In a discussion on another board about how to proceed at an intersection where the traffic light is flashing yellow, a couple of people claimed to have seen lights flashing yellow in all directions. I have only ever seen yellow/red (i.e. traffic for one direction-- e-w or n-s --has yellow and cross traffic has red) or all red, and it’s always been my assumption that that is built in to their design, since the usual driver’s ed instruction is to proceed with caution on a flashing yellow and stop on flashing red. Google isn’t helping me much here, so I’m hoping we have somebody here who actually knows something about this. I don’t know enough about how traffic signals work to really argue this point, so is it possible for a malfunctioning light to flash yellow/yellow rather than yellow/red or red/red? I’m sure there could be some massive malfunction that could cause pretty much anything to happen, but I mean in the most likely malfunction conditions, is it possible?
There is no reason lights in all directions couldn’t flash yellow all at the same time. I can’t see a city setting them up to do that, because as you noted only one road should have flashing yellow. Different light models will have their specific abilities. There is no standard controller that all lights must use. The mayor in Portage had complained this summer that three of the lights couldn’t be set up a certain way because of their hardware. They are being replaced with ones that can do what is wanted.
I can think of an outstanding reason why one should not have four-way-flashing-yellow, given most states’ traffic laws: Flashing yellow normally indicates that you have the right of way but are entering a situation of above-normal danger, so proceed cautiously. Hence, flashing yellow all four ways would tell motorists entering an intersection from all directions that they had the right of way over crossing traffic but that caution was indicated.
He means a physical reason, Poly.
I’d say that in many cases, there would be a physical reason built into the controlling software. It wouldn’t be a good idea, so they program the controller to not allow it. (Idiot proofing, though a good idiot can always find a way around things.) With the right controlling hardware/software, there would be no physical reason that it can’t be done, but with the default, it’s likely impossible.
If a site needs a permanent 4x flashing yellow, it would generally have only that yellow light, and have stop signs on at least 2 of the streets entering the intersection. In my neck of the woods, there are many intersections with a 4-way light to let you know that there is reason for caution, but not enough need for a full signal.
Well, true, BUT:
If you are approaching an intersection with a flashing yellow, you are not supposed to simply drive through it as if it was a green light, despite the fact this is what most people do. It means you slow down, look as you approach, and make certain that the way through is uncontested. If someone from the side is approaching and not stopping, prudence dictates not entering the intersection.
I’ve seen residential intersections where there is no stop sign in either direction, only yield signs. The effect is the same.
From a practical standpoint, I seriously doubt that any city would purposefully set up an intersection with flashing yellows in both directions. The potential liability would be significant.
But again–have you seen such an intersection with yield signs for both streets? IME, one crossing street has a yield sign and the other has nothing, because the second street has right-of-way. Yield signs on all corners would indicate to each driver that the other driver has right-of-way, which doesn’t make sense …
I’ve seen four way flashing yellows many times. They used to have quite a few of them in the town where I grew up. They would function as normal traffic lights during the day, then would switch over to flashing yellow at night. Keep in mind this is a small town where at 1 am you are lucky to have 1 or 2 cars out in the entire town, and the chances of you even seeing another car at an intersection late at night are pretty small.
The other case where I’ve seen it is when mutliple lights are all controlled from a single location, such as synchronized lights in large cities. If the main controller goes down (like there’s a power outage or some speeding moron takes down a utility pole), the individual intersections still have controllers, but since they can’t talk to the main controller, they go into a flashing yellow pattern. These are usually programmable, so they might do yellow in all four directions, or, more likely, they’ll do yellow in two directions and red in the other two, with the yellows used on the directions that gets more traffic. They may even go into an unsynchronized mode where they still do the green-yellow-red thing. It all depends on how the traffic engineer decided they should be programmed.
Yes, I have seen such an intersection. I said so in my last post. :smack:
No, you didn’t. Not in a way which was clearly understood.
Ah, I see what you mean. :smack:
Makes me think of Horton: “I meant what I said, and I said what I meant.”
Riiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiight…
Interesting; I’ve always lived in fairly busy suburban/urban locales and had never encountered a yellow/yellow that I could recall. The discussion this question sprang from takes place in the Atlanta area, so I would not expect to see many of those around here–a flashing light at all is usually a malfunctioning one.
A lot of drivers around here tend to try to be a little too courteous or cautious, and everybody friggin’ stops at the flashing yellow and traffic backs up forever. Some of the posters in the thread are asserting, “But the light might also be yellow in the other direction! You have to treat it as a four-way stop!” so I figured I’d spoil their gabfest with a few facts if I could (including pointing out the the official GA state driver’s manual says to proceed with caution on a flashing yellow, not stop).
The only place I can imagine 4 way yellow, or yield signs all round, is on a roundabout/traffic circle. I’ve seen, in older residential neighborhoods, where there were no traffic contols, at all, of some interesections. The speed limits are usually very low, visibility is unobstructed and the “thoroughfair”, is often obvious, meaning that side streets must stop even though there are no signs, or signals.
Like engineer_comp_geek I have seen it many times as well. All three of the red lights in my home town switched over to flashing yellows in all directions at 9 pm every night. That is pretty common in very small towns at least in the South. Of course, the reason that was a workable plan was that there just weren’t many cars out then.
New signals also flash yellow/yellow for a period of time before they are put on-line. This is to alert drivers in the area that “hey, there’s a new signal going up here! Be prepared to stop when we turn them on next week!”. Perhaps this was seen in a part of Atlanta which is seeing some growth, thus new signal?
I’m not from Missouri, but since this is GQ you’re going to have to show me anyway. No local govt. entity is going to permit such a negligent situation to exist. I don’t care how small and isolated a community is, sooner or later there’s going to be an accident caused by such a circumstance and the local taxpayers are going to be holding the bag for any findings of liability. I’ve got more miles behind a steering wheel than most Dopers and I’ve driven through thousands of burgs, I’ve seen some pretty screwy traffic patterns, but I’ve never seen an straight intersection w/ a 4 way yellow flasher.
I think you folks are either color blind, gettin’ a bit forgetful, or just talkin’ through your hats.
How is a traffic signal flashing yellow in all directions any more negligent than an intersection with no traffic signal at all? You might be surprised to hear that those still exist in some places, too, despite not requiring anyone to stop.
As I stated in an earlier post, I’ve seen intersections w/ no control, but that leaves it up to the driver to exercise caution and yield right of way. Placing a misleading traffic control device is a positive act that directly misleads drivers into believing that the have the right of way.
As I stated previously, a flashing yellow does NOT tell you you have the unimpeded right of way. It tells you to approach the intersection with caution, and not to enter it unless certain you are able to drive through without problems.
I know people don’t treat them that way, but that’s what they mean.
If anyone cares, flashing yellow in all directions is normal error/fallback/disabled traffic light behaviour in Europe (at least in my parts). The message is (freely put) “Proceed as if there were no lights at all, but with caution, as something is definitely up”.
Not that this has much to do with the discussion here (as the OP is about U.S. lights), but beware of this when googleing or collecting anecdotes.