Has the flashing yellow left turn signal made it to your state?

[jeffandnicole]

Sorry for potentially stating the obvious, but is the point of this FYA to allow left turning traffic the same benefits as turning left at a green light when oncoming traffic has cleared?

Yes.

[mukade]

Sorry for potentially stating the obvious, but is the point of this FYA to allow left turning traffic the same benefits as turning left at a green light when oncoming traffic has cleared?

Yes.

...but with an added level of confusion for many drivers.

[cl94]

Sorry for potentially stating the obvious, but is the point of this FYA to allow left turning traffic the same benefits as turning left at a green light when oncoming traffic has cleared?

Yes.

...but with an added level of confusion for many drivers.

It'll probably become more understood in a couple of years. It's certainly better than each state having its own PPLT setup.

[Aerobird]

After looking through all this, I finally figured out the "yellow trap" issue...but I'm now confused as to why this isn't resolved by simply having the signal phasing not create the "yellow trap" in the first place, instead of creating an entirely new signal type?

Problem: A yellow signal in one direction when the other direction remains green.
Logical solution: Don't have a signal phase when there is a yellow signal in one direction while the other direction remains green.
FHWA solution: Study the problem and then create a new signal phase.

I honestly can't say I've ever encountered a "yellow trapped" signal; the signals always in my experience go through the full cycle, even when there isn't opposing traffic, avoiding the issue altogether. The only "trailing" left-turn phases I've encountered have been at fully protected signals.

[Rothman]

I honestly can't say I've ever encountered a "yellow trapped" signal; the signals always in my experience go through the full cycle, even when there isn't opposing traffic, avoiding the issue altogether. The only "trailing" left-turn phases I've encountered have been at fully protected signals.

There's one in the Capital Region of NY at New Karner Rd and Albany St.  The trap is NB on New Karner.

[cl94]

I honestly can't say I've ever encountered a "yellow trapped" signal; the signals always in my experience go through the full cycle, even when there isn't opposing traffic, avoiding the issue altogether. The only "trailing" left-turn phases I've encountered have been at fully protected signals.

There's one in the Capital Region of NY at New Karner Rd and Albany St.  The trap is NB on New Karner.

There are a couple more in Saratoga and Warren Counties. I think there's at least one on NY 254.

[UCFKnights]

After looking through all this, I finally figured out the "yellow trap" issue...but I'm now confused as to why this isn't resolved by simply having the signal phasing not create the "yellow trap" in the first place, instead of creating an entirely new signal type?

Problem: A yellow signal in one direction when the other direction remains green.
Logical solution: Don't have a signal phase when there is a yellow signal in one direction while the other direction remains green.
FHWA solution: Study the problem and then create a new signal phase.

I honestly can't say I've ever encountered a "yellow trapped" signal; the signals always in my experience go through the full cycle, even when there isn't opposing traffic, avoiding the issue altogether. The only "trailing" left-turn phases I've encountered have been at fully protected signals.

while thats the easiest solution, often times traffic flow can be improved by having the protected portion at the end of the cycle due to signal timings (it also has the added benefit of often getting to skip that phase entirely during lighter traffic)

[roadfro]

Sorry for potentially stating the obvious, but is the point of this FYA to allow left turning traffic the same benefits as turning left at a green light when oncoming traffic has cleared?

Yes.

...but with an added level of confusion for many drivers.

...and an added level of comprehension and compliance for other drivers.

[roadfro]

After looking through all this, I finally figured out the "yellow trap" issue...but I'm now confused as to why this isn't resolved by simply having the signal phasing not create the "yellow trap" in the first place, instead of creating an entirely new signal type?

Problem: A yellow signal in one direction when the other direction remains green.
Logical solution: Don't have a signal phase when there is a yellow signal in one direction while the other direction remains green.
FHWA solution: Study the problem and then create a new signal phase.

The yellow trap issue is encountered when you combine lead/lag protected left turn phasing at locations where you want to have protected and permitted left turn phasing available via the traditional 5-section PPLT display. Without some modification to the standard 5-section signal head operation, implementing lead/lag left turns results in the yellow trap situation. I created a PowerPoint animation about 5 years ago that demonstrates the differences: https://www.youtube.com/watch?v=KPKjcPI5Sko

Lead/lag left turn phasing is often more desirable when coordinated signal timing is in place along an arterial. With one direction having left turns leading and the other direction trailing, you get better two-way signal progression.


The FHWA didn't create a new signal type specifically for this situation (the FYA was actually developed in Reno). A signal phasing problem existed that then-current standards didn't adequately address and several agencies had developed their own workarounds for, so FHWA initiated a study and adopted a new signal standard which addressed the problem.

[cu2010]

There is one now up at the intersection of NY190 and NY374 outside of Plattsburgh... The first I've seen in R7.

It's a bit confusing though, as there's no sign explaining what the flashing yellow arrow actually means!

They also reused the existing spanwires...also odd considering that R7 has gone to mast arms!

[empirestate]

OK, I'm finally jumping into this thread on page 28, having always passed it over because I'd never encountered the FYA. But the other day I thought I'd better look up what FYA means in case I ever did see it, and a couple of days later I did indeed find my first one. (It was one of the NYC right-turn-only installations mentioned earlier in the thread, this time at 10th Avenue and 19th Street in Manhattan.)

My first concern, as has already been discussed, was the apparent conflict in meaning between FYA and every other flashing yellow (circular) indication I've ever seen–really, any yellow indication of any kind, flashing or no. That is, I should proceed with caution but I have the right-of-way; or, at the very least, I can expect no conflicting traffic that has priority over me, barring some outlying hazard that I should watch out for.

Others have pointed out that the meaning doesn't change, in fact, and that it's because I'm turning across traffic that the conflict comes about, and so I must yield my right-of-way to oncoming vehicles–and this is true for all the other flashing (or steady) yellow indications I've described as well. I can see this side of it also, and perhaps right there is the biggest obstacle to comprehension: that there are two ways this signal can be interpreted; it's not unambiguous.

Still, many of you have reported that driver comprehension is actually best for this indication, as compared to other variations that were considered. I agree that, had I never encountered any other type of flashing yellow signal, I think I would intuitively interpret it to mean what it's supposed to mean. But because of my prior experience with flashing yellow signals (such as caution beacons, "night mode" flashers with a two-way flashing red for cross traffic, or emergency signals), my first instinct would now be to assume greater protection than I actually have, or at the very least to suffer a few moments of indecision.

What I think it comes down to, and which I don't think has been addressed yet with respect to FYA, is the question of the meaning conveyed not by the color or the flashing of the aspect, but by the arrow shape itself. This can be interpreted one of two subtly different ways:

1) The rules for the roadway as a whole still apply, but are being directed only at motorists making the indicated movement.

2) The rules normally applied to the roadway as a whole are themselves being more more narrowly applied to the indicated movement.

This discrepancy is already familiar with red arrow indications and the question of whether they permit a right turn on red. In option (1), the motorist facing a red right arrow may turn after stopping, because this is the usual rule for the roadway as a whole. But in option (2), the usual rule that red means "stop until the light is green" is being narrowly applied to the right turn movement; so, if you're facing that signal, you stop, and you can't turn right until you have a green light.

To apply this to FYA, then, in option (1) the motorist must proceed with added caution, and has the right-of-way unless turning across conflicting traffic (which would be everyone facing that signal). But in option (2), the general expectation that you should proceed with caution, but can expect no conflicting traffic, is being specifically applied to the turning movement.

I'm guessing that for red arrows, most jurisdictions apply (1) and allow the right on red, but there are plenty of places where (2) takes precedence instead. For yellow signals, I think the overriding assumption is also (1), but those motorists who are accustomed to (2) may expect it to apply here as well. So it seems that if we could just agree on whether (1) or (2) is the true test of an arrow signal's meaning, we could eliminate the confusion (barring the fact that this may be a more complex line of thinking than motorists should ideally have to undertake while driving).

But here's the kicker: if we apply these tests to green arrows, then under option (1), motorists making the turn would have to yield to oncoming traffic, because overall, a green signal means proceed with right-of-way unless turning across traffic, which all of these motorists are. But under option (2), which is universally applied in the U.S., a green arrow means you may proceed and have the right-of-way with no conflicts for your specific movement; i.e., the left turn.

So in other words, if a FYA means yield to oncoming traffic, then a green arrow does too (and a red arrow means you can turn on red). But under long-established actual practice, a green arrow means go, free and clear; therefore, a yellow arrow means go, clear but with caution, and if flashing, this indication is ongoing rather than transitional (and a red arrow means no turn on red).

tl;dr: What a flashing yellow arrow means depends on three things: 1) what yellow means, 2) what flashing means, and 3) what an arrow means. So far, we haven't standardized all three, so the meaning remains intrinsically unclear.

[cl94]

I mentioned this in the New York thread, but more FYAs from NYSDOT. Region 4 installed a bunch in Auburn, both the 4-section left turn and 3-section right turn varieties.

NYSDOT Region 1 will be installing them in Rensselaer, Saratoga and Washington Counties this Fall. One FYA was recently installed on NY 146 in Halfmoon.

Still no word from Region 5.

[Ace10]

<snip>
tl;dr: What a flashing yellow arrow means depends on three things: 1) what yellow means, 2) what flashing means, and 3) what an arrow means. So far, we haven't standardized all three, so the meaning remains intrinsically unclear.

Great write-up! I'd agree that there's not a universal blanket meaning placed on signal color or shape (or even solid/flashing operation), like you state. It all depends on a combination of the three as well as the context of the intersection in question and even what state you're in as far as what you can legally do in each case.

My take is, if you encountered an intersection of two two-way streets with one way flashing circular yellow and the other flashing circular red, and you're approaching facing the flashing yellow signals, how you approach that intersection depends on what way you plan to move through it. If you're going straight, you generally have the right of way (cross traffic has flashing red and needs to yield). However, if you're turning left, you should already know you need to yield to oncoming traffic.

The FYA means exactly the same thing to left-turning traffic as in the above example-they need to yield to oncoming traffic and pedestrians-but the FYA is able to do so both in normal operation and apply its meaning to left turning drivers only while separate signals control separate movements. It is impossible for a standard* doghouse signal to show both a permissive (not protected) signal to turn left while at the same time showing a circular red for through traffic to stop. Before the FYA (I believe) there was no way to indicate a permissive left turn independent of through traffic when all signals were visible to all drivers.

Of course this logic falls apart with flashing yellow right arrows. In the circular yellow example, you'd generally also have the right of way except for needing to yield to pedestrians when turning; however, if you meet a flashing yellow right arrow, there are either pedestrians to whom you must yield or cross traffic coming from your left. In the circular red/yellow example, this cross traffic would have a flashing red and need to stop; however, in the normal operation of a flashing yellow right arrow, traffic could be coming from your left in the cross street. So in this regard a flashing yellow right arrow is more different from a circular yellow than a flashing yellow left arrow is from the same circular yellow. Flashing yellow right arrow means there might be cross traffic coming from the left, while at the same time a flashing yellow left arrow means there is oncoming traffic but there shouldn't be cross traffic coming from your right - unless a state wants to get really bold and allow permissive lefts (without stopping) when there is cross traffic.

So now it depends on signal color, shape, solid/flashing, and even what direction (left or right) the arrow is pointing which determines not only what you can do but from where you can expect there to be conflicting traffic. Fun, eh?

However, I'd advocate for what I've seen Minnesota do at almost every FYA they have - post a sign that states something along the lines of "Left turn yield on flashing yellow arrow". (I'd also absolutely love similar signs here in Oregon and Washington that state "After stop left turn on red permitted" for all left turns onto one-way streets, especially those from two-way streets. People on this forum must know I have an axe to grind with that since I've seen only one other person make a left on red from a two-way to one-way around here and wish more people would know about and do the move when it's safe to do so.)

*Standard in this case means one not specially programmed to display a flashing yellow arrow indication. I know some signals exist which can do this. I'm talking about ones that can only display solid arrows and show a solid circular green to indicate permissive movement for left turning traffic and through movement for through traffic.

[jakeroot]

(I'd also absolutely love similar signs here in Oregon and Washington that state "After stop left turn on red permitted" for all left turns onto one-way streets, especially those from two-way streets. People on this forum must know I have an axe to grind with that since I've seen only one other person make a left on red from a two-way to one-way around here and wish more people would know about and do the move when it's safe to do so.)

I concur. Luckily, I know of at least one situation where there is such a sign. Montlake @ Hamlin in Seattle. Hamlin runs one-way in opposite directions from Montlake, so both left turn lanes have this sign (hence why you can see another left turn lane in the background). They're both technically left turns onto one-ways:

[Ace10]

(I'd also absolutely love similar signs here in Oregon and Washington that state "After stop left turn on red permitted" for all left turns onto one-way streets, especially those from two-way streets. People on this forum must know I have an axe to grind with that since I've seen only one other person make a left on red from a two-way to one-way around here and wish more people would know about and do the move when it's safe to do so.)

I concur. Luckily, I know of at least one situation where there is such a sign. Montlake @ Hamlin in Seattle. Hamlin runs one-way in opposite directions from Montlake, so both left turn lanes have this sign (hence why you can see another left turn lane in the background). They're both technically left turns onto one-ways:

Wow, how did I miss seeing this sign?! I was last in that area a little over 3 years ago so I don't know if those signs were posted back then, but I would have definitely done a double take when seeing it.

I also don't think I've ever seen any indication (out in the field or in RCW) where a U-turn on red is permitted. The only one I've seen so far is that image you posted, and while it doesn't mean a U-turn on red is legal everywhere in WA (I highly doubt it is) at least it is at that one intersection. However the U-turn here kinda makes sense because in order to get onto SR 520 westbound from Montlake northbound, or from SR 520 westbound onto Montlake southbound, you have to make that U-turn there, and it probably helps cut down on traffic allowing drivers to make the left on red there.

Also I found it interesting that the signal that faces northbound traffic is an arrow, yet the sign shows a red circle. https://www.google.com/maps/@47.6455593,-122.3044832,3a,27.2y,327.33h,106.98t/data=!3m6!1e1!3m4!1s6JAjZZZ_UnKiBFeB70bnfQ!2e0!7i13312!8i6656

[jakeroot]

I also don't think I've ever seen any indication (out in the field or in RCW) where a U-turn on red is permitted. The only one I've seen so far is that image you posted, and while it doesn't mean a U-turn on red is legal everywhere in WA (I highly doubt it is) at least it is at that one intersection. However the U-turn here kinda makes sense because in order to get onto SR 520 westbound from Montlake northbound, or from SR 520 westbound onto Montlake southbound, you have to make that U-turn there, and it probably helps cut down on traffic allowing drivers to make the left on red there.

It's a very heavily used left turn/u-turn going northbound on Montlake for the exact reasons you've stated. If they didn't have the signs I'm sure traffic would back-up pretty horrendously. As far as a U-turn on red, indeed this is the only example that I'm aware of anywhere in Washington or Oregon, or really the whole of the US. I'm going to post this to the "unique odd or interesting" thread to see if anyone else has seen this before.

Also I found it interesting that the signal that faces northbound traffic is an arrow, yet the sign shows a red circle. https://www.google.com/maps/@47.6455593,-122.3044832,3a,27.2y,327.33h,106.98t/data=!3m6!1e1!3m4!1s6JAjZZZ_UnKiBFeB70bnfQ!2e0!7i13312!8i6656

Also interesting is that they replaced the signal a few years ago. I'm surprised they didn't replace the signal with an FYA, since Seattle has them all over the place now.

[Ace10]

Also interesting is that they replaced the signal a few years ago. I'm surprised they didn't replace the signal with an FYA, since Seattle has them all over the place now.

Hmm... I wonder if SDOT (or whoever is responsible for maintaining the signal/intersection) thought it was unsafe to allow permissive U-turns without stopping, given such turns are made much more slowly, and since there is a lot of U-turning traffic, could present a problem for oncoming traffic that need to slow down in case a bunch of U-turners just blindly follow each other on the FYA without checking for oncoming traffic. The red arrow at least legally requires them to stop, and the green arrow protects the movements.

Of course, permissive U-turns are allowed at virtually every other intersection in Washington (except where prohibited by signs) given that Washington I believe has no general prohibition of U-turns at traffic signals. So if Washington can allow U-turns at any old green light, why can't it here with a FYA?

(That's also the only major difference I've found between Washington and Oregon's traffic laws, that Washington generally allows U-turns at signals (and anywhere else along a flat, straight road) and Oregon generally prohibits them at signals. Everything else down to marked/unmarked crosswalks and turning at red signals (circular or arrow) is the same between them it seems. Thankfully Oregon does allow U-turns within city limits at unsignalized intersections which I've had to take advantage of from time to time. Still doesn't stop the many drivers I see illegally make the U-turn at signals in Oregon when no sign permitting the turn is there.)

[GaryV]

tl;dr: What a flashing yellow arrow means depends on three things: 1) what yellow means, 2) what flashing means, and 3) what an arrow means. So far, we haven't standardized all three, so the meaning remains intrinsically unclear.

Good summary. 

We've had this discussion before, maybe in this thread. The problem is that there is no signal for "yield" - only for stop, about to stop, or go.  They had to make up something for a left turn signal.  FYA that doesn't mean go turned out to be the accepted standard.  (As opposed to the MI and maybe other implementations of a flashing red ball that doesn't mean stop.)

[wisvishr0]

tl;dr: What a flashing yellow arrow means depends on three things: 1) what yellow means, 2) what flashing means, and 3) what an arrow means. So far, we haven't standardized all three, so the meaning remains intrinsically unclear.

Oh. My. God. You have summed up ALL the issues I've had with flashing yellows (and the reasons for me having those issues) in one comprehensive, concise and easy to understand exposition. You. Are. Amazing.

Maryland doesn't have flashing yellow left arrows, and here, you're not allowed to turn right on a red arrow, so I've ALWAYS interpreted signals through paradigm number (2) in your write-up. It just meshes with *my* experiences as a driver in Maryland. I realized that other people have had other experiences that make them think otherwise, so I stepped out of the discussion earlier this year.

I'm reiterating a point I made earlier, but I think there *is* one silver-bullet that *could've* prevented this ambiguity, at least when interpreting signals through option (2): using flashing green orbs to replace flashing yellow orbs (i.e. you have the right of way if you're going straight, but people might try to turn across the intersection in front of you, and you might have to stop for pedestrians). That would free up flashing yellow to mean "yield to all other vehicles and pedestrians," which actually could have a lot of applications even beyond permissive left turns.

Unfortunately, it's too late for that. Flashing green is already used in some places (e.g. British Columbia and Quebec) to mean different things. And "demoting" flashing yellow signals could have disastrous consequences, as people might still think they have the right of way on approaching them.

Right now, I think the best solution is to require that all states put up signs at all flashing yellow lefts explaining that you have to yield, as Ace10 suggested. *Sigh...* I wish we lived in a more perfect world.

Of course, my entire post falls apart when looking at it through option (1), which is still a valid interpretation. But if option (1) is valid, we'd need a more logical way to portray protected left turns, as you mentioned. So bleargh, this is just a really messy issue that doesn't have an elegant solution.

[jakeroot]

I've always maintained that driving requires some degree of intuition. Whether or not this can applied to the issue here (as far as how an FYA can be interpreted), I'm unsure. On one hand, context is extremely important to any situation, and signals based on context (meanings those which depend on the environment) shouldn't cause an issue; a flashing yellow arrow above your lane should mean "yield in the direction pointed", even if flashing yellow means something else entirely at another intersection. But on the other hand, a signal with two meanings, is, in the best use of the word, a bit misleading.

[tradephoric]

But on the other hand, a signal with two meanings, is, in the best use of the word, a bit misleading.

Another example of a signal indication with two different meanings... the alternating flashing red ball.  This is what Michigan's drivers are taught to do for each situation (Source: Michigan's What Every Driver Must Know SOS handbook).   

Railroad crossing:  Stop when the balls are ringing, the lights are flashing or the gate is down or in motion.  Do not drive through, around or under any railroad crossing system.

Schoolbus:  When the red overhead lights are flashing, stop at least 20 feet from the school bus. Remain stopped until the flashing red lights are turned off or the bus resumes its travels. 

HAWK:  Alternating flashing red — Stop and proceed only when clear.

[empirestate]

Stop when the balls are ringing

That's what she said.

[jakeroot]

Stop when the balls are ringing

That's what she said.

[Super Mateo]

After looking through all this, I finally figured out the "yellow trap" issue...but I'm now confused as to why this isn't resolved by simply having the signal phasing not create the "yellow trap" in the first place, instead of creating an entirely new signal type?

Problem: A yellow signal in one direction when the other direction remains green.
Logical solution: Don't have a signal phase when there is a yellow signal in one direction while the other direction remains green.
FHWA solution: Study the problem and then create a new signal phase.

I honestly can't say I've ever encountered a "yellow trapped" signal; the signals always in my experience go through the full cycle, even when there isn't opposing traffic, avoiding the issue altogether. The only "trailing" left-turn phases I've encountered have been at fully protected signals.

The only places this happens on the IL side of Chicagoland is either adjacent to a railroad track or when a series of lights are so close to each other that they are timed together.  They are accompanied by "Oncoming Traffic Has Longer Green" signs.

I did see the FYA on US 6 in NW IN the other day.  I was stopped on the side with the leading left.  The other side had lagging, and the driver with the FYA didn't know what to do, so she just went into reverse back into the turning lane. (No one was behind her.)

I get what FYA's are supposed to do.  I just don't see why they're necessary.  If you want lagging lefts, or yellow trap is a problem, then use protected turns only.

[mrsman]

tl;dr: What a flashing yellow arrow means depends on three things: 1) what yellow means, 2) what flashing means, and 3) what an arrow means. So far, we haven't standardized all three, so the meaning remains intrinsically unclear.

Oh. My. God. You have summed up ALL the issues I've had with flashing yellows (and the reasons for me having those issues) in one comprehensive, concise and easy to understand exposition. You. Are. Amazing.

Maryland doesn't have flashing yellow left arrows, and here, you're not allowed to turn right on a red arrow, so I've ALWAYS interpreted signals through paradigm number (2) in your write-up. It just meshes with *my* experiences as a driver in Maryland. I realized that other people have had other experiences that make them think otherwise, so I stepped out of the discussion earlier this year.

I'm reiterating a point I made earlier, but I think there *is* one silver-bullet that *could've* prevented this ambiguity, at least when interpreting signals through option (2): using flashing green orbs to replace flashing yellow orbs (i.e. you have the right of way if you're going straight, but people might try to turn across the intersection in front of you, and you might have to stop for pedestrians). That would free up flashing yellow to mean "yield to all other vehicles and pedestrians," which actually could have a lot of applications even beyond permissive left turns.

Unfortunately, it's too late for that. Flashing green is already used in some places (e.g. British Columbia and Quebec) to mean different things. And "demoting" flashing yellow signals could have disastrous consequences, as people might still think they have the right of way on approaching them.

Right now, I think the best solution is to require that all states put up signs at all flashing yellow lefts explaining that you have to yield, as Ace10 suggested. *Sigh...* I wish we lived in a more perfect world.

Of course, my entire post falls apart when looking at it through option (1), which is still a valid interpretation. But if option (1) is valid, we'd need a more logical way to portray protected left turns, as you mentioned. So bleargh, this is just a really messy issue that doesn't have an elegant solution.

I also tend to agree with the above.  It seems that to provide signal indications that are not yet standardized, the highway department needs to define their own meaning, even if it lacks consistency.

These are the usual meanings for the following signals in the US.  Unfortunately, even this is not consistent among all 50 states.  I advocate for one meaning for each signal and if there is an exception, even the exception applies statewide in your state but not in other states, it must be clearly signed.  For example most states do not allow left on red, except one-way to one-way.  But for the states that do allow it, put it in a sign.

1)solild red ball - stop and wait to go straight or turn left (exc. one-way to one-way).  right turn on red permitted after stop.
2)solid yellow ball - slow down.  light will soon change to red
3)solid green ball - proceed.  unless there are arrow indications, yield to on-coming traffic on left turns and yield to pedestrians on right turns.

4)flashing red ball - STOP sign equivalent.  stop and proceed when clear.  the other street has the right of way, unless this is a 4-way stop when you will alternate turns

5)flashing yellow ball - some form of caution.  Usually informs you of an intersection where you have right of way and other street has a stop sign

flashing green ball - no meaning in US

??? - YIELD sign equivalent (no current indication for YIELD for straight thru traffic

6)solid red arrow - stop and wait to make the turn.  No turn on red arrow.
7)solid yellow arrow - slow down.  light will soon change to red
8)solid green arrow - proceed.  you have the right of way over any other conflicting car or pedestrian movement* to make the indicated turn. 

9)flashing red arrow - STOP sign equivalent.  stop and proceed when clear.  Flashing red left arrow: STOP and then proceed with turn while yielding to oncoming traffic.  Flashing red right arrow: STOP and the proceed with turn while yielding to pedestrians and/or traffic on the street you're turning onto. 

10) flashing yellow arrow - YIELD sign equivalent for turns.  Full stop not required.  Flashing yellow left arrow: Yield to oncoming traffic before proceeding with turn.  Flashing yellow right arrow: YIELD and then proceed with turn while yielding to pedestrians and/or traffic on the street you're turning onto.

flashing green arrow - no meaning in US

So essentially, we have to memorize 10 inconsistent signal indications.