Traffic signal

[agentsteel53]

as for flashing yellow ball, I've always seen it paired with flashing red ball, and generally at night.  I've interpreted it as "yellow has right of way over red ... unless red is apparently drunk, doing 60mph in downtown Casper, WY at 4am, and paying no attention whatsoever to signals, in which case just let him burn out on his own time, not yours".

[Mr_Northside]

An arrow signal is designed to control certain movements heading in the direction of the arrow, but doesn't assign right of way any more than a signal with circular indications. (I will concede the point that a green arrow does provide a protected movement, but that is separate from right of way).

As the case with a red arrow. You aren't permitted to turn left with a left red arrow indication.

Except that really has nothing to do with the arrow aspect and everything to do with the RED aspect.  Yielding is not an issues when you can't "go".

I guess if they wanted to replace the doghouse, I wouldn't raise a stink (on a roads message board) if they just had a F-Y-[ball (or "circular")], instead of an arrow.

That's been done, actually. It's called Dallas phasing. I think this photo (by fellow forumgoer US 71) demonstrates the problem with this setup pretty well:

That wasn't what I was referring to.  I was just saying to switch the arrow in a FYA to a "ball".  This appears to just be a standard vertical doghouse with some really wacky timing/phasing.  I don't know that I've seen a situation like that, ever.  And it seems that swapping a FYA for that V-doghouse and keeping the timing, it would still seem wacky.

Yes, most people, if they take the time to think it through, will arrive at the correct conclusion--that a green ball indicates a permissive left turn. But in reality, people don't drive that way--they see the lights, and make an automatic, split-second decision about what the "right" thing to do is. With this setup, too many people saw that the other two lanes were being held by red, and automatically assumed the green over exclusively the left lane meant it was a protected turn.

I guess that's what grinds my gears about it.  It seems like it should be simple enough to inherently know that you always yield to oncoming traffic, unless an arrow "protects" you from oncoming traffic.  Which is why I personally hate the notion of using an arrow for a yield situation.

I would also assume that states that have been using these have adapted their drivers ed manuals to account for this....

And don't get me wrong, as long as traffic moves efficiently and safely, that's what really counts in the end....  Like I said, for some reason these things just bug me.  (Though beyond a couple of minutes typing, I don't actually dwell on it that much)

[roadfro]

I guess if they wanted to replace the doghouse, I wouldn't raise a stink (on a roads message board) if they just had a F-Y-[ball (or "circular")], instead of an arrow.

That's been done, actually. It's called Dallas phasing. I think this photo (by fellow forumgoer US 71) demonstrates the problem with this setup pretty well:



Yes, most people, if they take the time to think it through, will arrive at the correct conclusion--that a green ball indicates a permissive left turn. But in reality, people don't drive that way--they see the lights, and make an automatic, split-second decision about what the "right" thing to do is. With this setup, too many people saw that the other two lanes were being held by red, and automatically assumed the green over exclusively the left lane meant it was a protected turn.

Ironically, if this setup were more common, this would probably be much less of an issue, because people would have become accustomed to the correct meanings.

Yes, this photo shows an application of Dallas Phasing. The error with this installation is that the circular green on the left turn signal is not shielded or louvered in any way from the adjacent thru lanes (nor does it use a programmed visibility head). This leads to an even more ambiguous situation, in that there are conflicting indications on adjacent signal heads. The setup also uses the standard sign, instead of the modified sign "Left turn signal / yield on green [circular green symbol]", which was highly recommended where this type of phasing was in use.

I'm assuming, in that photo, oncoming traffic has green to go straight and a protected left?

I've seen that scenario only a handful of times in my life - and each time, it had the small informative sign.

would a flashing yellow arrow be appropriate in this context?  I've only seen flashing yellow paired with green for the forward directions, never with red. 

Jake, you've got the interpretation correct. Oncoming traffic has a straight ahead and a protected left.

This situation was quite common in some areas of Texas (Dallas, obviously). It was becoming increasingly common in the Las Vegas area over the last several years with at least 20 installations that I am aware of. The whole purpose behind Dallas Phasing was to enable lead-lag protected left turns (thus enabling better signal timing progression) while retaining protected/permitted display for off-peak hours.

This application would not be allowed under current MUTCD rules--it would be replaced by a flashing yellow arrow, and is an ideal situation for an FYA to be used. At the instant the photo was taken, the left turn signal would have a flashing yellow arrow displayed instead of the circular green. In the typical left turn FYA setup, the flashing yellow arrow is tied to the opposing through movement--thus, it can appear when the adjacent through movement is red still allowing the left turn traffic to yield to oncoming traffic to make the turn.

[Central Avenue]

The error with this installation is that the circular green on the left turn signal is not shielded or louvered in any way from the adjacent thru lanes

...How can you tell? It looks like the camera is looking at the left turn signal straight-on...

[codyg1985]

The error with this installation is that the circular green on the left turn signal is not shielded or louvered in any way from the adjacent thru lanes

...How can you tell? It looks like the camera is looking at the left turn signal straight-on...

It is hard to see in the photo, but the left turn signal assembly appears to be louvered. A larger version of the photo shows more detail.

[US71]

The error with this installation is that the circular green on the left turn signal is not shielded or louvered in any way from the adjacent thru lanes

...How can you tell? It looks like the camera is looking at the left turn signal straight-on...

It is hard to see in the photo, but the left turn signal assembly appears to be louvered. A larger version of the photo shows more detail.

It has vertical louvers (I had to pull up my original). Most signals now have horizontal louvers, I believe. I'll have to make another trip up there to verify.

As far as FYA, Fayetteville, AR has thus far refused to install them. I asked Gridlock Guru about this, but I don't remember the city's reasoning (and GG's column has been discontinued)

[PurdueBill]

I forgot that I had taken video in May of a flashing green in action on Eastern Ave in Malden, Mass. 

Here is the flashing green on Eastern Ave, and here is the bottom flashing red on the side street.

Note that Street View shows a pole-mounted signal for the side street that is gone now.  Also, these are somewhat modern signals but still flashing green--most flashing green ones in Mass are older than these, or at least their controllers are old.  Also there are separate Walk signals, unlike many flashing green locations where red-and-yellow indications stand in for Walk signals.

[roadfro]

The error with this installation is that the circular green on the left turn signal is not shielded or louvered in any way from the adjacent thru lanes

...How can you tell? It looks like the camera is looking at the left turn signal straight-on...

It is hard to see in the photo, but the left turn signal assembly appears to be louvered. A larger version of the photo shows more detail.

It definitely didn't look louvered before, but I see it now on the larger version. I stand corrected. But the point about conflicting signal indications still remains.

[PHLBOS]

That's been done, actually. It's called Dallas phasing. I think this photo (by fellow forumgoer US 71) demonstrates the problem with this setup pretty well:



Yes, most people, if they take the time to think it through, will arrive at the correct conclusion--that a green ball indicates a permissive left turn. But in reality, people don't drive that way--they see the lights, and make an automatic, split-second decision about what the "right" thing to do is. With this setup, too many people saw that the other two lanes were being held by red, and automatically assumed the green over exclusively the left lane meant it was a protected turn.

Ironically, if this setup were more common, this would probably be much less of an issue, because people would have become accustomed to the correct meanings.

That long signal-head setup was tried along MA 114 in Peabody, Massachusetts back in 1973 at the Andover St./Pulaski St./Central St./Endicott St. intersection.  Two long signal-heads, mounted on a mast-arm, faced eastbound 114/Andover St. traffic and originally sported only upright and right-turn green arrows below the circular green (which was centered).

The center-green would only light up when left-turns onto Pulaski St./114 East became available in the signal cycle; there was a supplemental ground-mount signal that would had a left-green arrow on the median island.

When left turns were not allowed (so that westbound Central St. traffic can move), the long signal-heads would only display the straight and right green arrows.  The supplemental signal-head, simply displayed a red light (red arrows were decades away).  Note: this phase too place prior to the left-turn movement onto Pulaski phase.

Apparently, after 8 to 10 years, either Peabody or the MassDPW changed the bottom lens of the left-most long signal-head to a left-green arrow and reprogramed the signal so that the center-located green light would no longer light up.  The "NO LEFT TURN" phase now just featured just 3 lenses (2 straight, 1 right-turn) lit on the mast-arm heads instead of 4 (originally 2 straight, 2 right-turn).  The LEFT TURN ALLOWED phase featured 4 lenses (2 straight, 1 left-turn, 1 right-turn) lit on the mast-arm heads.

These 1973-era signals were replaced just a few years ago with a more conventional & modern arrangement; plus, to the delight of many motorists, had the Left-Turn phase onto Pulaski St./114 Eastbound take place on the first green as opposed to later.  The old phase caused many traffic back-ups along Andover St./114 Eastbound for decades.

Note: the nearby signals along MA 114 at the Pulaski St./Gardner St./Pound Ln./Buxton Ln. intersection are also of the same 1973 vintage as the previous signals of the other intersection; they're still presently there but never sported a vertically-stacked 5-lens signal-heads.

[roadman65]

I just saw something unusual in Kissimmee, FL.   Lately the State of Florida has been installing more mast arm signal assemblies than the traditional span wire using the concrete strain poles that other states using those have either metal or wooden type of poles.   However, currently in Kissimmee, FL at the intersection of Vineland Road and Poinciana Boulevard where there has been a mast arm signal assembly for years is now being replaced with the traditional Florida span wires among concrete strain poles.

I think that is odd considering elsewhere the wires are being replaced with mast arms and many new signals are mast arms from instalation. 

[doorknob60]

I'm assuming, in that photo, oncoming traffic has green to go straight and a protected left?

I've seen that scenario only a handful of times in my life - and each time, it had the small informative sign.

would a flashing yellow arrow be appropriate in this context?  I've only seen flashing yellow paired with green for the forward directions, never with red.

If I saw that photo in real life, I'll admit I'd be confused at first, but probably figure it out in time. A flashing yellow arrow would work better there in my opinion, and I've seen plenty of times a flashing left turn arrow with red forward movements here in Bend, so it works fine that way.

[Hot Rod Hootenanny]

Friend of mine posted this on FB yesterday...


Any idea where this is at?

[1995hoo]

Could that be Prypiat, perhaps?

Edited to say: No. Turns out the lights there used a black housing.

[Ian]

Friend of mine posted this on FB yesterday...
<img snip>
Any idea where this is at?

I saw this on Reddit a few months ago. It's at an abandoned children's safety village in Ottawa. Here's a street view that shows it:
http://goo.gl/maps/3orfb

[codyg1985]

^ I was going to guess somewhere in Canada based on the traffic signal head design.

[Takumi]

The elusive double yellow ball. US 301 in Petersburg, VA:

[signalman]

^I assume the green section is a green ball and green arrow on the left?

[Takumi]

^ The green arrow is on the right, but yes, it's correct. The yellow ball on the right is actually pretty recent; it was an arrow earlier this year.

[signalman]

Ugh!  I meant right arrow.     Of course it's a right turn signal, it's on the right side of the mast arm.  However, it is interesting that it was changed from a yellow arrow to a yellow ball.  I wonder what prompted the change. 

[Alps]

Seems wrong for both yellows to be on at the same time. If both the green arrow and the green ball are being terminated the normal display would be just a single yellow ball.

Not unless it was a 4-head doghouse with only one yellow. Yes, it should be a yellow arrow above and not a ball, but you can't skip it and go to a single ball if the head's there.

[deathtopumpkins]

Completely unrelated to the above double-yellow ball, I discovered a signal in Massachusetts today that featured both a flashing yellow ball and steady green arrow... at the same time. Over through lanes.

It was at the entrance to a large office complex, and, since it is the weekend right now, I presume that this indication basically means that you can proceed as if it were a flashing yellow, but there's a 99.99999% chance you won't encounter any opposing movements so don't bother slowing down. If my camera battery weren't dead I would have snapped a pic, but I believe it was somewhere along a multilane portion of MA 62 west of Burlington.

[SignBridge]

Steve, thank-you...........Yes I stand corrected about the 2 yellows. Today I observed 2 different 5-stacks in my area. And in both cases where the green-ball and turn-arrow are terminated together, both the yellow-ball and yellow-arrow are displayed together. I can't believe I didn't know that........... I've deleted my previous post.

[Alps]

Completely unrelated to the above double-yellow ball, I discovered a signal in Massachusetts today that featured both a flashing yellow ball and steady green arrow... at the same time. Over through lanes.

It was at the entrance to a large office complex, and, since it is the weekend right now, I presume that this indication basically means that you can proceed as if it were a flashing yellow, but there's a 99.99999% chance you won't encounter any opposing movements so don't bother slowing down. If my camera battery weren't dead I would have snapped a pic, but I believe it was somewhere along a multilane portion of MA 62 west of Burlington.

Eh, drive around Massachusetts long enough and after seeing red balls with green through arrows, red and green balls simultaneously, flashing and solid indications simultaneously... you just get numb.

[Michael]

As I'm typing this, a construction crew is squaring off a milled area to be repaved in front of a stoplight on my street.  They have a bulldozer to help, and it was in the same position for a few minutes over the sensor loops for the stoplight in two of the three lanes (all one way, one is open).  When a line of cars came to the light, it took about 2-3 minutes for it to change to green.  I thought they damaged the loops since I've never seen it red for that long.  If a sensor loop detects something over it for an extended period of time, will it ignore the approach?

EDIT: I went back outside and saw one person drive into the coned off area (they're waiting for the asphalt), stop, then turn.  Everyone else followed, treating it as a stop sign.  As a bonus, an out of town taxi driver turned the wrong way onto my street and both one of the workers and myself went to help him get going the right way.  I walked down and pushed the crosswalk button and it turned green after about 20 seconds.  I thought that might have reset the controller, but it didn't.  I was heading back inside to call the DPW, but I saw a city SUV pull up.  I went over to talk to him, but I waited a bit longer before I did, and then pushed the button and it turned green again.  I went to talk to the guy to let him know what happened, and they were looking at a spot on the ground, so I'm guessing they damaged the sensor loops.  As another bonus, I told him I was a roadgeek and asked him if he knew what the MUTCD was.  He said yes, and I said I have a physical copy and he chuckled.

EDIT 2: I looked again, and it seems to be working normally.  Since it's past 7:00 now, I'm guessing that it might be on a different timing schedule.

While I'm talking about this light, I should post what I wanted to about it forever ago:
Has anyone here seen a stoplight have an extremely short green phase?  In the middle of the night, this light has a one second green phase for my street (which is the minor crossing) every 2 minutes or so, unless it detects traffic.  The yellow phase is the minimum 3 seconds, which ends up being longer than the green!

[jeffandnicole]

While I'm talking about this light, I should post what I wanted to about it forever ago:
Has anyone here seen a stoplight have an extremely short green phase?  In the middle of the night, this light has a one second green phase for my street (which is the minor crossing) every 2 minutes or so, unless it detects traffic.  The yellow phase is the minimum 3 seconds, which ends up being longer than the green!

NJ 29 and an office complex's parking lot in NJ, where I drop someone off in a carpool many mornings.  I call it a token green.  Since very few people are exiting in the morning, when there is a car(s) waiting to leave, there's about a 2 second green.  1 car gets thru on the green, another 2 cars can get thru on the yellow.  Anyone after that (extreme rare) either waits about 5 minutes, or runs the just-turned red light .This only occurs from about 6am - 9am. During the other 21 hours, the light operates with a more normal green cycle leaving the office complex.