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  #1  
Old 06-01-2010, 11:12 PM
SenorBeef SenorBeef is online now
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What is the purpose of "turn on green arrow only" signs?

Very frequently there will be a multilane road with a left hand exit lane with a stoplight. There will be a sign hanging next to the left lane's light which says "turn on green arrow only" or something like that.

But the thing is - the only states that leftmost light has is red, yellow, and a green arrow. They never ever just have a plain green light. There is never a situation in which you would alter your behavior because of that sign.

So why are they there?
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  #2  
Old 06-01-2010, 11:16 PM
mhendo mhendo is online now
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I assume they are there to ensure that people don't turn left on a red light.

That is, they warn drivers that, just because the lanes to their right have a green light to go straight ahead, the cars in the turning lanes are not allowed to turn left, even if there is no oncoming traffic, until the green arrow comes on.

Last edited by mhendo; 06-01-2010 at 11:16 PM..
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Old 06-01-2010, 11:22 PM
SenorBeef SenorBeef is online now
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I guess that's a logical interpretation, but it seems unnecesary. If the light for your lane is red, you don't go anywhere, that's obvious. You might as well put a sign on top of every normal stoplight that says "do not go through intersection on red" just in case people forget.
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Old 06-01-2010, 11:29 PM
mhendo mhendo is online now
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I agree with you but, having been on the roads for more than 20 years, i've learned not to overestimate the intelligence of the average driver.
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Old 06-01-2010, 11:49 PM
IAmNotSpartacus IAmNotSpartacus is offline
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Originally Posted by mhendo View Post
I agree with you but, having been on the roads for more than 20 years, i've learned not to overestimate the intelligence of the average driver.
Nor the intelligence of the civil engineer. Especially the civil engineers in Las Vegas. 5 god damn minutes to make a left hand turn!
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Old 06-01-2010, 11:50 PM
MEBuckner MEBuckner is offline
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Some intersections have a light that is either a green arrow (meaning oncoming traffic is blocked, and left-turners have the right-of-way) or else that light shows nothing at all, even while the main traffic signal for that side of the street is green (meaning that if the general signal is green, left-turners can still turn if it is safe to do so, but must yield to oncoming traffic). The "turn on green arrow only" signs are to emphasize that this is NOT one of those intersections; those wishing to turn left must wait for an explicit green arrow.
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Old 06-01-2010, 11:56 PM
asian_riff asian_riff is offline
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Last edited by asian_riff; 06-01-2010 at 11:58 PM.. Reason: previous post explained it better than I did
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  #8  
Old 06-02-2010, 12:07 AM
suranyi suranyi is offline
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Originally Posted by SenorBeef View Post
I guess that's a logical interpretation, but it seems unnecesary. If the light for your lane is red, you don't go anywhere, that's obvious. You might as well put a sign on top of every normal stoplight that says "do not go through intersection on red" just in case people forget.
In Montreal there actually are signs at many intersections that say (translated from French) "wait for the green light".
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Old 06-02-2010, 04:12 AM
Richard Pearse Richard Pearse is offline
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What is the purpose of "turn on green arrow only" signs?

In my experience signs like that are placed in response to drivers not doing the right thing. Sometimes it might be at a particular intersection or if it's a common problem the sign will be at all suitable intersections.
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Old 06-02-2010, 06:13 AM
Colophon Colophon is offline
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There are lots of traffic lights, at least around here, that don't have totally separate lights for each lane. Instead there'll be the usual red, amber and green, with a separate green arrow bolted onto the side, which normally isn't lit at all. In these cases, a "turn only on green arrow" sign would be useful. There never seem to be any, though.

This is the kind of thing I mean. Imagine just the bottom green light is on (but not the arrow). Some people might think that gave them the go-ahead to turn left as well as proceed straight ahead, as there is no "red arrow".

Last edited by Colophon; 06-02-2010 at 06:14 AM..
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  #11  
Old 06-02-2010, 08:44 AM
TriPolar TriPolar is offline
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In some states a green light in the main traffic lane(s) indicates that you may also turn left or right, even if a red arrow is showing for a left or right turn. The sign is there to modify that general rule, allowing turns only when there is a green arrow. Sometimes a light has been re-timed so that there is never a red arrow and green light together, and the sign was just left there, perhaps in anticipation of a future change.
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Old 06-02-2010, 08:45 AM
Markxxx Markxxx is offline
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On Kedzie and Fullerton in Chicago, there is a "Turn left on green arrow only" sign.

It's used because then you'd have people sitting in the lane on the green light waiting to turn left, and they would clog the road. This way the green light means you can go straight or turn right. Then the light turns red and the green left arrow comes on, and those cars get a turn, then it goes to right and the other street goes
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Old 06-02-2010, 09:13 AM
Sailboat Sailboat is offline
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Originally Posted by SenorBeef View Post
I guess that's a logical interpretation, but it seems unnecesary. If the light for your lane is red, you don't go anywhere, that's obvious. You might as well put a sign on top of every normal stoplight that says "do not go through intersection on red" just in case people forget.
You think that's bad...how about "yield to pedestrians in crosswalks" signs? Drivers are supposed to yield to pedestrians everywhere, all the time. This sign doesn't so much remind me to yield to them here, too, as it does cause me to speculate if it would be okay with the authorities if I run over anyone who strays outside the crosswalk lines.
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Old 06-02-2010, 09:31 AM
redtail23 redtail23 is offline
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Don't any of y'all have "left when clear" rules?

If there's a "left on arrow only" sign, then you must wait for the green arrow to turn left. The green arrow means that you have clear passage and right-of-way.

If there's no "arrow only" sign, you can still turn left when it's clear to do so. However, it's your job to determine that it's safe to turn and you must yield to all other traffic.

At least that's how I learned it, back when dinosaurs ruled.
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Old 06-02-2010, 10:29 AM
pulykamell pulykamell is online now
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Originally Posted by Markxxx View Post
On Kedzie and Fullerton in Chicago, there is a "Turn left on green arrow only" sign.

It's used because then you'd have people sitting in the lane on the green light waiting to turn left, and they would clog the road. This way the green light means you can go straight or turn right. Then the light turns red and the green left arrow comes on, and those cars get a turn, then it goes to right and the other street goes
That's not the same type of light the OP is describing (at least as I understand the OP). The Fullerton and Kedzie light (if I'm thinking of the right one) governs both the turn and main lanes has states:

RED, YELLOW, GREEN, YELLOW ARROW, GREEN ARROW

Normally, a green at an intersection (as you say) would permit advancing in either the main traffic lanes or the turn lane. For that intersection, though, they only want left turns explicitly on the green arrow.

The OP's light, located in the exit lane, has three states: RED, YELLOW, and GREEN ARROW. There should be no confusion, as there is no plain green to be confused by.

My only guess is it's to make clear that, hey, there's another set of lights here you need to follow, so don't pay attention to the lights for the through traffic lanes. I'm pretty sure I've seen lights set up like this around the Loop area, perhaps on Michigan Ave., and the extra sign has kept me from turning when I otherwise might have.
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Old 06-02-2010, 10:46 AM
Polycarp Polycarp is offline
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Another vote for the "It's a reminder not to follow the traffic going straight in whether or not you proceed", noting that it's often possible that other vehicles may restrict your range of vision, e.g., a large truck ahead of you whose box kieeps you from seeing one light or the other, or positioning of the lights such that the drivers of the first cars in line can only see the lights by craning their heads forward and upward, meaning there is a tendency to rely on traffic in other lanes for guidance.

Although the thought did strike me that "Turn on Green Arrow only" signs may be a good way to keep you from getting Speedy.
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  #17  
Old 06-02-2010, 11:12 AM
TriPolar TriPolar is offline
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Originally Posted by pulykamell View Post
The OP's light, located in the exit lane, has three states: RED, YELLOW, and GREEN ARROW. There should be no confusion, as there is no plain green to be confused by.
Not much help unless you stop at the intersection and wait for the light to cycle through its states.
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  #18  
Old 06-02-2010, 01:17 PM
pulykamell pulykamell is online now
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Originally Posted by ed malin View Post
Not much help unless you stop at the intersection and wait for the light to cycle through its states.
I'm not following you.

Anyhow, I just passed an intersection in Chicago which I think has the OP's configuration, except with states as red arrow, yellow arrow, green arrow.

Unfortunately, the Google vehicle is all the way in the right lane, so let me describe what you have:

You have the main traffic signals ahead of you, with the green arrows pointing up. Where you have that island separating north and southbound lanes is another set of traffic signals governing the turn. That set of lights has three states: red arrow, yellow arrow, and green arrow. There is a sign there now (although it doesn't seem to be in the Google capture) that says "Left turn on green arrow only" in addition to the other sign prohibiting left turns during certain hours.
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Old 06-02-2010, 01:26 PM
KneadToKnow KneadToKnow is offline
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Around here, the DOT apparently feels it necessary to remind people making U-turns that they must yield to right-turning traffic on the cross-street. I mean, really? You have to remind people at the absolute bottom of the right-of-way chain that they're supposed to yield to other drivers?

Oh, and don't even get me started on the ridiculous blinking turn arrows we have now.

Last edited by KneadToKnow; 06-02-2010 at 01:27 PM..
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Old 06-02-2010, 01:27 PM
SenorBeef SenorBeef is online now
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No, your intersection is considerably weirder than what I'm describing. I didn't think to use google street view to demonstrate my point though, good idea.

This is the sort of thing I mean. Totally typical intersection, 3 lanes on the right going straight and one lane on the left that's a turn only lane. You can't see it from the angle on the picture, but that light on the left only has red/yellow/green arrow states, and you can see (but not read) the little sign next to it indicating to only go on green arrow.

This isn't a weird intersection where people might be confused - it's a totally run of the mill turning lane.
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Old 06-02-2010, 01:29 PM
pulykamell pulykamell is online now
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It seems to be the same idea as what I had in mind (the left turn lane has red/yellow/green arrows pointing left), only difference is yours has all the lights mounted on the same crossbar (plus the intersection I linked to has a more explicit green arrow pointing up for the through lanes instead of just a plain green light). I think it's there just to serve as a reminder.

Last edited by pulykamell; 06-02-2010 at 01:32 PM..
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  #22  
Old 06-02-2010, 01:49 PM
panamajack panamajack is offline
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Originally Posted by KneadToKnow View Post
Around here, the DOT apparently feels it necessary to remind people making U-turns that they must yield to right-turning traffic on the cross-street. I mean, really? You have to remind people at the absolute bottom of the right-of-way chain that they're supposed to yield to other drivers?

Oh, and don't even get me started on the ridiculous blinking turn arrows we have now.
Maybe they need to keep out-of-staters informed; in my state (CA), the U-turning vehicle would have the right-of-way if it's not controlled by a sign. I don't know if that's more or less common around the country, though.
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Old 06-02-2010, 02:01 PM
KneadToKnow KneadToKnow is offline
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Originally Posted by panamajack View Post
Maybe they need to keep out-of-staters informed; in my state (CA), the U-turning vehicle would have the right-of-way if it's not controlled by a sign. I don't know if that's more or less common around the country, though.
You may be right, then. I would never have thought a U-turn-ing vehicle would ever have the right-of-way.
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Old 06-02-2010, 02:36 PM
kunilou kunilou is online now
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Originally Posted by SenorBeef View Post
This is the sort of thing I mean. Totally typical intersection, 3 lanes on the right going straight and one lane on the left that's a turn only lane. You can't see it from the angle on the picture, but that light on the left only has red/yellow/green arrow states, and you can see (but not read) the little sign next to it indicating to only go on green arrow.
Makes perfect sense to me. I can see three possible reasons:

a) Like Markxxx said, there's enough oncoming traffic that the people turning left would never get out. While your green arrow is on, the oncoming traffic has a red light. The oncoming traffic turning left may also get a green arrow at the same time.

b) For some reason, the lights for through and oncoming lanes are timed differently (as part of the master traffic signal grid), and just because the through lanes have a green light, the oncoming lanes may be timed differently.

c) The pedestrian traffic at the corner is so heavy that the WALK signal has priority over traffic. In other words, the car turning left on green has to wait until the pedestrians have the chance to cross the street. The green arrow doesn't come on until the pedestrians have a DON'T WALK signal.
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Old 06-02-2010, 02:59 PM
pulykamell pulykamell is online now
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I think the question is why is there this redundancy? That is, why the sign saying "turn on green arrow only" when it should be obvious, given the presence of a red and yellow turn arrow? It's clear why one would have dedicated arrows for the turn lane, but why the dedicated arrows and the sign?

ETA: Put it this way, in effect, it's the same as having a normal controlled intersection, with a sign saying "Proceed on green only."

Last edited by pulykamell; 06-02-2010 at 03:01 PM..
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Old 06-02-2010, 03:17 PM
crowmanyclouds crowmanyclouds is offline
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Originally Posted by pulykamell View Post
I think the question is why is there this redundancy? ...
Because there are morans out there that don't get that the light for the turn lane and the light for the through lane are the lights for those lanes and those lanes only!

CMC fnord!
ETA to your ETA Ever notice those signs that say "Delayed Green"? That's cause there's a shitload of morans that think that when the cross traffic light turns red they can go ... even if their light is still red.
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Old 06-02-2010, 03:22 PM
pulykamell pulykamell is online now
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Originally Posted by crowmanyclouds View Post
Because there are morans out there that don't get that the light for the turn lane and the light for the through lane are the lights for those lanes and those lanes only!
Yes, I agree, and I stated as much upthread.

More usefully (in the sense they do alter behavior because of the sign), the signs exist for the situation Markxxx described, in which you have a single traffic light governing both turn and through lanes with five states: red, yellow, green, yellow arrow, green arrow. Normally, you can turn left on green or on the green arrow. "Turn left on green arrow only" eliminates the turn on green light option. This is not the situation the OP is describing, though.
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Old 06-02-2010, 03:29 PM
Maggie the Ocelot Maggie the Ocelot is offline
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  #29  
Old 06-02-2010, 03:29 PM
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Originally Posted by KneadToKnow View Post
You may be right, then. I would never have thought a U-turn-ing vehicle would ever have the right-of-way.
making a u turn on a green arrow is a protected turn, making a right turn on red is not. (may vary by state)

to the op is the street you are turning left onto a one way? most states have rules allowing left turns on red if you are turning onto a one way street, which means some times the need for a no turn on red sign.
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Old 06-02-2010, 03:47 PM
pulykamell pulykamell is online now
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Originally Posted by Critical1 View Post
most states have rules allowing left turns on red if you are turning onto a one way street, which means some times the need for a no turn on red sign.
Isn't the rule more commonly when you're making a left turn from a one-way street onto another one way street? I've never seen a left turn on red from a two-way street unto a one-way street permitted.
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Old 06-02-2010, 03:52 PM
SenorBeef SenorBeef is online now
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Originally Posted by Critical1 View Post
to the op is the street you are turning left onto a one way? most states have rules allowing left turns on red if you are turning onto a one way street, which means some times the need for a no turn on red sign.
Nope, it's a totally run of the mill intersection. I just picked that as an example - many (most? not all) of the places around vegas have those signs next to dedicated turn lanes, so it's not an abnormal situation that needs a special warning at all.
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Old 06-02-2010, 04:03 PM
Critical1 Critical1 is offline
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Originally Posted by pulykamell View Post
Isn't the rule more commonly when you're making a left turn from a one-way street onto another one way street? I've never seen a left turn on red from a two-way street unto a one-way street permitted.
in Washington you can turn left onto a one way from either,


idk about the signage from the op, sounds like its just a place where people for whatever reason keep turning on red so the added a sign.

reminds me of the occasional "left turn must yield on (green ball)" signs you see every now and then.
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Old 06-02-2010, 04:09 PM
pulykamell pulykamell is online now
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Originally Posted by Critical1 View Post
in Washington you can turn left onto a one way from either.
Interesting...and odd (to me, at any rate). In Illinois it's only permitted from one one-way to another, which makes sense to me, as it's basically acts like a right turn on red in that case (in other words, you're not crossing across any lanes of traffic.)

Ah, Wikipedia has info on this:

Quote:
In U.S., 37 states and Puerto Rico allow left turns on red only if both the origin and destination streets are one way [...]

Five other states, namely Alaska, Idaho, Michigan, Oregon and Washington, allow left turns on red even from a two-way street.
Well, good thing to know for next time I'm in Michigan. But it is in the minority as far as US traffic laws are concerned.

Last edited by pulykamell; 06-02-2010 at 04:10 PM..
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  #34  
Old 06-02-2010, 07:06 PM
pudytat72 pudytat72 is offline
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"Turn on green arrow only" may also be used when the person in the left turn lane does not have good enough visibility to judge oncoming traffic (can't see if it is truly safe to turn)

Some of the left turn's in my city now have a green arrow (for protected turns) and a flashing yellow arrow (means you can turn if it is safe-but the oncoming traffic has a green light). They said that a some people seeing a solid green left turn light felt that they had a protected turn and were pulling into oncoming traffic and getting hit. The flashing yellow arrow indicates that you can turn, but use caution.

Some intersections with high left turn volume now have protected "green arrow" turns at the beginning and at the end of the green light cycle. That has really help cut down on having to sit through multiple light cycles.

Last edited by pudytat72; 06-02-2010 at 07:07 PM..
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  #35  
Old 06-02-2010, 07:07 PM
elfkin477 elfkin477 is offline
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Originally Posted by mhendo View Post
I agree with you but, having been on the roads for more than 20 years, i've learned not to overestimate the intelligence of the average driver.
No kidding. Despite a "no left hand turn on red arrow" sign, I was behind someone today who apparently got bored of waiting and did just that. It was very strange, since he'd been waiting, so it wasn't like he'd barely missed the light change.
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  #36  
Old 06-02-2010, 11:58 PM
panamajack panamajack is offline
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This is just a guess, but something I observed today.

A very common mistake made at stoplights with separate green lights for the left turn, even when they're arrows, is to go as soon as any light turns green. I suppose it's possible that the sign might subtly reinforce to someone waiting for the straight light, who read it with nothing else to look at, that they shouldn't go if they aren't turning when they see a green arrow.

No idea if that would help, but it may be a reason for the redundant sign.

(And to nitpick myself : The CA rules of the road regarding U-turns & right turns don't cede right-of-way to all U-turners over right-turners, but in some, including the most common, situations.)
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Old 06-03-2010, 12:24 AM
NoiseBomb NoiseBomb is offline
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Oh, and don't even get me started on the ridiculous blinking turn arrows we have now.
I did a double-take the first time I saw one of those. A flashing yellow arrow... HUH? No spots on my glasses, my brain is properly caffeinated, is the signal broken or something?

OK, I get that it seems to mean "You may turn left (on to I-85 from a turn-only lane) if it's clear but be aware oncoming traffic has a green light" but I'd never seen or heard of such a thing before.

Last edited by NoiseBomb; 06-03-2010 at 12:24 AM..
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  #38  
Old 06-08-2010, 01:33 PM
Irishman Irishman is offline
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SenorBeef said:
Quote:
But the thing is - the only states that leftmost light has is red, yellow, and a green arrow. They never ever just have a plain green light. There is never a situation in which you would alter your behavior because of that sign.

So why are they there?
Other situations make more sense. In the situation you describe, I can only assume it is for idiot drivers. "Wait, I don't go just because the straight lanes go?"

KneadToKnow said:
Quote:
Around here, the DOT apparently feels it necessary to remind people making U-turns that they must yield to right-turning traffic on the cross-street. I mean, really? You have to remind people at the absolute bottom of the right-of-way chain that they're supposed to yield to other drivers?
Now I need to go look that up. Consider a left turn lane, needing to U-turn. Left only light triggers, roll up and as I start around the bend, the cross traffic right lane guy is right turning. Even after I've started the U and am clearly aiming for that lane. See, it's a protected Left, so I am in the lane with a green light, where as the right turner is in a lane with a red light. Clearly I have right of way.

Okay, like I said, I should look that up.

Critical1 said:
Quote:
most states have rules allowing left turns on red if you are turning onto a one way street, which means some times the need for a no turn on red sign.
You can turn left on red from a 2 way street? Seems risky - you are crossing a traffic lane - your oncoming traffic.

pudytat72 said:
Quote:
Some of the left turn's in my city now have a green arrow (for protected turns) and a flashing yellow arrow (means you can turn if it is safe-but the oncoming traffic has a green light). They said that a some people seeing a solid green left turn light felt that they had a protected turn and were pulling into oncoming traffic and getting hit. The flashing yellow arrow indicates that you can turn, but use caution.
Just shows there's no universal standard. Never seen a flashing yellow arrow. We would indicate that with an green arrow for protected left and a green ball for left but oncoming traffic has green. I suppose the counter argument is that a green ball would suggest traffic can also go straight from that lane. Even from a dedicated left lane with a median in front of it?

elfkin477 said:
Quote:
No kidding. Despite a "no left hand turn on red arrow" sign, I was behind someone today who apparently got bored of waiting and did just that. It was very strange, since he'd been waiting, so it wasn't like he'd barely missed the light change.
Some lights have preposterous timing. I came from a place where it was pretty much standard for left turns to either be simultaneous with straight traffic, or preceed it. Never followed straight traffic. Moved to Houston and discovered lights in any sequence. First time I encountered left turn last it confused me. So say you enter the left turn lane just late enough that the trigger doesn't put you in that light cycle, and the light goes to red, no turn. You sit patiently through the cross traffic, then it's "your turn" and the light skips you and goes to straight traffic. WTF? Oh, it's a red last light.

Some lights have a 2 minute wait. 2 minutes sitting for the full light cycle before you get the go. That is fine if traffic really is that heavy, but typically there is a lull somewhere where oncoming traffic is open but you have a red light, no turn. That is frustrating. Sitting and sitting and sitting where you have good visibility, no oncoming traffic, and you are still red.
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  #39  
Old 06-08-2010, 02:14 PM
JerseyFrank JerseyFrank is offline
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I've seen many light patterns. Here in NJ (and I'll presume elsewhere), there are "delayed green" patterns. You'll be sitting in the left turn lane at a red light. The light is red for all traffic in your direction. Traffic on the perpendicular road gets a red light, then the opposing side gets its green light. They then get the red, and you'll get the green.

No arrows. No indication that it is safe to turn, except that you see cars have stopped from the opposite direction. You have to understand that "delayed green" and "wait for green" mean that you will get a green signal after opposing traffic has completed its cycle. If you are on the other side, the sign will say "opposing traffic has delayed green" (or something akin to that).

With the sea of jughandles, circles, turn arrows, cycled no-turn-on-red lighted signs... well, I'll take all the reminders I can get.

ETA: In direct response to the OP, the signs are there as a reminder that this signal differs from the variety of other signals found on this road. There's a road very near my home that has several different left-turn methods and rules. Jughandles, 3 separate arrow colors, 3 arrow colors in one lamp, delayed greens with left turns, delayed greens with jughandles... every single intersection seems to present something new, and all within a span of 5 miles or so.

Last edited by JerseyFrank; 06-08-2010 at 02:18 PM..
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  #40  
Old 06-08-2010, 02:17 PM
KneadToKnow KneadToKnow is offline
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Quote:
Originally Posted by Irishman
Quote:
Originally Posted by KneadToKnow
Around here, the DOT apparently feels it necessary to remind people making U-turns that they must yield to right-turning traffic on the cross-street. I mean, really? You have to remind people at the absolute bottom of the right-of-way chain that they're supposed to yield to other drivers?
Now I need to go look that up. Consider a left turn lane, needing to U-turn. Left only light triggers, roll up and as I start around the bend, the cross traffic right lane guy is right turning. Even after I've started the U and am clearly aiming for that lane. See, it's a protected Left, so I am in the lane with a green light, where as the right turner is in a lane with a red light. Clearly I have right of way.
I drove through the intersection that was on my mind when I posted that just the other day, and I'd like to add that it does not have a left-turn lane and likewise does not have a left-turn arrow, so persons making a U-turn there are not, as I understand the term, making a protected turn.
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Old 06-08-2010, 03:39 PM
groman groman is offline
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Originally Posted by Irishman View Post
You can turn left on red from a 2 way street? Seems risky - you are crossing a traffic lane - your oncoming traffic.
Your oncoming traffic is hopefully stopped at that same red light, isn't it?
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Old 06-08-2010, 03:51 PM
Baracus Baracus is offline
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Originally Posted by Irishman View Post
Now I need to go look that up. Consider a left turn lane, needing to U-turn. Left only light triggers, roll up and as I start around the bend, the cross traffic right lane guy is right turning. Even after I've started the U and am clearly aiming for that lane. See, it's a protected Left, so I am in the lane with a green light, where as the right turner is in a lane with a red light. Clearly I have right of way.
Unless the right turner has a green arrow for his right turn, which is usually the case where I see the "U-turn must yield" signs.
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  #43  
Old 06-08-2010, 05:21 PM
Irishman Irishman is offline
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KneadToKnow said:
Quote:
I drove through the intersection that was on my mind when I posted that just the other day,
Fair enough, but your comment about bottom of the right of way chain was presented as an absolute, not a specific intersection case.

And really, I still don't see why U turn is bottom of right of way. He's the one flowing with traffic, with the light, even if it is an unprotected left. The right turner is at a "stop until clear" signal.


groman said:
Quote:
Your oncoming traffic is hopefully stopped at that same red light, isn't it?
You are assuming that crossflow traffic is syncronous. JerseyFrank just described the case where flow alternates by direction, so there are four points in the traffic cycle, not 2. My direction goes. Then opposite oncoming goes. Then traffic from my right goes. Then traffic from my left. If the standard default is that you can left on red from a 2 way street, then that case would require additional signage. Of course, in a state with that law, they may take that into consideration and avoid light combinations that create the risk. Traffic engineers may be crazy, but they are probably not that incompetent.

Last edited by Irishman; 06-08-2010 at 05:24 PM..
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  #44  
Old 10-20-2012, 09:31 PM
Mdcastle Mdcastle is online now
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Dragging this up because I noticed this in Chicago yesterday I have an answer for the question. The sign is the city of Chicago being cheap-ass. The intent is to have a protected only turns, but they're too cheap to put up a proper display of green arrow, yellow arrow, red arrow so they just use the cheaper setup intended for protected / permissive and turn it into protected only by banning the permsisive part with a sign. This practice is absolutely not allowd by the MUTCD, but Chicago just does it anyway.
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