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Double-guy Mast Arm attachments.

Started by dbz77, July 06, 2019, 01:52:41 PM

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dbz77

Have any of you heard of the double guy mast arms used to hold up traffic signals? I have seen them before, just never knew what it was called until recently.

Here is a picture of two of them from the early 1960's.



Here are more recent pictures.


https://goo.gl/maps/qFWM9THrjCCTHDaH9

https://goo.gl/maps/3Xjmuw5zLy6NFL7M8

https://goo.gl/maps/8KX8R46HjG3wUdhY6

https://goo.gl/maps/WeeSk4owonhFehtJ7

https://goo.gl/maps/jbtEXvMU6sETLFc67

I wish I were in charge of new traffic signal installations. I would make sure all new traffic signal assemblies used the double-guy mast arm!


steviep24

That's an outdated design that no one installs anymore except for New York City. So if you want new signals installed this way NYC is the place for you.

jakeroot

#2
I am familiar with the double-guy mast arms, but they are pretty rare now.

The primary reason these types of signals are no longer used along major roads is due to changes in standards. Most states seem to require at least two overhead signals for an intersection with three approach lanes (perhaps one turn lane and two through lanes). Because these assemblies only support one overhead signal, they're primarily used only at one- or two-lane approaches these days, if at all. Most places use regular straight mast-arms now, with some places like CA and UT using a curved mast arm reminiscent of the double-guy mast arm days. Regular mast arms also help when using protected or protective/permissive left turn signals, which required median-placement before large mast arms were invented.

IIRC, the FHWA requires a minimum of one overhead signal for three through lanes, as long as sufficient pole-mounted supplementary signals are used. Most states use two overhead, but CA does occasionally use only one, with several pole-mounted supplementary signals (for the record, I quite like this linked setup, along with this similar example in Spokane, WA). In these instances, you could still use double-guy mast arms. But because of the popularity of the left-turn signal (whether protected or protective/permissive), mast arms that support at least two signal heads are now the norm.




Reposting this from the "extremely old signals" thread; relatively rare example in WA:

Quote from: jakeroot on July 06, 2019, 03:23:07 PM
Double-guy mast arms are very rare in WA, but Spokane has several that are left-over from days of yore. Image below of an example.

Unlike the other examples, the Spokane examples are all straight. Weirdly, the signals are "hung" from the top (note signal placement in the image below), but they don't swing around like the NYC signals. I've seen this style of signal placement along mast arms in some western states (chiefly CA, where they are especially common for left turn signals); never have fully understood why this was done.



roadfro

Quote from: dbz77 on July 06, 2019, 01:52:41 PM
I wish I were in charge of new traffic signal installations. I would make sure all new traffic signal assemblies used the double-guy mast arm!

They do look neat, but they are an outdated design that would only be practical to install in limited circumstances according to modern best practices of signal design.

Note for example that all of these only have one signal head on the arm, as I don't think many of these could support the weight of two or more signal heads. Modern best practice is to have at least two overhead signal heads on any road with more than two lanes (and one signal head per lane is recommended). So these would not be installed on major roads with three or more lanes nowadays, and wouldn't be considered by many states in situations with two lanes.
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

steviep24

#4
Quote from: jakeroot on July 06, 2019, 04:51:48 PM
I am familiar with the double-guy mast arms, but they are pretty rare now.

The primary reason these types of signals are no longer used along major roads is due to changes in standards. Most states seem to require at least two overhead signals for an intersection with three approach lanes (perhaps one turn lane and two through lanes). Because these assemblies only support one overhead signal, they're primarily used only at one- or two-lane approaches these days, if at all. Most places use regular straight mast-arms now, with some places like CA and UT using a curved mast arm reminiscent of the double-guy mast arm days. Regular mast arms also help when using protected or protective/permissive left turn signals, which required median-placement before large mast arms were invented.

IIRC, the FHWA requires a minimum of one overhead signal for three through lanes, as long as sufficient pole-mounted supplementary signals are used. Most states use two overhead, but CA does occasionally use only one, with several pole-mounted supplementary signals (for the record, I quite like this linked setup, along with this similar example in Spokane, WA). In these instances, you could still use double-guy mast arms. But because of the popularity of the left-turn signal (whether protected or protective/permissive), mast arms that support at least two signal heads are now the norm.




Reposting this from the "extremely old signals" thread; relatively rare example in WA:

Quote from: jakeroot on July 06, 2019, 03:23:07 PM
Double-guy mast arms are very rare in WA, but Spokane has several that are left-over from days of yore. Image below of an example.

Unlike the other examples, the Spokane examples are all straight. Weirdly, the signals are "hung" from the top (note signal placement in the image below), but they don't swing around like the NYC signals. I've seen this style of signal placement along mast arms in some western states (chiefly CA, where they are especially common for left turn signals); never have fully understood why this was done.


Rochester, NY used this style of double guyed mast arm at one time. Most were replaced with straight monotubes by the 70's. Some were used to support ultrasonic vehicle detectors. Those were mostly phased out by the 80's and 90's.

The last known double guyed (actually quadruple guyed) mast arm in the Rochester, NY area was this one at I 590 NB, Exit 2 (at NY 31). It was used in combination with a span wire install.

The interchange this was at was rebuilt a few years ago.

EDIT TO ADD: I found a few double guy mast arms in the Irondequoit area of NY 104 such as this one on Clinton Ave. These support ultra sonic vehicle detectors and it is unlikely that equipment is still in use.

dbz77

Quote from: steviep24 on July 06, 2019, 04:44:18 PM
That's an outdated design that no one installs anymore except for New York City. So if you want new signals installed this way NYC is the place for you.
Yeah, I checked out NYC on Google Maps.

Quote from: jakeroot on July 06, 2019, 04:51:48 PM
I am familiar with the double-guy mast arms, but they are pretty rare now.

The primary reason these types of signals are no longer used along major roads is due to changes in standards. Most states seem to require at least two overhead signals for an intersection with three approach lanes (perhaps one turn lane and two through lanes). Because these assemblies only support one overhead signal, they're primarily used only at one- or two-lane approaches these days, if at all. Most places use regular straight mast-arms now, with some places like CA and UT using a curved mast arm reminiscent of the double-guy mast arm days.
I suppose it is possible to design a double-guy curved mast arm or double-guy straight mast arm assembly that can hold two signals.

Quote from: jakeroot on July 06, 2019, 04:51:48 PMRegular mast arms also help when using protected or protective/permissive left turn signals, which required median-placement before large mast arms were invented.

IIRC, the FHWA requires a minimum of one overhead signal for three through lanes, as long as sufficient pole-mounted supplementary signals are used. Most states use two overhead, but CA does occasionally use only one, with several pole-mounted supplementary signals (for the record, I quite like this linked setup, along with this similar example in Spokane, WA). In these instances, you could still use double-guy mast arms. But because of the popularity of the left-turn signal (whether protected or protective/permissive), mast arms that support at least two signal heads are now the norm.
Mounting the left turn signal onto the mast arm has been done since at least the late 1970's, as can be seen from this video.



I do notice that pre-existing left-turn signals that were mounted on the median are being replaced with those mounted on the mast arm. Compare these two pictures.

https://goo.gl/maps/u6RMcVuEanqMTZ2y7


https://goo.gl/maps/hCyyuraNgLYx7z6q8

I wonder why this is being done. I suspect traffic signal assemblies have a service life of at least a century.

Quote from: jakeroot on July 06, 2019, 04:51:48 PM



Reposting this from the "extremely old signals" thread; relatively rare example in WA:

Quote from: jakeroot on July 06, 2019, 03:23:07 PM
Double-guy mast arms are very rare in WA, but Spokane has several that are left-over from days of yore. Image below of an example.

Unlike the other examples, the Spokane examples are all straight. Weirdly, the signals are "hung" from the top (note signal placement in the image below), but they don't swing around like the NYC signals. I've seen this style of signal placement along mast arms in some western states (chiefly CA, where they are especially common for left turn signals); never have fully understood why this was done.



The newest double-guy curved mast arm assemblies within one hundred miles where I live is along Hollywod Boulevard in Los Angeles, where the walk of fame is. The lamp posts were replaced a little over a decade ago, and with it, some new double-guy assembles were mounted on some of the lamp posts.

The newest double-guy assembly in Long Beach is at the corner of 5th and Cedar. It was installed in the early 2000's. (I recall in the late 1990's, there were no mast arm assembles there; only pole-mounted signals.

mrsman

As a native Californian, I always liked the old setup of signals.  Post mounted signals on the corners with 8-8-8 signals.  One overhead signal on streets that were wider than one lane in each direction with a 12-12-12 signal, hung by guy-wire.  To the extent possible, I felt it was cleaner when the signal hardware was hung up on streetlight posts, which existed in the majority of cases, but not every case.  To me it seemed sufficient for all but the widest streets (and in those cases they may string up an additional overhead from the left, like in the one-way streets in Downtown LA), and it provided a signal right where you were supposed to look as making a left turn [the far corner].

But as more traffic signals have arrows, the guy-wire mast arms can't handle the load, so they were replaced with curved mastarms that can handle heavier signal heads (like doghouses) and multiple signal heads for FYAs and protected only arrows.

Traffic signals in the median, while at one time common place at all singalized intersections with medians, are being removed almost everywhere in California except streets with really wide medians and in San Francisco.  The reason why they were removed was because too many of them were being struck down by cars.  The replacement, as shown in your Garden Grove example, is a wider mast arm (not guy wire) carrying an overhead signal and an overhead left signal.

I do recall some old setups with traffic signals that had a guy-wire from the left side.  So on the far-right corner, you'd have the typical pole mounted 8-8-8 and guy-wire 12-12-12.  On the far left corner yo'ud have a pole mounted 12-12-12 and a guy-wire 12-12-12 for the arrows.  While not using guy-wire, an example of this with a pole setup exists at 5th and Olive in Downtown LA.

https://www.google.com/maps/@34.049342,-118.2530366,3a,75y,31.67h,88.73t/data=!3m6!1e1!3m4!1sWPeLq3IBSiTxKozKD1nuzw!2e0!7i16384!8i8192


I don't have a good explanation as to what is going on on Hollywood Blvd.  The signals and the mastarms are old, even though they replaced the "Hollywood special" streetlight (3 bulbs and 5 red stars) with what they got now (retro look two tear drop lights per pole).  It's possible that they only replaced the tops of the streetlights and left the base (and the signal hardware) alone.  As said before, guy-wires are no longer being installed in L.A. (or most other places other than NYC).



dbz77

Quote from: mrsman on July 07, 2019, 01:39:07 PM
As a native Californian, I always liked the old setup of signals.  Post mounted signals on the corners with 8-8-8 signals.  One overhead signal on streets that were wider than one lane in each direction with a 12-12-12 signal, hung by guy-wire.  To the extent possible, I felt it was cleaner when the signal hardware was hung up on streetlight posts, which existed in the majority of cases, but not every case.  To me it seemed sufficient for all but the widest streets (and in those cases they may string up an additional overhead from the left, like in the one-way streets in Downtown LA), and it provided a signal right where you were supposed to look as making a left turn [the far corner].

But as more traffic signals have arrows, the guy-wire mast arms can't handle the load, so they were replaced with curved mastarms that can handle heavier signal heads (like doghouses) and multiple signal heads for FYAs and protected only arrows.
I must wonder why these new curved mast arms, which could handle heavier loads, do not have guy wires attached.
Quote from: mrsman on July 07, 2019, 01:39:07 PM
Traffic signals in the median, while at one time common place at all singalized intersections with medians, are being removed almost everywhere in California except streets with really wide medians and in San Francisco.  The reason why they were removed was because too many of them were being struck down by cars.  The replacement, as shown in your Garden Grove example, is a wider mast arm (not guy wire) carrying an overhead signal and an overhead left signal.
For some really wide streets, the main a=signal assembly is in the median.

roadfro

Quote from: dbz77 on July 07, 2019, 02:49:44 PM
Quote from: mrsman on July 07, 2019, 01:39:07 PM
As a native Californian, I always liked the old setup of signals.  Post mounted signals on the corners with 8-8-8 signals.  One overhead signal on streets that were wider than one lane in each direction with a 12-12-12 signal, hung by guy-wire.  To the extent possible, I felt it was cleaner when the signal hardware was hung up on streetlight posts, which existed in the majority of cases, but not every case.  To me it seemed sufficient for all but the widest streets (and in those cases they may string up an additional overhead from the left, like in the one-way streets in Downtown LA), and it provided a signal right where you were supposed to look as making a left turn [the far corner].

But as more traffic signals have arrows, the guy-wire mast arms can't handle the load, so they were replaced with curved mastarms that can handle heavier signal heads (like doghouses) and multiple signal heads for FYAs and protected only arrows.

I must wonder why these new curved mast arms, which could handle heavier loads, do not have guy wires attached.

The newer curved mast arms are designed similar to typical straight mast arms, so are engineered and built to withstand the load factor of signal heads, wind, etc. on their own without additional structural support. Part of this, I assume, is that the design employs much thicker masts and mast arms, which likely provides additional stability.
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

roadman65

#9
Quote from: steviep24 on July 06, 2019, 04:44:18 PM
That's an outdated design that no one installs anymore except for New York City. So if you want new signals installed this way NYC is the place for you.
New York City is the only place to also use old style analogue signal equipment that are still mounted to the signal poles.  In addition the city does not use the detector loops to control the timing and uses a default timer as well.

If you want to see (and hear) old signal equipment go to NYC.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

plain

Quote from: roadman65 on July 08, 2019, 11:05:07 AM
Quote from: steviep24 on July 06, 2019, 04:44:18 PM
That's an outdated design that no one installs anymore except for New York City. So if you want new signals installed this way NYC is the place for you.
New York City is the only place to also use old style analogue signal equipment that are still mounted to the signal poles.  In addition the city does not use the detector loops to control the timing and uses a default timer as well.

If you want to see (and hear) old signal equipment go to NYC.

Richmond also uses these, what I like to call "click boxes".
Newark born, Richmond bred

RestrictOnTheHanger

NYC can and does quite frequently mount 2 signals on a single guy wire setup.

Example 12 inch setup

Queens Blvd

https://maps.app.goo.gl/w7MYgSvAULKRKGNS8

dbz77

Quote from: RestrictOnTheHanger on July 08, 2019, 11:17:48 PM
NYC can and does quite frequently mount 2 signals on a single guy wire setup.

Example 12 inch setup

Queens Blvd

https://maps.app.goo.gl/w7MYgSvAULKRKGNS8
That would be impressive.

If only I were in charge of signal installations for Cal
Trans...

Roadwarriors79

You'll see some in Arizona. Most of the older signals like that are in the city of Phoenix. They are rarer, but scattered around in other places.

dbz77

Quote from: Roadwarriors79 on July 11, 2019, 01:32:41 PM
You'll see some in Arizona. Most of the older signals like that are in the city of Phoenix. They are rarer, but scattered around in other places.
I checked it out.

https://goo.gl/maps/V7YADAkJ7sFpJsQw8

https://goo.gl/maps/V7YADAkJ7sFpJsQw8

This is so awesome! CalTrans can learn a thing or two.

Roadwarriors79

Quote from: dbz77 on July 11, 2019, 11:04:36 PM
Quote from: Roadwarriors79 on July 11, 2019, 01:32:41 PM
You'll see some in Arizona. Most of the older signals like that are in the city of Phoenix. They are rarer, but scattered around in other places.
I checked it out.

https://goo.gl/maps/V7YADAkJ7sFpJsQw8

https://goo.gl/maps/V7YADAkJ7sFpJsQw8

This is so awesome! CalTrans can learn a thing or two.

The city of Phoenix was slow to replace the type of signals you like until about 10 years ago, when the light rail line first got built in the valley. Since then, Phoenix has installed newer signals than can span over wider intersections. Most newer installations look like this:

https://www.google.com/maps/@33.4068092,-112.1339672,3a,75y,124.49h,83.13t/data=!3m6!1e1!3m4!1s7RECntvg9K6iHiK1XribIg!2e0!7i16384!8i8192

Some installations are more of the "ADOT" style and they look like this:

https://www.google.com/maps/@33.4656898,-111.9870084,3a,75y,318.11h,72.23t/data=!3m7!1e1!3m5!1s2nfV8RNAFW-PDfBRGixNzg!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3D2nfV8RNAFW-PDfBRGixNzg%26output%3Dthumbnail%26cb_client%3Dsearch.TACTILE.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D212.38643%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

mrsman

Quote from: Roadwarriors79 on July 12, 2019, 08:57:50 PM
Quote from: dbz77 on July 11, 2019, 11:04:36 PM
Quote from: Roadwarriors79 on July 11, 2019, 01:32:41 PM
You'll see some in Arizona. Most of the older signals like that are in the city of Phoenix. They are rarer, but scattered around in other places.
I checked it out.

https://goo.gl/maps/V7YADAkJ7sFpJsQw8

https://goo.gl/maps/V7YADAkJ7sFpJsQw8

This is so awesome! CalTrans can learn a thing or two.

The city of Phoenix was slow to replace the type of signals you like until about 10 years ago, when the light rail line first got built in the valley. Since then, Phoenix has installed newer signals than can span over wider intersections. Most newer installations look like this:

https://www.google.com/maps/@33.4068092,-112.1339672,3a,75y,124.49h,83.13t/data=!3m6!1e1!3m4!1s7RECntvg9K6iHiK1XribIg!2e0!7i16384!8i8192

Some installations are more of the "ADOT" style and they look like this:

https://www.google.com/maps/@33.4656898,-111.9870084,3a,75y,318.11h,72.23t/data=!3m7!1e1!3m5!1s2nfV8RNAFW-PDfBRGixNzg!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3D2nfV8RNAFW-PDfBRGixNzg%26output%3Dthumbnail%26cb_client%3Dsearch.TACTILE.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D212.38643%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

McDowell/44th:  The new signals definitely look very sturdy and professional, but to me I just think there are more signal heads than necessary.  For a dual left turn lane, there are two left singal heads on the mast and one of the streetlight on the left corner.  And for 3 thru lanes, there are three overhead signal heads on the mast and one on the streetlight.  To me this is overkill.

As I mentioned earlier, I like the old California style.  I would have one left turn signal on the mast and one on the streetlight.  One thru signal on the streetlight, and at most two thru signals on the mast.

[The old CA style would have only one thru signal on the mast, but I can admit that this is a wide street so two signal heads may be appropriate, but not 3.]

If I had to generalize rules for appropriate signal head placement, I would say:

Two signal faces for every unique signalized movement, period.  Regardless of the movement.

If there are no special signals for turns, there should be a signal face at left corner, and one at the right corner.  If there are X thru lanes, there should also be X-1 signals on the mast.  [0 mast signals for one thru lane, 1 mast signal for 2 thru lanes, 2 mast signals for 3 thru lanes etc.]  Exception: 1 thru lane and 1 left turn lane will also include 1 signal on the mast.

If there are also signals for right turn movements that also contain the thru movement (doghouse, 5 aspect straight line), the signal face at the right corner should also have the right turn signal aspect.  There should also be a near side signal face that is equivalent.

If there are also signals for right turn movements that are unique (FYA or RA-YA-GA), one should be on the near side corner and one should be on the far side right corner.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  [These signals are relatively rare, and usually only used when there are heavy pedestrian movements.]

If there are also signals for left turn movements that also contain the thru movement (doghouse, 4 aspect straight line, 5 aspect straight line), the signal face at the far left corner should also have the left turn signal aspect.  The left most signal on the mast should also have a left turn signal aspect. 

If there are also signals for left turn movements that are unique (FYA or RA-YA-GA), one should be on the far left corner and one should be on the mast.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  (If there are theree or more left turn lanes, an additional left turn signal on the mast is appropriate).

jakeroot

#17
Quote from: mrsman on July 14, 2019, 10:08:51 AM
McDowell/44th:  The new signals definitely look very sturdy and professional, but to me I just think there are more signal heads than necessary.  For a dual left turn lane, there are two left singal heads on the mast and one of the streetlight on the left corner.  And for 3 thru lanes, there are three overhead signal heads on the mast and one on the streetlight.  To me this is overkill.

As I mentioned earlier, I like the old California style.  I would have one left turn signal on the mast and one on the streetlight.  One thru signal on the streetlight, and at most two thru signals on the mast.

[The old CA style would have only one thru signal on the mast, but I can admit that this is a wide street so two signal heads may be appropriate, but not 3.]

If I had to generalize rules for appropriate signal head placement, I would say:

Two signal faces for every unique signalized movement, period.  Regardless of the movement.

If there are no special signals for turns, there should be a signal face at left corner, and one at the right corner.  If there are X thru lanes, there should also be X-1 signals on the mast.  [0 mast signals for one thru lane, 1 mast signal for 2 thru lanes, 2 mast signals for 3 thru lanes etc.]  Exception: 1 thru lane and 1 left turn lane will also include 1 signal on the mast.

If there are also signals for right turn movements that also contain the thru movement (doghouse, 5 aspect straight line), the signal face at the right corner should also have the right turn signal aspect.  There should also be a near side signal face that is equivalent.

If there are also signals for right turn movements that are unique (FYA or RA-YA-GA), one should be on the near side corner and one should be on the far side right corner.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  [These signals are relatively rare, and usually only used when there are heavy pedestrian movements.]

If there are also signals for left turn movements that also contain the thru movement (doghouse, 4 aspect straight line, 5 aspect straight line), the signal face at the far left corner should also have the left turn signal aspect.  The left most signal on the mast should also have a left turn signal aspect. 

If there are also signals for left turn movements that are unique (FYA or RA-YA-GA), one should be on the far left corner and one should be on the mast.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  (If there are theree or more left turn lanes, an additional left turn signal on the mast is appropriate).

For your third-to-last suggestion (unique right turn signal), I agree with your suggestions, except that a second pole-mounted signal could be used on the far-side of the intersection. They could be placed right next to each other, perhaps appearing as one giant 6- (or 7-) face signal.

I think we would get along very nicely! I agree with all of your suggestions. CA has managed to figure out a remarkable feat: signalizing massive intersections (20-30 approach lanes) without having them appear too cluttered. Good signal spacing, backplates (so the signals don't get lost), two signals for every movement, overhead signals using through-minus-one as a base (though there are plenty with only one overhead for three approach lanes; hell, I've seen one overhead for four through lanes!), and so on. Very impressive attention to detail.

I don't know of any state that signalizes their intersections like California. CO is probably the closest, in that they often drop a second left turn signal overhead, in favor of having a second on the left-pole. Every other (AZ, NV, MN, IL) seems to have adopted signal-per-lane strategies; nothing wrong with this per-se, but I don't know how necessary it is to have what can only be described as, perhaps, overkill, at some intersections in places like Nevada (though to be clear, this is still way better than MUTCD-standard placement, which is god-awful).

Off-topic: you may like this intersection in Spokane, WA. It has four examples of double-left turns that swap having two overhead left turn signals, for one overhead and one on the left. The supplemental signals also don't use backplates, which I personally prefer (reducing clutter). Plus, they use through-minus-one for signal placement.

mrsman

#18
Quote from: jakeroot on July 14, 2019, 04:53:07 PM
Quote from: mrsman on July 14, 2019, 10:08:51 AM
McDowell/44th:  The new signals definitely look very sturdy and professional, but to me I just think there are more signal heads than necessary.  For a dual left turn lane, there are two left singal heads on the mast and one of the streetlight on the left corner.  And for 3 thru lanes, there are three overhead signal heads on the mast and one on the streetlight.  To me this is overkill.

As I mentioned earlier, I like the old California style.  I would have one left turn signal on the mast and one on the streetlight.  One thru signal on the streetlight, and at most two thru signals on the mast.

[The old CA style would have only one thru signal on the mast, but I can admit that this is a wide street so two signal heads may be appropriate, but not 3.]

If I had to generalize rules for appropriate signal head placement, I would say:

Two signal faces for every unique signalized movement, period.  Regardless of the movement.

If there are no special signals for turns, there should be a signal face at left corner, and one at the right corner.  If there are X thru lanes, there should also be X-1 signals on the mast.  [0 mast signals for one thru lane, 1 mast signal for 2 thru lanes, 2 mast signals for 3 thru lanes etc.]  Exception: 1 thru lane and 1 left turn lane will also include 1 signal on the mast.

If there are also signals for right turn movements that also contain the thru movement (doghouse, 5 aspect straight line), the signal face at the right corner should also have the right turn signal aspect.  There should also be a near side signal face that is equivalent.

If there are also signals for right turn movements that are unique (FYA or RA-YA-GA), one should be on the near side corner and one should be on the far side right corner.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  [These signals are relatively rare, and usually only used when there are heavy pedestrian movements.]

If there are also signals for left turn movements that also contain the thru movement (doghouse, 4 aspect straight line, 5 aspect straight line), the signal face at the far left corner should also have the left turn signal aspect.  The left most signal on the mast should also have a left turn signal aspect. 

If there are also signals for left turn movements that are unique (FYA or RA-YA-GA), one should be on the far left corner and one should be on the mast.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  (If there are theree or more left turn lanes, an additional left turn signal on the mast is appropriate).

For your third-to-last suggestion (unique right turn signal), I agree with your suggestions, except that a second pole-mounted signal could be used on the far-side of the intersection. They could be placed right next to each other, perhaps appearing as one giant 6- (or 7-) face signal.

I think we would get along very nicely! I agree with all of your suggestions. CA has managed to figure out a remarkable feat: signalizing massive intersections (20-30 approach lanes) without having them appear too cluttered. Good signal spacing, backplates (so the signals don't get lost), two signals for every movement, overhead signals using through-minus-one as a base (though there are plenty with only one overhead for three approach lanes; hell, I've seen one overhead for four through lanes!), and so on. Very impressive attention to detail.

I don't know of any state that signalizes their intersections like California. CO is probably the closest, in that they often drop a second left turn signal overhead, in favor of having a second on the left-pole. Every other (AZ, NV, MN, IL) seems to have adopted signal-per-lane strategies; nothing wrong with this per-se, but I don't know how necessary it is to have what can only be described as, perhaps, overkill, at some intersections in places like Nevada (though to be clear, this is still way better than MUTCD-standard placement, which is god-awful).

Off-topic: you may like this intersection in Spokane, WA. It has four examples of double-left turns that swap having two overhead left turn signals, for one overhead and one on the left. The supplemental signals also don't use backplates, which I personally prefer (reducing clutter). Plus, they use through-minus-one for signal placement.

I have to admit that my bias for this type of traffic signal is because I grew up in Los Angeles.  This was of course the standard of the signals of that era (1970's and 1980's).  And of course they made healthy use of double guy mast arms.  IMO, that's sufficient without being wasteful.  However, these days many newer installations are incorporating signal per lane in some areas of the state.

Here's a classic at Olympic and Prosser in West L.A.  Westbound there are 4 lanes of traffic* plus a left turn lane.  Yet only 3 signal faces.  Double guy mast arm.  The signals on Prosser got upgraded from 8-8-8 to 12-12-12, but the signals on Olympic haven't been changed in 50 years and IMO don't need to be.

https://www.google.com/maps/@34.048256,-118.4243816,3a,75y,234.33h,85.15t/data=!3m6!1e1!3m4!1sJm_ClrMmR-Lt8qnG2NL5Bg!2e0!7i16384!8i8192


Generally it is better to have too many signal faces rather than too few.  As you sometimes visit this area, you know that in Northern Virginia and Suburban Maryland post-mounted signals are rare, as these are areas that usually incorporated span wire until the recent past.  THey simply replaced the span wire with masts, but kept the signal at the same height, over the center of the street.  Both signal heads get blocked if you're behind a truck or bus.  And when making a permissive left turn, I find that I have to constantly turn my head from the signal to the corner to find a safe time to turn.  The left corner signal face is really useful, too bad that only a handful of states mandate it!

[DC has the opposite problem.  Pole mounted signals at every intersection, but even very wide streets do not have mast arms, or have very short mast arms.  I find the signals there to be quite weird.]

There is a downside to having too many signal faces.  First, you're wasting taxpayer money.  Second, to the extent that intersections are placed close together, you could have the problem that drivers may not know which signal if meant for them.  Utilizing 3m signals or louvers can help to block out the further signal, but not every place uses them.

* Three lanes of traffic with fourth Lane available doing afternoon Rush hour.  Realistically very few people Park here and the 4th Lane is generally always use for traffic.   I am still not convinced as to how I should treat Rush hour Lanes with regards to the x-1 rule above.  I think I will treat it as a moving lane under most circumstances.

roadfro

Quote from: mrsman on July 14, 2019, 10:08:51 AM
McDowell/44th:  The new signals definitely look very sturdy and professional, but to me I just think there are more signal heads than necessary.  For a dual left turn lane, there are two left singal heads on the mast and one of the streetlight on the left corner.  And for 3 thru lanes, there are three overhead signal heads on the mast and one on the streetlight.  To me this is overkill.

As I mentioned earlier, I like the old California style.  I would have one left turn signal on the mast and one on the streetlight.  One thru signal on the streetlight, and at most two thru signals on the mast.

[The old CA style would have only one thru signal on the mast, but I can admit that this is a wide street so two signal heads may be appropriate, but not 3.]

If I had to generalize rules for appropriate signal head placement, I would say:

Two signal faces for every unique signalized movement, period.  Regardless of the movement.

If there are no special signals for turns, there should be a signal face at left corner, and one at the right corner.  If there are X thru lanes, there should also be X-1 signals on the mast.  [0 mast signals for one thru lane, 1 mast signal for 2 thru lanes, 2 mast signals for 3 thru lanes etc.]  Exception: 1 thru lane and 1 left turn lane will also include 1 signal on the mast.

If there are also signals for right turn movements that also contain the thru movement (doghouse, 5 aspect straight line), the signal face at the right corner should also have the right turn signal aspect.  There should also be a near side signal face that is equivalent.

If there are also signals for right turn movements that are unique (FYA or RA-YA-GA), one should be on the near side corner and one should be on the far side right corner.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  [These signals are relatively rare, and usually only used when there are heavy pedestrian movements.]

If there are also signals for left turn movements that also contain the thru movement (doghouse, 4 aspect straight line, 5 aspect straight line), the signal face at the far left corner should also have the left turn signal aspect.  The left most signal on the mast should also have a left turn signal aspect. 

If there are also signals for left turn movements that are unique (FYA or RA-YA-GA), one should be on the far left corner and one should be on the mast.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  (If there are theree or more left turn lanes, an additional left turn signal on the mast is appropriate).

Just a terminology FYI: The 'mast' is the traffic signal's vertical support pole (like the main vertical support of the sails on a sailing ship), and 'mast arm' is the horizontal pole that holds most of the overhead signal heads. (You used "mast" to refer to the horizontal and "streetlight" to refer to the vertical.)
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

steviep24


mrsman

Most of the traffic signals in Downtown LA use curved mast arms, but here is one with double guy mast arms on a one-way street, on both sides of the street.

Note the symmetry.  5th/Wall:

https://www.google.com/maps/@34.0448865,-118.2458672,3a,75y,320.98h,97.52t/data=!3m6!1e1!3m4!1s4rdnXaUrqGqGAQBCjgVlyw!2e0!7i16384!8i8192

roadman65

I used to see a lot of these in NJ growing up.  Some are still around, but a very few have the poles planted in the ground instead of using bolts to secure them.
https://www.flickr.com/photos/54480415@N08/8500921274/in/album-72157632833956641/

Then you have some double guys still left that use bolted poles as well.

https://www.flickr.com/photos/54480415@N08/8500844534/in/album-72157632833956641/

NJ always used a third guy as well as if you look both signals have two guys and a third bar to support the weight of the signal heads.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

SidS1045

Quote from: roadman65 on July 08, 2019, 11:05:07 AM...the city does not use the detector loops to control the timing and uses a default timer as well.

Not everywhere.  On the one-way N-S avenues in Manhattan, they use somewhat primitive computer controls to make sure the green lights cascade to help enforce the 25mph city speed limit.  On Queens Boulevard they had tried, some years back, a more complicated form of computer control using cameras and detection loops to try to make traffic flow better and to respond more quickly to impediments such as double-parking and construction zones.  Not sure if that's still in place.
"A nation of sheep will beget a government of wolves." - Edward R. Murrow

Mark68

Quote from: mrsman on July 14, 2019, 05:29:35 PM
Quote from: jakeroot on July 14, 2019, 04:53:07 PM
Quote from: mrsman on July 14, 2019, 10:08:51 AM
McDowell/44th:  The new signals definitely look very sturdy and professional, but to me I just think there are more signal heads than necessary.  For a dual left turn lane, there are two left singal heads on the mast and one of the streetlight on the left corner.  And for 3 thru lanes, there are three overhead signal heads on the mast and one on the streetlight.  To me this is overkill.

As I mentioned earlier, I like the old California style.  I would have one left turn signal on the mast and one on the streetlight.  One thru signal on the streetlight, and at most two thru signals on the mast.

[The old CA style would have only one thru signal on the mast, but I can admit that this is a wide street so two signal heads may be appropriate, but not 3.]

If I had to generalize rules for appropriate signal head placement, I would say:

Two signal faces for every unique signalized movement, period.  Regardless of the movement.

If there are no special signals for turns, there should be a signal face at left corner, and one at the right corner.  If there are X thru lanes, there should also be X-1 signals on the mast.  [0 mast signals for one thru lane, 1 mast signal for 2 thru lanes, 2 mast signals for 3 thru lanes etc.]  Exception: 1 thru lane and 1 left turn lane will also include 1 signal on the mast.

If there are also signals for right turn movements that also contain the thru movement (doghouse, 5 aspect straight line), the signal face at the right corner should also have the right turn signal aspect.  There should also be a near side signal face that is equivalent.

If there are also signals for right turn movements that are unique (FYA or RA-YA-GA), one should be on the near side corner and one should be on the far side right corner.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  [These signals are relatively rare, and usually only used when there are heavy pedestrian movements.]

If there are also signals for left turn movements that also contain the thru movement (doghouse, 4 aspect straight line, 5 aspect straight line), the signal face at the far left corner should also have the left turn signal aspect.  The left most signal on the mast should also have a left turn signal aspect. 

If there are also signals for left turn movements that are unique (FYA or RA-YA-GA), one should be on the far left corner and one should be on the mast.  But be sure to maintain at least two signals for the straight movement, so this may require an additional straight signal on the mast.  (If there are theree or more left turn lanes, an additional left turn signal on the mast is appropriate).

For your third-to-last suggestion (unique right turn signal), I agree with your suggestions, except that a second pole-mounted signal could be used on the far-side of the intersection. They could be placed right next to each other, perhaps appearing as one giant 6- (or 7-) face signal.

I think we would get along very nicely! I agree with all of your suggestions. CA has managed to figure out a remarkable feat: signalizing massive intersections (20-30 approach lanes) without having them appear too cluttered. Good signal spacing, backplates (so the signals don't get lost), two signals for every movement, overhead signals using through-minus-one as a base (though there are plenty with only one overhead for three approach lanes; hell, I've seen one overhead for four through lanes!), and so on. Very impressive attention to detail.

I don't know of any state that signalizes their intersections like California. CO is probably the closest, in that they often drop a second left turn signal overhead, in favor of having a second on the left-pole. Every other (AZ, NV, MN, IL) seems to have adopted signal-per-lane strategies; nothing wrong with this per-se, but I don't know how necessary it is to have what can only be described as, perhaps, overkill, at some intersections in places like Nevada (though to be clear, this is still way better than MUTCD-standard placement, which is god-awful).

Off-topic: you may like this intersection in Spokane, WA. It has four examples of double-left turns that swap having two overhead left turn signals, for one overhead and one on the left. The supplemental signals also don't use backplates, which I personally prefer (reducing clutter). Plus, they use through-minus-one for signal placement.

I have to admit that my bias for this type of traffic signal is because I grew up in Los Angeles.  This was of course the standard of the signals of that era (1970's and 1980's).  And of course they made healthy use of double guy mast arms.  IMO, that's sufficient without being wasteful.  However, these days many newer installations are incorporating signal per lane in some areas of the state.

Here's a classic at Olympic and Prosser in West L.A.  Westbound there are 4 lanes of traffic* plus a left turn lane.  Yet only 3 signal faces.  Double guy mast arm.  The signals on Prosser got upgraded from 8-8-8 to 12-12-12, but the signals on Olympic haven't been changed in 50 years and IMO don't need to be.

https://www.google.com/maps/@34.048256,-118.4243816,3a,75y,234.33h,85.15t/data=!3m6!1e1!3m4!1sJm_ClrMmR-Lt8qnG2NL5Bg!2e0!7i16384!8i8192


Generally it is better to have too many signal faces rather than too few.  As you sometimes visit this area, you know that in Northern Virginia and Suburban Maryland post-mounted signals are rare, as these are areas that usually incorporated span wire until the recent past.  THey simply replaced the span wire with masts, but kept the signal at the same height, over the center of the street.  Both signal heads get blocked if you're behind a truck or bus.  And when making a permissive left turn, I find that I have to constantly turn my head from the signal to the corner to find a safe time to turn.  The left corner signal face is really useful, too bad that only a handful of states mandate it!

[DC has the opposite problem.  Pole mounted signals at every intersection, but even very wide streets do not have mast arms, or have very short mast arms.  I find the signals there to be quite weird.]

There is a downside to having too many signal faces.  First, you're wasting taxpayer money.  Second, to the extent that intersections are placed close together, you could have the problem that drivers may not know which signal if meant for them.  Utilizing 3m signals or louvers can help to block out the further signal, but not every place uses them.

* Three lanes of traffic with fourth Lane available doing afternoon Rush hour.  Realistically very few people Park here and the 4th Lane is generally always use for traffic.   I am still not convinced as to how I should treat Rush hour Lanes with regards to the x-1 rule above.  I think I will treat it as a moving lane under most circumstances.

One *minor* nitpick from me, and that is that beginning in the 1970s, I don't recall seeing any of the guy-wired mast arms being installed. I believe those were phased out in the late 60s. My memory goes back as far as 1974, when a traffic ight was installed using mast arms near where I was living at the time (at Culver & Walnut in Irvine), and most of the guy-wired installations I was seeing at the time already looked like they'd been around for years.
"When you come to a fork in the road, take it."~Yogi Berra



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