Traffic signal

[index]

^ The MUTCD used to show such a configuration - see Page 11/54 of https://ceprofs.civil.tamu.edu/ghawkins/MUTCD-History_files/1988%20MUTCD/4.Part_IV.Signals.pdf

Very interesting, wonder what other odd things can be found that were both uncommon, and previously permitted by the MUTCD but later removed.

[Michael]

I was driving eastbound on NY 5 in Elbridge yesterday afternoon, and I noticed something weird.  At Hamilton Road, the opposing traffic had a green ball, and what I'm assuming was a leading left.  While the eastbound ball was still red, the left turn FYA started flashing.  I thought it was weird to see something other than all red lights with oncoming traffic.  How common is this?  This was my first time ever seeing this phasing.

[SignBridge]

Ah yes.........this is what FYA is all about and why it came into existence, for just this type of situation. In some Southern states like Texas there had been a practice of using a green ball in that configuration over the left-turn lane, while the thru lanes had all reds. It was called Dallas Phasing and the FYA now replaces the green ball in that situation.

Since the introduction of the FYA, many traffic agencies have found other creative applications for the FYA, but the signal you referred to illustrates the original concept.

[Michael]

So a green arrow would be shown with an opposing green ball?!  I never quite understood Dallas Phasing, but a quick Google search shows pictures with conflicting arrows and balls.  NY has always used doghouses and most often uses leading lefts, although you sometimes see mid-phase or lagging lefts.  Green arrows are always "safe" to go through.

EDIT: I forgot to mention that the intersection used to have a two-phase signal with no turn lanes until a couple years ago.  When they added the turn lanes on NY 5, they used FYAs.  FYAs are becoming more common in NY.  The first one I saw in NY (and anywhere) was this one in 2014 or 2015.

[SignBridge]

Michael, read my post again. A green ball would be over the left-turn lane with parallel thru lanes being red. The opposing direction would have green-ball and left-turn arrow.

There were no actual conflicts in Dallas Phasing but the green-ball specifically over the left-turn lanes was misleading. People thought it meant the same as a green-arrow when it was over the turning lane while the thru lanes were red and many accidents resulted.

[kphoger]

I never quite understood Dallas Phasing

Hmm, I guess it's time to break out this video again.  When is this going to be a sticky in the Welcome forum?

This took me a little while to finish up, but I hope you all will find it helpful.  I've created a short video that explains in a graphic format the differences between the various forms of protected/permitted left turn controls, including Dallas Phasing.

By no means am I a whiz with video capture and online videos, so I hope it works okay. Here it is: http://www.youtube.com/watch?v=KPKjcPI5Sko

[Amtrakprod]

FYAs doing that do there job. It seems strange but that's how they work. I think that if drivers are going left then they should look at only their left turn signal. That avoids all confusion. That's why some states use louvers at complex intersections and of course for preventing traffic from an odd signal to see a wrong light


iPhone

[jakeroot]

I was driving eastbound on NY 5 in Elbridge yesterday afternoon, and I noticed something weird.  At Hamilton Road, the opposing traffic had a green ball, and what I'm assuming was a leading left.  While the eastbound ball was still red, the left turn FYA started flashing.  I thought it was weird to see something other than all red lights with oncoming traffic.  How common is this?  This was my first time ever seeing this phasing.

How many FYA's are there in that area? Interesting that you've never seen it before, unless your jurisdiction bans the practice (as tradephoric seems to think is a thing).

This occurs at FYA's for two reasons: (1) no vehicle in turn lane, so the FYA signal defaults to flashing, or (2) the signal is set to lead/lag (green arrow in advance for one direction, at the end for the other direction).

I feel like I've posted this video a thousand times, but I guess as long as people haven't seen it...here's an example of situation #2. My direction has a lagging green arrow, so it comes on at the end of the cycle, instead of in advance. As a result, my left turn begins with a flashing yellow arrow, but the through traffic remains red while the oncoming left has a green arrow (as you would expect).

https://youtu.be/_idz1QzWQtg

[Michael]

Michael, read my post again. A green ball would be over the left-turn lane with parallel thru lanes being red. The opposing direction would have green-ball and left-turn arrow.

There were no actual conflicts in Dallas Phasing but the green-ball specifically over the left-turn lanes was misleading. People thought it meant the same as a green-arrow when it was over the turning lane while the thru lanes were red and many accidents resulted.

Ok, gotcha.  The Google Images results showed conflicting balls and arrows.  For as long as I remember, NY has always used arrows for dedicated signal heads.

@kphoger: Thanks for the video.  I watched it several years ago to understand yellow trap, but never watched the part about Dallas Phasing.

@jakeroot: That one is the closest to me, and the only other ones I've personally seen are the one I mentioned near Binghamton in my previous post, and a pair in Oneida that were installed in the past year or two.  I drove through the ones in Oneida, but nothing seemed weird about those to me.  NYSDOT seems to be replacing doghouses with FYAs, and uses the flashing yellow to reinforce that you have to yield if you're turning left during the permitted phase.  Your video is the exact phasing I saw, but the light uses leading lefts.  It may use mid-phase or lagging lefts, but I haven't seen it use them.  For the most part, NY uses leading lefts.

In the Elbridge example, there were no cars waiting to turn left next to me, and a couple waiting in the opposite direction.  With a traditional doghouse, the opposing direction would get a green ball/left arrow, and the arrow on my side would have done nothing.  I haven't paid close attention to how often it happens, but I have seen cases where there weren't any cars going straight from the opposite direction or left from my direction, and the light gave two opposing green arrows anyway instead of through/left greens for the opposing direction.

[jakeroot]

At this intersection in unincorporated Spokane County, WA, each approach has two near-side signals. However, the near-side signals for the left-side of the intersection are on the near-side mast poles. Good for visibility when way back in a line of cars, but not so great when nearer the stop line.

Approach from US-2: https://goo.gl/maps/zmaH9VfZsAd6PqKk8 (fixed link)
Approach from side-street: https://goo.gl/maps/B8BVse8Jzkyxcm7Q7

Supplemental signals are either normal or very common in this part of WA (note the Flint Rd intersection just east), unlike some western areas of the state, but this placement is rather unusual.

[mrsman]

At this intersection in unincorporated Spokane County, WA, each approach has two near-side signals. However, the near-side signals for the left-side of the intersection are on the near-side mast poles. Good for visibility when way back in a line of cars, but not so great when nearer the stop line.

Approach from US-2: https://goo.gl/maps/hHTyHHaiMJk6bNV88
Approach from side-street: https://goo.gl/maps/B8BVse8Jzkyxcm7Q7

Supplemental signals are either normal or very common in this part of WA (note the Flint Rd intersection just east), unlike some western areas of the state, but this placement is rather unusual.

This is sort of weird.  IMO, the whole point of the left side supplemental signal is for the drivers who are turning left and need to make an uprotected left so they can focus their attention on looking at the signal while still having their eye on opposing traffic and pedestrians.  This doesn't do that.  I don't know what this accomplishes.

The right side supplemental signal's purpose is both for visibility in case you are behind a big truck and for making right turns so that you can look at the signal while watching for pedestrians.  Since your focus is not as far for right turns as it is for left turns, it is not a problem for the right signal to be on the near side.

From what I understand of typical signal placement in Wisconsin, the right side supplemental signal is on the near side and the left side supplemental signal is on the far side.  This acknowledges

[EDITED TO ADD: that the cones of vision for both turns are different.  For left turns you look for gaps in opposing traffic and are also looking at the far corner for peds.  For right turns, the focus should be on peds on the near side.  Your focus does not need to be on the far corner as much.]

As a native Californian, though, I have a bias for having both the left and right supplemental signal on the far side.

[mrsman]

So a green arrow would be shown with an opposing green ball?!  I never quite understood Dallas Phasing, but a quick Google search shows pictures with conflicting arrows and balls.  NY has always used doghouses and most often uses leading lefts, although you sometimes see mid-phase or lagging lefts.  Green arrows are always "safe" to go through.

EDIT: I forgot to mention that the intersection used to have a two-phase signal with no turn lanes until a couple years ago.  When they added the turn lanes on NY 5, they used FYAs.  FYAs are becoming more common in NY.  The first one I saw in NY (and anywhere) was this one in 2014 or 2015.

With FYAs, when the opposing side has a leading protected green, you can program the signal to allow for a permitted left turn at the same time in your direction.  Thru traffic in your direction has a red (giving the opposing left a protected turn), but the operation of the left in your direction is not affected by that.  It is a bit unusual to see this, but IMO this signaling is perfectlyl safe.  And even for those (like tradephoric) who believe in the "perceived" yellow trap situation as being a possible concern, I don't believe that exists on this side, since at teh beginning of the signal (after cross traffic's green) you see a flashing yellow arrow at the same time as red.  (I.e. no yellow trap here since you never see a yellow.)

The perceived yellow trap is only a problem for lagging protected green with permitted opposing lefts at the same time.  There, the side with the lagging protected green sees green thru and green arrow starts at the end of the signal cycle.  The opposing side will have the thru traffic see yellow orb and then red orb, while the lefts on that opposing side maintain a flashing yellow arrow.  The theory behind perceived yellow trap is that drivers turning left in the opposing direction are so used to focusing on the signaling of the orbs is that they will assume that traffic  that is opposing them (i.e. the side with the lagging left) will come to a slow and then a stop because the traffic that is next to them is doing the same thing [even though the left turners are only supposed to focus on their signal alone, the FYA]. 

I am not sure if perceived yellow trap is really significant, especially now as FYAs are becoming more common, but FWIW, it's only present on the lagging left phase, not the leading left phase.

[MNHighwayMan]

Approach from US-2: https://goo.gl/maps/hHTyHHaiMJk6bNV88
Approach from side-street: https://goo.gl/maps/B8BVse8Jzkyxcm7Q7

I think your first link is the wrong link, because it's at a different place entirely from the second, and it's not at an intersection.

[jakeroot]

Approach from US-2: https://goo.gl/maps/hHTyHHaiMJk6bNV88
Approach from side-street: https://goo.gl/maps/B8BVse8Jzkyxcm7Q7

I think your first link is the wrong link, because it's at a different place entirely from the second, and it's not at an intersection.

No idea how that happened. Guess I was working with too many links yesterday.

If you didn't already pan around using that second link, here's the correct link: https://goo.gl/maps/zmaH9VfZsAd6PqKk8

[jakeroot]

At this intersection in unincorporated Spokane County, WA, each approach has two near-side signals. However, the near-side signals for the left-side of the intersection are on the near-side mast poles. Good for visibility when way back in a line of cars, but not so great when nearer the stop line.

Approach from US-2: https://goo.gl/maps/hHTyHHaiMJk6bNV88 https://goo.gl/maps/zmaH9VfZsAd6PqKk8
Approach from side-street: https://goo.gl/maps/B8BVse8Jzkyxcm7Q7

Supplemental signals are either normal or very common in this part of WA (note the Flint Rd intersection just east), unlike some western areas of the state, but this placement is rather unusual.

This is sort of weird.  IMO, the whole point of the left side supplemental signal is for the drivers who are turning left and need to make an uprotected left so they can focus their attention on looking at the signal while still having their eye on opposing traffic and pedestrians.  This doesn't do that.  I don't know what this accomplishes.

The right side supplemental signal's purpose is both for visibility in case you are behind a big truck and for making right turns so that you can look at the signal while watching for pedestrians.  Since your focus is not as far for right turns as it is for left turns, it is not a problem for the right signal to be on the near side.

From what I understand of typical signal placement in Wisconsin, the right side supplemental signal is on the near side and the left side supplemental signal is on the far side.  This acknowledges

As a native Californian, though, I have a bias for having both the left and right supplemental signal on the far side.

I think the entire point of near-side signals is to provide supplemental displays that may assist drivers in identifying the state of a traffic light, when the far-side displays are simply too far from the stop line to be the only acceptable set of signals (this is particularly problematic on parts of the Las Vegas strip, IIRC). In this sense, I think the near-side displays in my links actually do a good job, even if the far-side displays are well within an easy-to-see distance. But they are also good in assisting drivers in identifying the state of traffic lights when the far-side signals are not visible, or when yielding to pedestrians, as you indicate. Certainly there are many uses; I wish the FHWA required them more often.

This signal may have been the result of the WSDOT team using the proposed 150-foot rule for near-side displays. Apparently, the FHWA was considering a change to the near-side signal policy requirements, moving the maximum allowable distance without a near-side display, from 180 feet, to 150 feet. In both cases at this approach, the signals are more than 150 feet from the stop line, but less than 180 feet. I believe the rule was being considered in the late 2000s, for the 2009 MUTCD, but was not implemented (this signal was installed around 2008). They obviously misinterpreted the ruling as requiring near-side displays for all movements, but I think I'll give them a pass! I still like the setup, and it's far better than using only far-side displays, even if it isn't kosher.

This sort of situation has occurred at several other locations in Washington, particularly in Vancouver and Federal Way. On both instances, when I contacted the appropriate public works departments, I was informed that the near-side displays at several intersections were used for future compliance with the 150-foot ruling. But that ruling was dropped, so those signals stand today as a testament to a proposed change that was never implemented.

edit: fixed links (again...ugh).

[mrsman]

At this intersection in unincorporated Spokane County, WA, each approach has two near-side signals. However, the near-side signals for the left-side of the intersection are on the near-side mast poles. Good for visibility when way back in a line of cars, but not so great when nearer the stop line.

Approach from US-2: https://goo.gl/maps/hHTyHHaiMJk6bNV88 https://goo.gl/maps/zmaH9VfZsAd6PqKk8
Approach from side-street: https://goo.gl/maps/B8BVse8Jzkyxcm7Q7

Supplemental signals are either normal or very common in this part of WA (note the Flint Rd intersection just east), unlike some western areas of the state, but this placement is rather unusual.

This is sort of weird.  IMO, the whole point of the left side supplemental signal is for the drivers who are turning left and need to make an uprotected left so they can focus their attention on looking at the signal while still having their eye on opposing traffic and pedestrians.  This doesn't do that.  I don't know what this accomplishes.

The right side supplemental signal's purpose is both for visibility in case you are behind a big truck and for making right turns so that you can look at the signal while watching for pedestrians.  Since your focus is not as far for right turns as it is for left turns, it is not a problem for the right signal to be on the near side.

From what I understand of typical signal placement in Wisconsin, the right side supplemental signal is on the near side and the left side supplemental signal is on the far side.  This acknowledges

As a native Californian, though, I have a bias for having both the left and right supplemental signal on the far side.

I think the entire point of near-side signals is to provide supplemental displays that may assist drivers in identifying the state of a traffic light, when the far-side displays are simply too far from the stop line to be the only acceptable set of signals (this is particularly problematic on parts of the Las Vegas strip, IIRC). In this sense, I think the near-side displays in my links actually do a good job, even if the far-side displays are well within an easy-to-see distance. But they are also good in assisting drivers in identifying the state of traffic lights when the far-side signals are not visible, or when yielding to pedestrians, as you indicate. Certainly there are many uses; I wish the FHWA required them more often.

This signal may have been the result of the WSDOT team using the proposed 150-foot rule for near-side displays. Apparently, the FHWA was considering a change to the near-side signal policy requirements, moving the maximum allowable distance without a near-side display, from 180 feet, to 150 feet. In both cases at this approach, the signals are more than 150 feet from the stop line, but less than 180 feet. I believe the rule was being considered in the late 2000s, for the 2009 MUTCD, but was not implemented (this signal was installed around 2008). They obviously misinterpreted the ruling as requiring near-side displays for all movements, but I think I'll give them a pass! I still like the setup, and it's far better than using only far-side displays, even if it isn't kosher.

This sort of situation has occurred at several other locations in Washington, particularly in Vancouver and Federal Way. On both instances, when I contacted the appropriate public works departments, I was informed that the near-side displays at several intersections were used for future compliance with the 150-foot ruling. But that ruling was dropped, so those signals stand today as a testament to a proposed change that was never implemented.

The signal in Vancouver (which BTW you've switched the links, so please correct) with both near and far right side signals (with right turn arrows).  No left side signals on the corner, but these aren't really necessary since it is a protected only left turn.  There should be no need to watch for both the signal and peds while turning.

IIRC from my days in L.A., right turn arrow signals in L.A. frequently (but not universally) occur at both near and far side on the right.  I believe part of the reason is visibility and part of the reason is following the state's rule that every signal must be shown on at least two signal faces.

[jakeroot]

The signal in Vancouver (which BTW you've switched the links, so please correct) with both near and far right side signals (with right turn arrows).  No left side signals on the corner, but these aren't really necessary since it is a protected only left turn.  There should be no need to watch for both the signal and peds while turning.

IIRC from my days in L.A., right turn arrow signals in L.A. frequently (but not universally) occur at both near and far side on the right.  I believe part of the reason is visibility and part of the reason is following the state's rule that every signal must be shown on at least two signal faces.

(fixed...I'm a mess today!)

I would appreciate a left-side repeater at all approaches, even those without yielding, as it helps in identifying the state of a traffic signal. This is mostly helpful when you cannot see the overhead signals.

California is one of the few states that I've seen that religiously uses those near and far right-side signals at all approaches. Some get close, like IL or WI, but both sometimes lack a far-side repeater (Except IL, where they are common all over Springfield). Older signals don't use them as often, but even newer signals along relatively narrow corridors have near and far right-side signals (see here in Sacramento, for example).

(for the record, I've verified both links in my post...if they still end up getting screwed up, something is wrong with Google's link-sharing service).

[Amtrakprod]

Look at this bike signal: https://www.google.com/maps/@44.9800944,-93.264005,3a,18.3y,290.55h,98.08t/data=!3m6!1e1!3m4!1sGohdyAHz_1ORjgrlrN1hNQ!2e0!7i13312!8i6656
It's a FYA Bike signal!!! https://www.google.com/maps/@44.9808745,-93.2663046,3a,16.8y,125.37h,87.03t/data=!3m6!1e1!3m4!1sWDpPpm84Hsq9tPO_7oa9Xw!2e0!7i13312!8i6656

[roadman65]

I was noticing that in San Francisco that their signals are different from the rest of the state.  Many have green (not black as other CA places use) and lack back plates (which I thought was a California requirement) and many are side mounted rather than overhead.

SF is like NYC to NY and Chicago is to IL doing their own thing different from the rest of the states they are in as far as signals go.

[Big John]

Look at this bike signal: https://www.google.com/maps/@44.9800944,-93.264005,3a,18.3y,290.55h,98.08t/data=!3m6!1e1!3m4!1sGohdyAHz_1ORjgrlrN1hNQ!2e0!7i13312!8i6656
It's a FYA Bike signal!!! https://www.google.com/maps/@44.9808745,-93.2663046,3a,16.8y,125.37h,87.03t/data=!3m6!1e1!3m4!1sWDpPpm84Hsq9tPO_7oa9Xw!2e0!7i13312!8i6656

A yellow backplate outside Canada

[mrsman]

The signal in Vancouver (which BTW you've switched the links, so please correct) with both near and far right side signals (with right turn arrows).  No left side signals on the corner, but these aren't really necessary since it is a protected only left turn.  There should be no need to watch for both the signal and peds while turning.

IIRC from my days in L.A., right turn arrow signals in L.A. frequently (but not universally) occur at both near and far side on the right.  I believe part of the reason is visibility and part of the reason is following the state's rule that every signal must be shown on at least two signal faces.

(fixed...I'm a mess today!)

I would appreciate a left-side repeater at all approaches, even those without yielding, as it helps in identifying the state of a traffic signal. This is mostly helpful when you cannot see the overhead signals.

California is one of the few states that I've seen that religiously uses those near and far right-side signals at all approaches. Some get close, like IL or WI, but both sometimes lack a far-side repeater (Except IL, where they are common all over Springfield). Older signals don't use them as often, but even newer signals along relatively narrow corridors have near and far right-side signals (see here in Sacramento, for example).

(for the record, I've verified both links in my post...if they still end up getting screwed up, something is wrong with Google's link-sharing service).

Historically, in California, many streets with medians had the far left side light on the median instead of on the far left corner.  I know that many have been removed and replaced with left corner signals because they were getting struck down by cars.  They still exist on some of the wider medians, though.

Here's an example on Sunset Blvd in SF:

https://www.google.com/maps/@37.7515473,-122.495195,3a,75y,179.42h,77.09t/data=!3m6!1e1!3m4!1stWjK1K8HQGSUdfNosAbO6w!2e0!7i16384!8i8192

[SignBridge]

I agree with Jakeroot's point that California is among the most consistent when it comes to signal configuration. Except for those near-right corner supplemental heads that he mentioned. I like them and I am puzzled by California's inconsistent use of them. Some places have them and some don't and it doesn't seem to depend on the width of the cross street either. Or on any other factor that I can identify.

[jakeroot]

I was noticing that in San Francisco that their signals are different from the rest of the state.  Many have green (not black as other CA places use) and lack back plates (which I thought was a California requirement) and many are side mounted rather than overhead.

Couple things to consider:

* [dark] green signals are/were relatively common along the West Coast (from WA to CA). They are still installed with shrinking frequency in WA.
* CA requires 'side-mounted' signals at all intersections, with very few exceptions. Overhead signals became normal only later on. In many downtown areas, there is aesthetic preference for not using overhead signals. Sometimes to reduce clutter. Other times, because of conflicts with trolley wire, power lines, etc.

Historically, in California, many streets with medians had the far left side light on the median instead of on the far left corner.  I know that many have been removed and replaced with left corner signals because they were getting struck down by cars.  They still exist on some of the wider medians, though.

It is rather interesting how many US states have shied away from median-mounted signals. They are still the norm in British Columbia; the standard setup for a dedicated left turn signal is very similar to the older CA style, except that an additional (third) signal is also mounted on the far left corner (three are required for all left turns).

I agree with Jakeroot's point that California is among the most consistent when it comes to signal configuration. Except for those near-right corner supplemental heads that he mentioned. I like them and I am puzzled by California's inconsistent use of them. Some places have them and some don't and it doesn't seem to depend on the width of the cross street either. Or on any other factor that I can identify.

It seems that newer signals always include that near-right signal. I can't immediately think of any newer signals that don't have them.

[RestrictOnTheHanger]

Ran into a few interesting signals during a roadtrip out west.

This FYA in Utah stays red for 1 to 2 seconds after the opposing thru turns green before going to flashing yellow. I dont think I saw a green arrow operational while I was there.

Side note - Utah has the best signal setups I have seen.

Meanwhile this FYA in Arizona has green in the middle.

Finally, a lot of Arizona intersections seem to have both bimodal and 5 stack turn signals mixed in the same intersection. Wonder why that is/was

Fixed links -Ian

[kphoger]

Ran into a few interesting signals during a roadtrip out west.

This FYA in Utah stays red for 1 to 2 seconds after the opposing thru turns green before going to flashing yellow. I dont think I saw a green arrow operational while I was there.

Side note - Utah has the best signal setups I have seen.

Meanwhile this FYA in Arizona has green in the middle.

Finally, a lot of Arizona intersections seem to have both bimodal and 5 stack turn signals mixed in the same intersection. Wonder why that is/was

Fixed your links for you.