Traffic signal

[interstatefan990]

While we're on the topic of bike signals, does anyone know how long a bicycle yellow is?

[kphoger]

While we're on the topic of bike signals, does anyone know how long a bicycle yellow is?

12 inches

[mrsman]

https://goo.gl/maps/89qY1MBmGiyhag6N8
This one in NJ gets me wondering.  Why is not the overhead heads also double red as well as the two side mounts?

In addition prior to the signal there is an overhead flashing warning of the signal indicating that this is a problem intersection with red light jumpers.  However, being three signals are immediately behind this one intersection, I find that one hard to believe that someone would miss this particular signal yet they do.

What are the double red signals even used for? I have never seen one before.

Double red signals are usually reserved for intersections where a municipality has somewhat regular issues with signal compliance (typically, lots of red light running). I only knew of two signals in Washington with double reds, but they've been removed.

As to the signals in New Jersey: my guess is that the double red signals were used at the stop line to more clearly indicate to approaching traffic exactly where the stop line is. With the curve, it might also be the case that the near side signals are the first ones visible. It's possible that the overhead near side mast arm was not strong enough to support a fourth signal head, so only the post-mounted signals received double reds.

It seems that they are used to emphasize the reds.  Kind of like the 12-8-8 signals that emphasize the reds over a regular 8-8-8 signal.  Now in a world where every signal is 12-12-12 and there does not seem to be an interest in signal heads larger than 12 inches a double red is needed to provide the emphasis.

It really should only be used in intersections with red light running problems.  We shouldn't see this all over the place.

[kphoger]

In my Illinois example, I believe it's due to the curvy road.  I'm not aware of a red-light running problem, just a sight line problem.  There are also advance warning signs.

[interstatefan990]

In my Illinois example, I believe it's due to the curvy road.  I'm not aware of a red-light running problem, just a sight line problem.  There are also advance warning signs.

In most places with reduced sight lines, there's a Signal Ahead symbol sign and that's usually enough. I wonder what situations specifically necessitate a sign and a double red signal. Plus, I've seen curves with much worse sight lines that only had a sign (or even nothing at all).

[UnumProvident101]

at this intersection in Chattanooga to the right there is a walking bridge but only bikes can turn right except for cars
https://www.google.com/maps/@35.0623788,-85.3068058,2a,75y,88.4h,87.06t/data=!3m6!1e1!3m4!1sHOcFl19O9lLLkHy9sGYJmQ!2e0!7i16384!8i8192

[jakeroot]

In my Illinois example, I believe it's due to the curvy road.  I'm not aware of a red-light running problem, just a sight line problem.  There are also advance warning signs.

In most places with reduced sight lines, there's a Signal Ahead symbol sign and that's usually enough. I wonder what situations specifically necessitate a sign and a double red signal. Plus, I've seen curves with much worse sight lines that only had a sign (or even nothing at all).

Typically with reduced sightlines, you also want supplemental signals, either on the near-side or far-side, typically in the corners of intersections or overhead on the mast arm, facing away from the intersection.

[jeffandnicole]

https://goo.gl/maps/89qY1MBmGiyhag6N8
This one in NJ gets me wondering.  Why is not the overhead heads also double red as well as the two side mounts?

In addition prior to the signal there is an overhead flashing warning of the signal indicating that this is a problem intersection with red light jumpers.  However, being three signals are immediately behind this one intersection, I find that one hard to believe that someone would miss this particular signal yet they do.

What are the double red signals even used for? I have never seen one before.

Double red signals are usually reserved for intersections where a municipality has somewhat regular issues with signal compliance (typically, lots of red light running). I only knew of two signals in Washington with double reds, but they've been removed.

As to the signals in New Jersey: my guess is that the double red signals were used at the stop line to more clearly indicate to approaching traffic exactly where the stop line is. With the curve, it might also be the case that the near side signals are the first ones visible. It's possible that the overhead near side mast arm was not strong enough to support a fourth signal head, so only the post-mounted signals received double reds.

With signals like this, I just chalk it up to an intern trying to impress the bosses with the unique (for NJ) double reds. 

The prior signal, seen in the older GSVs, it pretty standard for a NJ signal.  2 signals over 3 lanes on the far side; 1 signal on the near side over the opposing lanes. 

With the signal additions, there's now 8 red lights on 6 signal assemblies.  There's an overhead 'Signal Ahead' sign with yellow blinkers, and 2 'Signal Ahead' signs on the shoulder.  And there was a light post and mast added in the median, when the state is generally moving them away.  Even in this state that often has a lot of signal placements at each intersection, what you see here is very unusual.

It appears this may have been done at the same time the signal to the west was modified, which was done in a much more typical style for modern signals in NJ.

[interstatefan990]

In my Illinois example, I believe it's due to the curvy road.  I'm not aware of a red-light running problem, just a sight line problem.  There are also advance warning signs.

In most places with reduced sight lines, there's a Signal Ahead symbol sign and that's usually enough. I wonder what situations specifically necessitate a sign and a double red signal. Plus, I've seen curves with much worse sight lines that only had a sign (or even nothing at all).

Typically with reduced sightlines, you also want supplemental signals, either on the near-side or far-side, typically in the corners of intersections or overhead on the mast arm, facing away from the intersection.

Yes, but when do you need double red signals? They're right next to each other on the same signal head, there isn't much of a benefit unless you only have a few seconds to perceive and react to the current signal indication upon coming in view of it. And even then, the benefit is very small. I feel like the better option is to erect 1 or 2 advance signals, kind of like what some states do when the intersection is very large and the mast arm holding the main set is far from the stop line.

Here is an example on NY-22 of where I think a double red would make sense. The signal is situated in the middle of a sharp curve on a 55 MPH stretch of roadway. Even with the warning sign in place, a double red on each of the through signal heads would help give drivers more time to react and stop if necessary.

https://goo.gl/maps/CuwvGftiEvKRg9bn8

[jakeroot]

In my Illinois example, I believe it's due to the curvy road.  I'm not aware of a red-light running problem, just a sight line problem.  There are also advance warning signs.

In most places with reduced sight lines, there's a Signal Ahead symbol sign and that's usually enough. I wonder what situations specifically necessitate a sign and a double red signal. Plus, I've seen curves with much worse sight lines that only had a sign (or even nothing at all).

Typically with reduced sightlines, you also want supplemental signals, either on the near-side or far-side, typically in the corners of intersections or overhead on the mast arm, facing away from the intersection.

Yes, but when do you need double red signals? They're right next to each other on the same signal head, there isn't much of a benefit unless you only have a few seconds to perceive and react to the current signal indication upon coming in view of it. And even then, the benefit is very small. I feel like the better option is to erect 1 or 2 advance signals, kind of like what some states do when the intersection is very large and the mast arm holding the main set is far from the stop line.

I was more replying to your comment that "signal ahead symbol signs" are "usually enough", which I would say is only half true and that you also want some "custom" signalization (i.e., supplemental signals). But I can see from the rest of your reply that you're already in agreement with me in that regard, so I'll just leave it there.

[jakeroot]

This is perhaps a one-off in terms of signal placement:

3rd Ave SE @ 112th St SE, south of Everett, WA.

Two far-side post-mounted signals, and a single near-side overhead signal. Not sure I've seen anything like this before.

[SkyPesos]

When you reuse a left turn signal that's now a closed exit from a dead mall to a right turn signal for the opposite side...

[jakeroot]

When you reuse a left turn signal that's now a closed exit from a dead mall to a right turn signal for the opposite side...

It looks like it fell backwards? Just hanging on by a thread, almost literally.

As a side-note: Crestwood is a lot flatter than I remember ten years ago...

[interstatefan990]

In my Illinois example, I believe it's due to the curvy road.  I'm not aware of a red-light running problem, just a sight line problem.  There are also advance warning signs.

In most places with reduced sight lines, there's a Signal Ahead symbol sign and that's usually enough. I wonder what situations specifically necessitate a sign and a double red signal. Plus, I've seen curves with much worse sight lines that only had a sign (or even nothing at all).

Typically with reduced sightlines, you also want supplemental signals, either on the near-side or far-side, typically in the corners of intersections or overhead on the mast arm, facing away from the intersection.

Yes, but when do you need double red signals? They're right next to each other on the same signal head, there isn't much of a benefit unless you only have a few seconds to perceive and react to the current signal indication upon coming in view of it. And even then, the benefit is very small. I feel like the better option is to erect 1 or 2 advance signals, kind of like what some states do when the intersection is very large and the mast arm holding the main set is far from the stop line.

I was more replying to your comment that "signal ahead symbol signs" are "usually enough", which I would say is only half true and that you also want some "custom" signalization (i.e., supplemental signals). But I can see from the rest of your reply that you're already in agreement with me in that regard, so I'll just leave it there.

Got it, I was just trying to get an answer because I'm curious as to what the requirements are for a double red.

[jeffandnicole]

When you reuse a left turn signal that's now a closed exit from a dead mall to a right turn signal for the opposite side...

It takes 15 minutes max to open up each housing, turn the light to face the other direction, and reconnect the wiring for the red and green arrows (yellow wires would stay the same).

[plain]

I agree with jakeroot on that signal. Looks like the signal simply fell/got knocked off its pole and is upside-down facing the opposite direction. I tried playing around in the Street View to see what color it is when the rest of that direction was green but couldn't come up with anything.

[roadman65]

https://goo.gl/maps/2NYTYrCeTXQuTuzw7  Looks okay here. However profile those right turn signals have strange visors. https://goo.gl/maps/ve9i5PuJa9KNLLpw8

[SkyPesos]

When you reuse a left turn signal that's now a closed exit from a dead mall to a right turn signal for the opposite side...

It takes 15 minutes max to open up each housing, turn the light to face the other direction, and reconnect the wiring for the red and green arrows (yellow wires would stay the same).

Or the wires snapped and the signal fell off since the GSV was taken in 2019  . I need to check this signal out the next time I'm in St Louis to see if it's gone or replaced yet.

Though I find it interesting that this signal 'sat' on top of the pole, while the other 3 pole mounted ones in the intersection was mounted in front of it.

[jakeroot]

There are at least two indications that it fell backwards: the visors are upside down, and the wiring is entering through a hole in the top that would normally be on the bottom and covered by the pole:


Upside-down Signal by Jake Root, on Flickr

[Kasey]

Hello, I own several signals if anyone wants to see.

[fwydriver405]

If I recall correctly, flashing yellow arrow right turn signals either having a leading protected phase OR on recall transitioning from the protected phase to the permissive phase must have a steady yellow arrow phase before going to either a steady red or flashing yellow arrow, correct? After the steady yellow arrow transitioning into the permissive phase, does it matter if there is a red arrow for a few seconds, or can it go directly to flashing yellow arrow?

A steady right-turn YELLOW ARROW signal indication shall be displayed following the right-turn GREEN ARROW signal indication.

This FYA right turn signal in Portsmouth NH (43.0778743, -70.7618545) has no steady yellow arrow clearance (on pedestrian recall) between the protected phase and permissive phase. For the record, if the pedestrian button was pressed before Maplewood Ave traffic has their green, there is an LPI during the walk phase, followed by the FYA during the DON'T WALK phase.

[fwydriver405]

There are at least two indications that it fell backwards: the visors are upside down, and the wiring is entering through a hole in the top that would normally be on the bottom and covered by the pole:


Upside-down Signal by Jake Root, on Flickr

I have a strong feeling that the configuration of the opposing leg mirrors the configuration of the open leg, as the 4-section signal for the closed leg is still operating. EDIT: based on lane and signal configuration, operating in split phasing.

Aug 2018 Streetview

[mrsman]

If I recall correctly, flashing yellow arrow right turn signals either having a leading protected phase OR on recall transitioning from the protected phase to the permissive phase must have a steady yellow arrow phase before going to either a steady red or flashing yellow arrow, correct? After the steady yellow arrow transitioning into the permissive phase, does it matter if there is a red arrow for a few seconds, or can it go directly to flashing yellow arrow?

A steady right-turn YELLOW ARROW signal indication shall be displayed following the right-turn GREEN ARROW signal indication.

This FYA right turn signal in Portsmouth NH (43.0778743, -70.7618545) has no steady yellow arrow clearance (on pedestrian recall) between the protected phase and permissive phase. For the record, if the pedestrian button was pressed before Maplewood Ave traffic has their green, there is an LPI during the walk phase, followed by the FYA during the DON'T WALK phase.

I think you are right that this is a violation of MUTCD.

It is definitely a good practice to transition from a more open phase to a more restrictive phase with a yellow.  This seems like a requirement of the MUTCD.  So (i) green-yellow-red, (ii) green arrow-yellow arrow-red arrow, (iii) green arrow-yellow arrow-flashing yellow arrow, and (iv) flashing yellow arrow-yellow arrow-red arrow would all be required transitions. 

Going from more restrictive to less restrictive does not require a transition (in this country), so you have red-green, red arrow-green arrow, red arrow-flashing yellow arrow, and flashing yellow arrow-green arrow.  Of course, some foreign countries do have the combined red-yellow phase as a warning that a green is coming.  This is disallowed here to discourage people from stepping on the gas as soon as the light turns green - but there may be some value to it, especially in the era of people using cell phones at red lights.

There are some cases where you'd see green arrow-yellow arrow-brief red arrow-flashing yellow arrow.  The brief red arrow phase is not required, to my knowledge, but is sometimes helpful for safety purposes to force drivers to assess the situation between the protected turn and the permissive turn.  There was no way of incorporating a brief red arrow on doghouse signals, but it does exist on many of the 4 aspect FYA signals.  It is especially helpful in places with lots of peds or other complicated situations.

[SkyPesos]

There are at least two indications that it fell backwards: the visors are upside down, and the wiring is entering through a hole in the top that would normally be on the bottom and covered by the pole:


Upside-down Signal by Jake Root, on Flickr

I have a strong feeling that the configuration of the opposing leg mirrors the configuration of the open leg, as the 4-section signal for the closed leg is still operating.

Aug 2018 Streetview

It does, but because of the protected left signal on both sides, I doubt both sides turn green in the same phase. So the "upside down right turn signal"  would probably still be red when the other signals facing that side is green.

[fwydriver405]

There are at least two indications that it fell backwards: the visors are upside down, and the wiring is entering through a hole in the top that would normally be on the bottom and covered by the pole:

(img cut)

I have a strong feeling that the configuration of the opposing leg mirrors the configuration of the open leg, as the 4-section signal for the closed leg is still operating.

Aug 2018 Streetview

It does, but because of the protected left signal on both sides, I doubt both sides turn green in the same phase. So the "upside down right turn signal"  would probably still be red when the other signals facing that side is green.

You're right, my bad, I forgot to mention the phasing would be split phased. The latest GSV's have faded pavement, but past ones indicate the left lane is a shared left/thru, and the right lane a dedicated right turn lane. No way to have concurrent phasing with that lane and signal configuration.

EDIT: If you look closely, the latest GSV's show the 4-section signal on the active leg having left and right green arrows in the bottom 2 faces, in that order. July 2016 shows that the left arrow in the latest GSV's used to point straight. The non-active leg, however, also has right and left green arrows in the bottom 2 faces, in that order from as far back as 2009.