Traffic signal

[jakeroot]

I like near-right corner supplemental signals. They are found at many intersections in California and I believe are standard in Wisconsin. I'd like to see them everywhere.

Oddly enough, I believe they're a requirement in Illinois as well.

According to an engineer friend, there was once a plan for the 2009 MUTCD to require near-side signals at all locations with 40-MPH approach speeds, but this was dropped. I would love to see this requirement considered again.

That's very dumb, but what really bothers me is the dual 4 sections both with left arrows. The left one should be a 3 second all left arrow and the right one should be a 3 section straight

It's a split-phased intersection with left, right, and straight through movements. The green orbs are a requirement.

I understand it's split phased, that doesn't change the fact of what I said. There are still green orbs, just matching the signals to the lane markings, which should be a requirement

I see. I interpreted your comment as wanting a three-section left arrow on the left, and a three section right arrow on the right...no idea why, since you clearly said nothing like that.

A three-section left turn arrow would work on the left, although ideally, there would be a second left-turn head on the mast to its immediate left. At least the current setup has a significant amount of redundancy.

[mrsman]

A sign along the lines of "No turn on solid red arrow" would be helpful, even though this rule is generally true in most states.

At one point, I started making a map of where certain red-light movements are allowed and prohibited, but I didn't get very far before running out of steam.  But I wonder how many states is "most states" w/r/t turning right on a red arrow.  I suppose it's possible that most states actually allow it–you know, not having actually tallied them up.

Not only that but in some states the law is ambiguous of whether you can turn or not on a red arrow.  In my mind, it seems like turning on red arrow is something that would only be allowed in states that are generally liberal on turning like WA and OR.

[Revive 755]

I like near-right corner supplemental signals. They are found at many intersections in California and I believe are standard in Wisconsin. I'd like to see them everywhere.

Oddly enough, I believe they're a requirement in Illinois as well.

Depends on the IDOT District and the roadway.  District 1 (Chicagoland) usually frowns on them for IDOT roadways if the roadway has less than three through lanes and no dedicated right turn lane.  Cook County though uses them all the time.  District 3 (Ottawa) will sometimes use a supplemental head on the mast arm shaft rather than a near right.

That's very dumb, but what really bothers me is the dual 4 sections both with left arrows. The left one should be a 3 second all left arrow and the right one should be a 3 section straight

It's a split-phased intersection with left, right, and straight through movements. The green orbs are a requirement.

I understand it's split phased, that doesn't change the fact of what I said. There are still green orbs, just matching the signals to the lane markings, which should be a requirement

I see. I interpreted your comment as wanting a three-section left arrow on the left, and a three section right arrow on the right...no idea why, since you clearly said nothing like that.

A three-section left turn arrow would work on the left, although ideally, there would be a second left-turn head on the mast to its immediate left. At least the current setup has a significant amount of redundancy.

There's a few of these types of setups in Lake County where split phased heads are used for dedicated left turn lanes instead of all arrow heads:
* SB Fairfield Road at Old McHenry Road
* NB Quentin Road at Old McHenry Road
* SB Delany Road at US 41

[jakeroot]

I like near-right corner supplemental signals. They are found at many intersections in California and I believe are standard in Wisconsin. I'd like to see them everywhere.

Oddly enough, I believe they're a requirement in Illinois as well.

Depends on the IDOT District and the roadway.  District 1 (Chicagoland) usually frowns on them for IDOT roadways if the roadway has less than three through lanes and no dedicated right turn lane.  Cook County though uses them all the time.  District 3 (Ottawa) will sometimes use a supplemental head on the mast arm shaft rather than a near right.

Oh, that's right. I spend so much time looking around Chicago on Street View, I forget that not all parts of Illinois use the same setup (with near-side signals). IIRC, there's at least one district that doesn't use any supplemental signals...does that sound right?

A three-section left turn arrow would work on the left, although ideally, there would be a second left-turn head on the mast to its immediate left. At least the current setup has a significant amount of redundancy.

There's a few of these types of setups in Lake County where split phased heads are used for dedicated left turn lanes instead of all arrow heads:
* SB Fairfield Road at Old McHenry Road
* NB Quentin Road at Old McHenry Road
* SB Delany Road at US 41

I would say that, in both British Columbia and Washington State, the vast majority of split-phased intersections (regardless if there's a dedicated left turn lane) use the 4-section signal with a green orb and green arrow. Seattle even has a variation with a bi-modal green+yellow arrow (even though the yellow orb does that job at split-phased lights). If I see a dedicated left turn signal (all-arrow display, or "LEFT TURN SIGNAL" in BC), it's pretty much guaranteed to be a regular-phased intersection.

What I also see in BC, where far-left supplemental signals are required (unlike WA), is that at split-phased intersections, there will be a single overhead 4-section display (with green arrow and green orb), a repeat of that signal on the far right pole (sometimes with a green left arrow, sometimes not), and a three-section all-arrow display on the far left pole. EDIT: here's one example in Mission: http://bit.ly/2v62z9P

[paulthemapguy]

The base IDOT requirement is one signal head per lane, and at least two signal heads per movement (e.g. left turn, right turn, or straight).  Each district may have different stylings that they typically follow, adhering to that general basic requirement, but none of those stylings are officially mandated anywhere, to my knowledge.  Thus, there's nothing requiring a signal head placed in any specific position at an intersection.  All IDOT cares is those two basic requirements.

[jakeroot]

There's a requirement for "one signal head per lane" in Illinois? I seem to recall seeing quite a few intersections, with permissive phasing, that had one signal fewer than the number of lanes. I also seem to remember quite a lot of signals that were like this.

[Revive 755]

I like near-right corner supplemental signals. They are found at many intersections in California and I believe are standard in Wisconsin. I'd like to see them everywhere.

Oddly enough, I believe they're a requirement in Illinois as well.

Depends on the IDOT District and the roadway.  District 1 (Chicagoland) usually frowns on them for IDOT roadways if the roadway has less than three through lanes and no dedicated right turn lane.  Cook County though uses them all the time.  District 3 (Ottawa) will sometimes use a supplemental head on the mast arm shaft rather than a near right.

Oh, that's right. I spend so much time looking around Chicago on Street View, I forget that not all parts of Illinois use the same setup (with near-side signals). IIRC, there's at least one district that doesn't use any supplemental signals...does that sound right?

District 8 (Collinsville) did not use to use supplemental heads for left turns.  Based on the few intersections I've checked, they did use supplemental near rights.

There's a requirement for "one signal head per lane" in Illinois? I seem to recall seeing quite a few intersections, with permissive phasing, that had one signal fewer than the number of lanes. I also seem to remember quite a lot of signals that were like this.

Some of the IDOT Districts, such as District 1 (Schaumburg) and District 4 (Peoria), possibly 5 (Paris) for older signals, seem to count supplemental heads towards meeting the ""one signal head per lane" requirement since for dual lefts there is only one left turn head on the mast arm and a supplement far left head.

The linked example on Dempster Street in Niles is an older installation that has not been updated yet - the use of the trussed ("trombone") arms is the best indication.

[paulthemapguy]

There's a requirement for "one signal head per lane" in Illinois? I seem to recall seeing quite a few intersections, with permissive phasing, that had one signal fewer than the number of lanes. I also seem to remember quite a lot of signals that were like this.

When I say one signal head per lane, I mean it literally.  At the intersection you gave as an example, there were two thru lanes and one left turn lane.  That's a total of three lanes, mandating a minimum of 3 signal heads for that approach.  I do not mean that each lane has to have a signal head directly ahead of each lane.  The requirement is more general than that- x lanes require a minimum of x signals, pure and simple.  No specifications on where exactly they are placed.

[jakeroot]

There's a requirement for "one signal head per lane" in Illinois? I seem to recall seeing quite a few intersections, with permissive phasing, that had one signal fewer than the number of lanes. I also seem to remember quite a lot of signals that were like this.

Some of the IDOT Districts, such as District 1 (Schaumburg) and District 4 (Peoria), possibly 5 (Paris) for older signals, seem to count supplemental heads towards meeting the ""one signal head per lane" requirement since for dual lefts there is only one left turn head on the mast arm and a supplement far left head.

The linked example on Dempster Street in Niles is an older installation that has not been updated yet - the use of the trussed ("trombone") arms is the best indication.

When I say one signal head per lane, I mean it literally.  At the intersection you gave as an example, there were two thru lanes and one left turn lane.  That's a total of three lanes, mandating a minimum of 3 signal heads for that approach.  I do not mean that each lane has to have a signal head directly ahead of each lane.  The requirement is more general than that- x lanes require a minimum of x signals, pure and simple.  No specifications on where exactly they are placed.

Thanks. That would explain why the example I linked to in Niles (above) was recently updated with new signals, but did not gain any new overhead signals.

I'm guessing IDOT's actual message is that there must be the same number of primary signals as lanes; "one signal per lane" is generally used to describe overhead signals. Though to be clear, I much prefer the Illinois rule. I don't understand the fascination with overhead signals. The Niles intersection I linked to above is excellent signal placement, IMO.

[MCRoads]

I dont know if this is where I should ask, but here goes!

I was wondering who to ask (and what to ask) to get a traffic light that is going to be retired. I have E-mailed several places (the city, the dot, a contractor in Denver) just asking about how to get a retired light. I haven't gotten any responses. Any suggestions?

*** Also I dont want to go on E-bay, I want a traffic light that just came out of a scrap heap, or off the pole. Not a $500 light that has been in a closet for 5 years. ***

[traffic light guy]

I dont know if this is where I should ask, but here goes!

I was wondering who to ask (and what to ask) to get a traffic light that is going to be retired. I have E-mailed several places (the city, the dot, a contractor in Denver) just asking about how to get a retired light. I haven't gotten any responses. Any suggestions?

*** Also I dont want to go on E-bay, I want a traffic light that just came out of a scrap heap, or off the pole. Not a $500 light that has been in a closet for 5 years. ***

What kind of signal is it

[MCRoads]

Any signal. Any type, make, model, doghouse, tower, regular old traffic light. Hell! Even a 4-way beacon would satisfy me!

[RobbieL2415]

An unusual sight on CT 32 in New London.

https://www.google.com/maps/@41.3782795,-72.1034484,3a,26.1y,347.98h,95.25t/data=!3m6!1e1!3m4!1snxDpOQpoxAKxQ0a8lXLvPA!2e0!7i13312!8i6656

[CJResotko]

T-Con 4-way beacon cluster in Bay City, Michigan. I think this is the only T-Con signal in the state of Michigan. (not my video): https://youtu.be/RHARNXlfp6c

[Revive 755]

I'm guessing IDOT's actual message is that there must be the same number of primary signals as lanes; "one signal per lane" is generally used to describe overhead signals. Though to be clear, I much prefer the Illinois rule. I don't understand the fascination with overhead signals. The Niles intersection I linked to above is excellent signal placement, IMO.

IMHO, it's better when the left turn head is at least on the edge of the left turn lane.  When it's on the lane line between the two through lanes or further to the right it becomes easier to loose site of.

[jakeroot]

I'm guessing IDOT's actual message is that there must be the same number of primary signals as lanes; "one signal per lane" is generally used to describe overhead signals. Though to be clear, I much prefer the Illinois rule. I don't understand the fascination with overhead signals. The Niles intersection I linked to above is excellent signal placement, IMO.

IMHO, it's better when the left turn head is at least on the edge of the left turn lane.  When it's on the lane line between the two through lanes or further to the right it becomes easier to loose site of.

But isn't there always a signal on the far left corner? At least in most IDOT districts. The overhead signal may not be as obvious, but there's always that pole-mounted signal on the left.

I am by no means opposed to having that 5-section tower be between the left and through lanes, though with the second left turn head on the left, I don't know how necessary it is to get it that far out. I think it might be better if it were centered over the arriving carriageway/roadway (so in the case of Dempster/Greenwood, centered over the center lane (aka the left through lane)).

[paulthemapguy]

But isn't there always a signal on the far left corner? At least in most IDOT districts. The overhead signal may not be as obvious, but there's always that pole-mounted signal on the left.

I am by no means opposed to having that 5-section tower be between the left and through lanes, though with the second left turn head on the left, I don't know how necessary it is to get it that far out. I think it might be better if it were centered over the arriving carriageway/roadway (so in the case of Dempster/Greenwood, centered over the center lane (aka the left through lane)).

IDOT will almost always have that signal on the far left corner, especially if there's a left turn indication.  In cases with left turn arrows, IDOT requires two separate signal heads to include them; one of them will almost always be a post-mounted signal on the far left corner.  On truck routes (note: pretty much every marked state highway is one of these), signal assemblies will include a signal head on the far left corner, whether there's a left turn phase of not, in case vehicles have to see around a truck that obscures the sight of mast-arm mounted signals.

Signal heads on mast arms that show left turn arrows will almost always be above the rightmost edge of the left turn lane.  There are two reasons for this:  saving a bit on materials because you don't need the mast arm to be quite as long, and refraining from obstructing the view the oncoming traffic needs to have, in order to see THEIR overhead signals.  I like having my signals directly in front of me as much as the next guy, but I get the reasons why they do this.

NOTE:  When I speak of IDOT's requirements, I'm speaking of requirements that apply to EVERY signal in the state, whether on a state-maintained road or not.  The infrastructure found on IDOT's marked roadways may be more robust, or adhere to a slightly different modus operandae than the stuff found on county or local roads.

[Revive 755]

Signal heads on mast arms that show left turn arrows will almost always be above the rightmost edge of the left turn lane.  There are two reasons for this:  saving a bit on materials because you don't need the mast arm to be quite as long, and refraining from obstructing the view the oncoming traffic needs to have, in order to see THEIR overhead signals.  I like having my signals directly in front of me as much as the next guy, but I get the reasons why they do this.

This only applies to IDOT signals in D-1 and most of the local agencies with the exceptions of Kane County, formerly McHenry County, and sometimes Naperville, which mount (or had been mounting) the left turn heads in front of the left turn lane.  The other IDOT Districts, with the possible exception of District 9 (Carbondale), usually mount the left turn head in front of the turn lane.

[23skidoo]

Here's something I found on YouTube recently that I thought might be interesting to you fellow signalheads. It's a video of Lansing, Michigan from the 1960s. Most of the signals in the video look to be then-new 8-8-8 clusters hanging on diagonal wire span (typical of Michigan at the time, even as recently as the 2000s). But then I saw something weird. From about 4:50-5:00, you'll see a pair of 8-8-8-8 4-way clusters on a wirespan somewhere near downtown Lansing:

https://www.youtube.com/watch?v=7Uns7ajf8Sc

I don't know what to make of these signals. I don't think I've ever seen anything quite like that in Michigan, except for some recently-installed left-turn signals. My guess is that second light turns yellow before it turns green. As evidence of this, the light appears to be yellow at about 4:55 before turning green at 4:59. Presumably the third light turns yellow after the green, but I suppose it could be a green arrow (but unlikely considering that arrows usually go under the solid green, see 5:31).

[Rick1962]

From about 4:50-5:00, you'll see a pair of 8-8-8-8 4-way clusters...

The topmost section could be for a flashing red for four-way stop. Sand Springs, Oklahoma used to have 12-8-8-8 signals downtown with the 8-inch sections for R-Y-G and the upper 12-inch for flashing red. They had to get the idea somewhere.

SM-T580

[index]

https://www.google.com/maps/@26.6937919,-80.0867966,3a,32.5y,63.51h,103.23t/data=!3m7!1e1!3m5!1s0fUmM6QtfeWnPURZCYwEbg!2e0!5s20170601T000000!7i13312!8i6656


Found this bizarre five section inverted T in Florida.


https://www.google.com/maps/@26.6938977,-80.0866671,3a,17.5y,205.01h,107.11t/data=!3m7!1e1!3m5!1sxzPLesbrjEHoBufGXzb0Fw!2e0!5s20181101T000000!7i13312!8i6656


They seem to just have taken another signal, and mounted it sideways on the bottom of the top two sections...Can't say I've seen anything like this before.

[plain]

https://www.google.com/maps/@26.6937919,-80.0867966,3a,32.5y,63.51h,103.23t/data=!3m7!1e1!3m5!1s0fUmM6QtfeWnPURZCYwEbg!2e0!5s20170601T000000!7i13312!8i6656


Found this bizarre five section inverted T in Florida.


https://www.google.com/maps/@26.6938977,-80.0866671,3a,17.5y,205.01h,107.11t/data=!3m7!1e1!3m5!1sxzPLesbrjEHoBufGXzb0Fw!2e0!5s20181101T000000!7i13312!8i6656


They seem to just have taken another signal, and mounted it sideways on the bottom of the top two sections...Can't say I've seen anything like this before.

I'm guessing all three lights on the bottom are green arrows (left/straight/right) and yeah I'm with you on this.. I've never seen anything like that either, in regards to both the layout and it's assembly.

EDIT: I have seen the bottom aspect mounted separately from the rest of the signal but with 2 lights, not 3.

[Revive 755]

^ The MUTCD used to show such a configuration - see Page 11/54 of https://ceprofs.civil.tamu.edu/ghawkins/MUTCD-History_files/1988%20MUTCD/4.Part_IV.Signals.pdf

[Revive 755]

Signal heads on mast arms that show left turn arrows will almost always be above the rightmost edge of the left turn lane.  There are two reasons for this:  saving a bit on materials because you don't need the mast arm to be quite as long, and refraining from obstructing the view the oncoming traffic needs to have, in order to see THEIR overhead signals.  I like having my signals directly in front of me as much as the next guy, but I get the reasons why they do this.

This only applies to IDOT signals in D-1 and most of the local agencies with the exceptions of Kane County, formerly McHenry County, and sometimes Naperville, which mount (or had been mounting) the left turn heads in front of the left turn lane.  The other IDOT Districts, with the possible exception of District 9 (Carbondale), usually mount the left turn head in front of the turn lane.

And apparently D-1 didn't follow this rule for the WB I-88 Exit to 22nd Street/Cermak in Oak Brook.  Streetview NB

SB also has only one far side head for the through movement.  Streetview

[Amtrakprod]

Signal heads on mast arms that show left turn arrows will almost always be above the rightmost edge of the left turn lane.  There are two reasons for this:  saving a bit on materials because you don't need the mast arm to be quite as long, and refraining from obstructing the view the oncoming traffic needs to have, in order to see THEIR overhead signals.  I like having my signals directly in front of me as much as the next guy, but I get the reasons why they do this.

This only applies to IDOT signals in D-1 and most of the local agencies with the exceptions of Kane County, formerly McHenry County, and sometimes Naperville, which mount (or had been mounting) the left turn heads in front of the left turn lane.  The other IDOT Districts, with the possible exception of District 9 (Carbondale), usually mount the left turn head in front of the turn lane.

And apparently D-1 didn't follow this rule for the WB I-88 Exit to 22nd Street/Cermak in Oak Brook.  Streetview NB

SB also has only one far side head for the through movement.  Streetview

Um I think that should be allowed, im for a signal directing the lane


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