Why do they need a flashing yellow arrow at all?
When turning left on a flashing yellow circle or solid green circle you yield to drivers going straight from the opposite direction so a flashing yellow arrow is redundant and just adds an element of confusion.
ETA: Hmmm. Maybe because there is no left turn without the flashing arrow?
Welcome to Panama.
I should tell you about the multi-lane roads in one direction, where one lane changes to go in the opposite direction at an intersection with no warning or signage. :eek:
Pretty much. My city has had flashing yellow arrows for a couple years so everyone who lives here knows what they mean. But you can always tell who isn’t from here by all the cars honking behind them at a flashing yellow arrow. Some people have no idea what to do, even though they all have signs saying Proceed with caution on flashing yellow arrow or similar.
On/in a lot of the left turn signals here, there are only yellow, red or green arrows. Maybe it’s a cost saving to not have the round green in those signals? No idea.
The problem with the solid green for the left turn is that it then works independently from the other lights–so if southbound straight has green, and southbound turning left has the protected green arrow, then northbound straight has a red light, but northbound turning left now has a solid green light. This sometimes confuses the people going straight, who see one solid green light and go, so they ended up doing stuff like putting tiny little blinds on the left turn green light to try and hide it from the straight lanes, etc. Just easier to switch to the flashing yellow arrow.
There’s a tremendous amount of research and discussion of left-turn control problems among traffic engineers, and has been for a long long time. There is also much information about it – including these relatively newish flashing yellow left-arrows – also on-line for the googling. Many states, and many local municipalities, have their own web sites describing this, often with animated displays of the light phases and sequencing (which can get complicated!)
There is a nationwide standard for how these signals should work, which is at least widely followed in places where this style of signals is used. But apparently that’s not done everywhere. The standard may still be emerging.
One topic that is very much discussed is the “yellow trap”, in which a left-turning car is sitting in the intersection waiting for a gap in on-coming traffic to make his turn. Then he sees the left-green light change to yellow, and knows it will turn red soon – and believes that on-coming traffic will be stopped also but they are not. This leads to the left-turning driver and the on-coming driver each thinking the other will stop, so they both go, and a collision happens.
A large motivation for the flashing-yellow-left-arrow is to solve this problem. As shown in some of the animations I’ve found, the phasing is kind of complicated. (And any one driver only sees those lights facing him, so nobody really sees the “whole picture”.)
Here are a sampling of just a few sites I found. (Googling for something like “left turn flashing yellow arrow” turns up page after page of hits.)
All About Left Turns (Traffic Signal Trivia II) – Article by Monte Castleman with some history of left-turn signals, leading to an introduction to the modern flashing yellow left arrows, including discussion of lead vs lag left turns, permissive vs protected, split phasing, and yellow trap
The Flashing Yellow Arrow and the Yellow Trap – Article by Monte Castleman, sequel to the above, with detailed discussion of modern flashing yellow left arrows and the yellow trap.
Should I Stay or Should I Go? Flashing Yellow Arrows Being Used in Bellevue – Overview (with animated gif) of the new lights with outline of the traffic rules. Note the phasing and sequencing of the lights is not entirely simple. Unfortunately, the animation only shows the lights in one direction and does not show simultaneously what lights the opposing drivers see. (If you poke around, you can find other animations that DO show this.)
FLASHING YELLOW ARROWS
CAN MAKE LEAD-LAG TRAFFIC SEQUENCES SAFE – This one does show animated gifs of many different styles and implementations of left-turn signals, and does show what the opposing drivers see at the same times. Brief discussions of how each style solves (or not) the yellow trap; but assumes the reader already knows what yellow traps are. At bottom of page are some links to further information about yellow traps, including the following among others:
Yellow Trap Index Page – Page full of links to additional information (lots and lots of, apparently) about yellow traps, including the following:
Yellow Trap Quiz – Do you know the yellow-trap danger? – Well, do you?
Anyone wanting to have an informed discussion of all this needs to read up first on some of these pages, or the myriad others that you can find out there, to be at least a bit knowledgeable as to what it’s all about. (I myself read a few pages like these, and claim to be at least some minimal bit knowledgeable about this, but not much more than that.)
Note that this is labeled as “Guidance” and not a “Standard.” Unless you have looked up the specific law in the state where you are driving, do not assume that the other road has a flashing red.
My understanding is flashing yellow lights mean the traffic lights have malfunctioned and should be treated as any other intersection (give way to your right etc), and to proceed with caution.
that’s possible but in no way safe to assume. certain intersections can have a simple, one indicator per direction signal like this one here which flashes yellow on the main road and red on the side road. it’s not malfunctioning, because that’s all it was ever intended to do.
normal signals can also be programmed to change to flashing yellow/red late at night when traffic is light; many of the signals near me do this at minor intersections.
In most cases, if the signal controller(s) detect a fault, they change to a mode which flashes red in all directions, converting the intersection into a four-way stop.
Not anywhere I’ve seen in Australia (where I live), they don’t - malfunctioning traffic lights flash yellow. Also, I’ve never seen lights here flashing late at night when there’s no traffic - they’re either on a timed cycle or they still work via induction coils under the road, as in the day.
I think it’s pretty clear the OP is in the US and a lot of the respondents are in the US, talking about a new standard implemented in the US. what does Australia have to do with anything?
If I hadn’t read about it online before I encountered it on the roads, I would have presumed that a flashing yellow arrow meant that oncoming traffic had flashing red lights. I’ve only ever encountered them at one intersection in the city of Skowhegan, Maine. Does flashing yellow actually have some advantage over just a normal green ball? After all, in either case, left turning cars must yield to oncoming cars, correct?
Yes. We still have a lot of intersections with a flashing red in the left-turn lane. It means you have to come to a stop before turning, even if there’s no oncoming traffic. A flashing yellow, though, means that I wouldn’t have to come to a complete stop first.
The new right turn lights are a bit frustrating in this regard. When none of the protected lefts are activated, the right turn lane flashes yellow. This is a good idea; it’s meant to caution you that pedestrians have the right of way in the cross walk. These lights will turn to a green arrow, too, when the opposing protected lefts activate, but importantly, they turn red for a second before switching from flashing yellow to green. I don’t really see the point of this.
Yeah, flashing yellow is step one, to clear the straight-ahead traffic in both directions, but giving you an opportunity to turn left. Usually (here), flashing yellow is followed by a green arrow.
Growing up in St. Clair County in the late 70’s and the 80’s, we had green balls.
It’s where I live, for a start. And frankly a lot of the posters here seem to need a reminder the US isn’t the only country in the world.
Also, it’s quite possible some of the folks playing along at home would find the information interesting - “Hey, they do things differently in another country”. I certainly find such tidbits useful.
Doubtful. Unless your state is unusual, right of way is something you yield, not something you or anyone else has.
where? I’ve not yet seen a right turn signal with a flashing yellow.
oh, save it please. I don’t know what it is with your lot’s pathological need to force Australia into every conversation apropos of nothing, but the OP is talking about a new(ish) standard being rolled out in the US. Your first post in this thread did nothing but add confusion since 1) it described pretty much the exact opposite of how it’s typically done in the US and 2) you failed to specify it was the done thing in Australia.
“Reminding us that Australia exists” is totally irrelevant, it adds nothing to the conversation.
This. Having a flashing yellow arrow confers no more right to turn left in the face of oncoming traffic than a flashing yellow ball does.
I remember some years ago when the Left Turn Yield on <Green Ball> signs went up in Carson City. I was in the lead car in the left lane when the light changed. The car in the left turn lane opposite started to move at the same time I did, stopped short, the young driver honked, and shook his fist at me, then proceeded to drive into the path of the guy behind me. I turned around and came back in case the hitee needed a witness. By the time I did they had pulled the two damaged autos into the parking lot and were standing by them arguing.
“But I had the right of way!”
“Well, let’s see what the cops say.”
The kid lost.
I know I’m not crazy, and I hope I’m not spreading misinformation. They’re only used when there’s a dedicated right turn lane. The intersection I’m thinking of is Groesbeck and Cass near Mt. Clemens, but I know there are a few others around.
They seem to accomplish a few things:
[ul]
[li]Eliminate the ugly “no turn on red signs” (they seem to be everywhere in Novi).[/li][li]Inform drivers that they don’t have right of way when the main signal is green, thus giving pedestrians a chance to cross. This is when it’s flashing.[/li][li]Once pedestrians can’t cross (because perpendicular traffic has protected lefts), it becomes a protected right hand turn (solid green) during a time the main traffic light might otherwise be red.[/li][/ul]
I personally like the flashing yellow lights (and roundabouts). Near where I live the city of Florence and Burlington in KY has made use of both of these and people are getting used to them.
You know what drives me nuts? Traffic lights that are on timers, especially during off hours of the day. You’ve got all this traffic going north and south and then the light turns red for the east/west side street and…there’s nobody there. So you sit and wait for nothing. Transportation departments really need to git rid of those and have the magnetic or whatever sensors installed, so the north/south light stays green on the more heavily trafficked throughway unless a car stops at the intersection going east/west. THEN the light should cycle and change.
I live not far from there, I’ll have to keep my eyes peeled next time I drive through.
some of the main roads in my area have gone to signals with adaptive timing which monitor traffic. there’s an adjustment period where people have to remember they can’t zone out on autopilot or they might miss the left turn arrow, but other than that they’re great. especially in off-peak hours where the signal turns green just as you reach the intersection 
