was green and I hadn't hit the button made it worse. Add on top of that the area had a bunch of drunk drivers around, since the bars were closing, who were bigger fish to fry than myself and my friends. Well, I was outrage. Jaywalking ... feh.

[joe]

I've been told that people who jaywalk in Japan are berated by outraged passersby.

[dj of raleigh]

> Heh heh.
I have freight trains going by all night.
At least the RR crossings work.

[jones]

Would you please sell me some of what you're on, dj? It seems really sublime.

[garym]

Speaking of revealing things one has long suspected, I finally blew up the display in my browser enough to realize that my eyes aren't going bad; the message text in these forums really is in gray! Obviously it's part of the webmaster-optometrist conspiracy...

[joe]

That's really discouraging. There are very few places where those things actually make sense, but highrise areas of New York actually are one of them.

You just know that the pedestrian button between the tennis courts and the cafe on some Westchester Main Street with 10 cars/hour works perfectly. sigh.

[Needler]

Poor Joe. How do you sleep at night?

[joe]

I'm usually murmurring "asphalt...concrete...pavers...asphalt...concrete...pavers..."

[Needler]

Heh heh.
I have freight trains going by all night.
At least the RR crossings work.

[J.C.]

Another case where the true believers of these systems didn't take nuance into account. But they sure cost a lot of money to install.

[joe]

Aw, I hurt someone's feelings.

[Fred]

Hey! A topic I know something about.

Every now and then a city will be given several million dollars to install new traffic control devices to move traffic along more efficiently. The the primary purpose of this is fuel reduction and a consequent reduction in air polution. That is potential specious argument #1.

These traffic control devices consist of inductance loops in the asphalt, new traffic signals and control boxes, a highly sophisticated, computerized control station and cameras installed next to the traffic light.

Potential specious argument #2 is that the computer program and the operator in the control center are efficiently moving traffic along.

Now, I appreciate a good government-funded jobs program as much as the next guy. Heck, as a civil engineer I had the privilege of working on one of those projects.

But here's the tin foil hat zinger: it's all about those cameras. OK, so I lurched off topic, but I had to warn you before it was too late.

I opened up a lot of topics and provided no resolution or even an opinion as to the right and wrong of it all. These are things inspectors and engineers (not to mention construction workers) bitch about. But hey it's about the jobs, man.

Oh yeah, about those push buttons. People figured out long ago that many don't work. I figured it out in 1966, back in the Johnson Adninistration Urban Renewal days.

[Walter Wallis]

When they tore down a building at an army base near here, an engineer salvaged all the thermostats, then fastened one to the wall in every office where he had been receiving complaints of too hot or too cold. Complaints went way down.

[thoreau]

On a particularly trying weekend in the life of my family, I found myself at a street corner with my mother. She pushed the button and waited. Then another woman, one whose clothes were apparently more expensive, also pushed the button. After the other woman was out of earshot my mother ranted and raved to all of us "Just because she has more money than me she thinks I'm too stupid to push a button correctly?!" It did no good to explain that the buttons are a placebo. Then she accused me of thinking that she's crazy.

Normally my mother isn't like that, but it was a particularly hellish weekend for the whole family. And the well-dressed woman didn't help. What, just because she has more money she thinks she has the right to send my mother over the edge and ruin my weekend?!?!?! 🙂

[Critic]

Man, this thread is going nowhere fast. If only I had a button to move it forward...

[Citizen]

I'd think that downtown NT wouldn't need functioning crosswalk buttons. Obviously pedestrians are there, it's gonna give a walk signal no matter what. In a seldomly crossed intersection is the only place that you'd actually need one - because there won't be users during every traffic cycle.

[J.C.]

"Man, this thread is going nowhere fast."

That'll happen when joe's trolling.

[joe]

Citizen, pedestrian crossing lights can be set to always include a pedestrian cross/red lights all around period as a phase of each cycle, or they can be set to cycle through greens in each direction until someone presses the button. Sort of like when a side street meets a major street, and the main street always has green unless a car approaching on the side street sets off a detector.

[Russ]

Despite the fact that I seldom agree with him, I think that it's pretty unfair to accuse joe of trolling.

[Citizen]

Maybe I'm missing something. Why then would you need functioning buttons downtown NY? Isn't it a given that pedestrians would be there? The Westchester Main Street seems like the place you would *want* functioning crossing buttons. Are people in disagreement?

[obvious]

Joe is not a troll.

He is a dickus.:-)

[Douglas Fletcher]

I happen to know that the button for crossing Rockville Pike westbound at Twinbrook Parkway actually makes an elevator at the Naval Hospital shake for 1/4 of a second.

Please don't ask me how I know this.

[Douglas Fletcher]

I also happen to know that 'dj' isn't on anything.

His posts are actually very loosely structured to mirror the development of poetic imagery in the songs Bill Monroe recorded through the 1950s. It's a very large and difficult project, to say the least. Also, like Ezra Pound's 'Cantos,' it is difficult at times to understand unless you know which song he is referring to from post to post.

Seriously, just ask him.

[Douglas Fletcher]

Speaking of jay-walking, the other day I thought I'd use the local cross-walk near where I live instead of jay-walking like I usually do (it can be dangerous). Wouldn't you know it, some ditz makes a left turn without looking and almost leaves me splattered in the crosswalk.

It's harder for them to hit you if you don't walk in a straight line.

[Walter Wallis]

Geeezzz! You are on to the pedestrian buttons, and the elevator buttons. Next thing someone will spill the beans about the voting machine buttons that are not connected to anything and then us electrical engineers will never have any fun any more.

[curious]

Is this similar to splashing a bit of water on your hands after going to the bathroom?

[Rico Rizzo]

I'm walkin' here! I'm walkin' here!

Rizzo

[Thacher Robertson]

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DATE: 05/21/2004 06:08:44
Just because there's a pattern doesn't mean there's a purpose.