Traffic signal

[ztonyg]

https://goo.gl/maps/MvvU6VRMNepnJndW9
Noticed that NJ still uses the four section permissive left signal heads.  Are they the only state that uses these, as it seems that everywhere else I have been to uses either five sections or doghouse signal heads?

NYC occasionally installs them, so do municipalities on Long Island (mainly townships, the counties less so)

Scottsdale, Arizona uses them for most newer installations. ADOT (Arizona) also uses them.

[jakeroot]

How many intersections can there possibly be where a signal was downgraded all the way to an uncontrolled intersection?

A few years back, I posted about the weird abandoned signal equipment at 6th Ave NW and NW 47th St in Seattle, which seems to be a rather standard non-arterial intersection (apart from 6th Ave NW being a bit wider than normal) but which apparently had a signal at one point.

Now today, I stumbled on another one, at Carleton Ave S and S Willow St. Both of these streets are quite wide for a non-arterial (especially Carleton, which is wider than some arterials), so presumably they were once more important than they are now, but it still seems weird to think that it would ever have made sense to have a signal here!

So clearly the first of those (6th Ave NW and NW 47th St) is a bit more obvious, but great eyes catching the loop detectors. I don't think that's 'regulation' for unsignalized intersections!

Wonder if maybe the plan was to have Carleton be a one-way northbound street, to connect to the I-5 on-ramp? Corson would have been southbound. Of course, there's no evidence of this ever having been the case. Perhaps it was related to the former Boeing Field entrance that used to be at the east end of Willow? I know the intersection with Ellis was formerly signalized as well.

[US 89]

I saw this earlier this morning in Salt Lake City, and I can't say I've ever seen anything like the signal on the left:

[JoePCool14]

I saw this earlier this morning in Salt Lake City, and I can't say I've ever seen anything like the signal on the left:

I see what they were going for there, but that's probably not the most logical way to show that. I assume that there's a 90-degree right-turn lane, and then the left lane is all other movements. What would be clearer is a 3-section signal on the right solely for 90-degree right turns, and then because everything else is out of one lane, you would need to just use a red ball. You could also use a separate section with the 45-degree arrows, but I'm not sure if that's allowed per-say.

Do you have a GMSV link to that?

EDIT: Found it myself, but it's not updated.
https://goo.gl/maps/6LVBMWg1hJNLxwVT9

[jay8g]

So clearly the first of those (6th Ave NW and NW 47th St) is a bit more obvious, but great eyes catching the loop detectors. I don't think that's 'regulation' for unsignalized intersections!

Wonder if maybe the plan was to have Carleton be a one-way northbound street, to connect to the I-5 on-ramp? Corson would have been southbound. Of course, there's no evidence of this ever having been the case. Perhaps it was related to the former Boeing Field entrance that used to be at the east end of Willow? I know the intersection with Ellis was formerly signalized as well.

It would certainly make sense for Willow to have been signalized when it became a Boeing Field entrance -- I hadn't caught that looking through the aerials! Carleton as a major street probably dates back to before the I-5 ramp, though, since it led to the old 8th Ave S South Park Bridge (I can't figure out how to get a nice link like you had, but it's visible in the 1936 aerial image). Clearly, there was a real effort at some point to make Carleton not a through arterial, with all of the traffic circles and the turn restrictions at the I-5 ramp, so that's probably when the signals came out.

[fwydriver405]

https://goo.gl/maps/MvvU6VRMNepnJndW9
Noticed that NJ still uses the four section permissive left signal heads.  Are they the only state that uses these, as it seems that everywhere else I have been to uses either five sections or doghouse signal heads?

I believe it is standard for NHDOT and RIDOT to use 4-section bimodal signals for both left and right turn movements. NHDOT doesn't usually use this as a left turn signal unless it is split phased, as they have started to use FYA as a standard permissive/protected left turn signal head.

MaineDOT (and their contractors) usually install doghouse signal heads for both left and right turn movements, however, they will use the 4-section bimodal signals from time to time. From what I'm told, they use 4-section bimodal signal heads in Maine if load (on the mast arm) or height is an issue

I believe MassDOT is the same way as MaineDOT, but I'm not 100 % sure about that, as I've seen more doghouses than 4-section bimodal signals in MA on both older and newer installations.

[jakeroot]

So clearly the first of those (6th Ave NW and NW 47th St) is a bit more obvious, but great eyes catching the loop detectors. I don't think that's 'regulation' for unsignalized intersections!

Wonder if maybe the plan was to have Carleton be a one-way northbound street, to connect to the I-5 on-ramp? Corson would have been southbound. Of course, there's no evidence of this ever having been the case. Perhaps it was related to the former Boeing Field entrance that used to be at the east end of Willow? I know the intersection with Ellis was formerly signalized as well.

It would certainly make sense for Willow to have been signalized when it became a Boeing Field entrance -- I hadn't caught that looking through the aerials! Carleton as a major street probably dates back to before the I-5 ramp, though, since it led to the old 8th Ave S South Park Bridge (I can't figure out how to get a nice link like you had, but it's visible in the 1936 aerial image). Clearly, there was a real effort at some point to make Carleton not a through arterial, with all of the traffic circles and the turn restrictions at the I-5 ramp, so that's probably when the signals came out.

For a nice link to Historic Aerials, hit the Twitter button, and copy the link that it generates. Seems to work for me, but make sure the year is correct in the link.

It is interesting that in both of your examples, calming circles are what replaced the signals. I guess I'd be curious to know if the calming circles replaced the signals immediately, or if the calming circles came later. I know they became really common in the '70s and '80s.

I'll sift through my newspaper archives this afternoon to see if I can figure out when those signals were removed. It's surprisingly common to see these things mentioned in newspaper articles.

[ztonyg]

https://goo.gl/maps/MvvU6VRMNepnJndW9
Noticed that NJ still uses the four section permissive left signal heads.  Are they the only state that uses these, as it seems that everywhere else I have been to uses either five sections or doghouse signal heads?

I believe it is standard for NHDOT and RIDOT to use 4-section bimodal signals for both left and right turn movements. NHDOT doesn't usually use this as a left turn signal unless it is split phased, as they have started to use FYA as a standard permissive/protected left turn signal head.

MaineDOT (and their contractors) usually install doghouse signal heads for both left and right turn movements, however, they will use the 4-section bimodal signals from time to time. From what I'm told, they use 4-section bimodal signal heads in Maine if load (on the mast arm) or height is an issue

I believe MassDOT is the same way as MaineDOT, but I'm not 100 % sure about that, as I've seen more doghouses than 4-section bimodal signals in MA on both older and newer installations.

4-section bimodals are very common in Kansas (especially the Kansas City suburbs).

[plain]

Some rather interesting signals at this intersection in Roanoke, VA

https://maps.app.goo.gl/G6GdCd3q36czEvvf7

[jakeroot]

Some rather interesting signals at this intersection in Roanoke, VA

https://maps.app.goo.gl/G6GdCd3q36czEvvf7

Reminds me of the signals I see around here in Tacoma. For years, the standard display was 8-8-8, but then 12-8-8; in both cases, arrows were almost always 12 inch. Several examples like yours here, here, here, and here.

[Big John]

^^ 1971 MUTCD banned new installations of 8" arrows.

[plain]

Some rather interesting signals at this intersection in Roanoke, VA

https://maps.app.goo.gl/G6GdCd3q36czEvvf7

Reminds me of the signals I see around here in Tacoma. For years, the standard display was 8-8-8, but then 12-8-8; in both cases, arrows were almost always 12 inch. Several examples like yours here, here, here, and here.

Great examples. That closest 5-section in the last link is pretty ugly though

There are still a few 12-8-8 and a couple 12-8-8-12 signals left around VA. 12-8-12, however, is very rare, especially after the king of such (Hampton) decided to eliminate all of theirs.

[Old Dominionite]

Some rather interesting signals at this intersection in Roanoke, VA

https://maps.app.goo.gl/G6GdCd3q36czEvvf7

Reminds me of the signals I see around here in Tacoma. For years, the standard display was 8-8-8, but then 12-8-8; in both cases, arrows were almost always 12 inch. Several examples like yours here, here, here, and here.

Great examples. That closest 5-section in the last link is pretty ugly though

There are still a few 12-8-8 and a couple 12-8-8-12 signals left around VA. 12-8-12, however, is very rare, especially after the king of such (Hampton) decided to eliminate all of theirs.

Alexandria City had a few prominent 12-8-12 assemblies along Duke St in the West End that lasted until the late 2000s/early 2010s. The cities in Virginia are where you can still hope to find some traffic signal gems. The rest of the state is dominated by VDOT 12-12-12 monotony.

[ErmineNotyours]

^^ 1971 MUTCD banned new installations of 8" arrows.

The traffic lights were completely redone in Downtown Renton in 1973, with 8" arrows.  The few remaining ones are endangered as they're replacing the lights again and making the streets two way.

[jeffandnicole]

^^ 1971 MUTCD banned new installations of 8" arrows.

Nearly everything that has been banned over the years still finds a way into the field.

[Amtrakprod]

https://goo.gl/maps/MvvU6VRMNepnJndW9
Noticed that NJ still uses the four section permissive left signal heads.  Are they the only state that uses these, as it seems that everywhere else I have been to uses either five sections or doghouse signal heads?

I believe it is standard for NHDOT and RIDOT to use 4-section bimodal signals for both left and right turn movements. NHDOT doesn't usually use this as a left turn signal unless it is split phased, as they have started to use FYA as a standard permissive/protected left turn signal head.

MaineDOT (and their contractors) usually install doghouse signal heads for both left and right turn movements, however, they will use the 4-section bimodal signals from time to time. From what I'm told, they use 4-section bimodal signal heads in Maine if load (on the mast arm) or height is an issue

I believe MassDOT is the same way as MaineDOT, but I'm not 100 % sure about that, as I've seen more doghouses than 4-section bimodal signals in MA on both older and newer installations.

MassDOT does not use 4 section bi model signals any more. If there is a left turn lane, 4 section FYAs will be used. If not, then a doghouse will be used. Doghouses are the default for right turn signals as well.


iPhone

[EpicRoadways]

Some VERY Missouri-Style traffic lights in Missouri's neighbor to the north.

[SkyPesos]

Continuing the lead-lag phasing from the FYA thread to not derail that thread that much

@jeffandnicole: true, well said

Lead-lag is pretty common with left turns I've seen in the St Louis area, both protected and protected/permissive. If you drive through an area frequently, it's easy to tell which side gets the leading left, and which side gets the lagging left, as it's generally consistent.

In some places near my hometown, like South Portland, also both with protected only and beginning with FYA, on some corridors during the weekday rush hour, the lead-lag alternates depending on the time of day. IIRC, the peak direction gets the leading left and the non-peak direction gets the lagging left, but not sure if that is true or flipped around. Not sure if this kind of time of day lead-lag is common in other cities.

From what I've seen it's more about ensuring the two mainroad straight movements get "green bands" through the whole corridor (don't have to stop of they keep going straight).  So based on the cycle length (which is based on overall volumes) the lefts are really an afterthought, dictated by those straight platoons.  Sometimes the busy left will lead, sometimes lag.  But generally leading one and lagging the other makes those straight movements stop the least (depending on space to next signal, speed limit, etc). So certain times of day it may make most sense for the same movement to lead and later in the day lag.

Kind of wondering, how common is it for SPUI interchanges to operate under a lead-lag configuration for the left turn on-ramps? I mentioned St Louis's as an example above, with a couple of them I've been on a lot when I lived in the area (I-170 and MO 340, I-270 and MO 340, I-70 and MO 94) using lead-lag. If what is said about the straight movements getting more green light time, my examples would make sense, as MO 340 is a busy arterial with lots of through traffic. Though outside of these, along with probably some more in the St Louis area, I haven't seen a SPUI on-ramp left turn using a lead-lag configuration yet.

[US 89]

Lead-lag phasing for left turn on-ramps seems to be quite common, if not the norm, at Utah SPUIs in my experience.

[roadfro]

Continuing the lead-lag phasing from the FYA thread to not derail that thread that much

@jeffandnicole: true, well said

Lead-lag is pretty common with left turns I've seen in the St Louis area, both protected and protected/permissive. If you drive through an area frequently, it's easy to tell which side gets the leading left, and which side gets the lagging left, as it's generally consistent.

In some places near my hometown, like South Portland, also both with protected only and beginning with FYA, on some corridors during the weekday rush hour, the lead-lag alternates depending on the time of day. IIRC, the peak direction gets the leading left and the non-peak direction gets the lagging left, but not sure if that is true or flipped around. Not sure if this kind of time of day lead-lag is common in other cities.

From what I've seen it's more about ensuring the two mainroad straight movements get "green bands" through the whole corridor (don't have to stop of they keep going straight).  So based on the cycle length (which is based on overall volumes) the lefts are really an afterthought, dictated by those straight platoons.  Sometimes the busy left will lead, sometimes lag.  But generally leading one and lagging the other makes those straight movements stop the least (depending on space to next signal, speed limit, etc). So certain times of day it may make most sense for the same movement to lead and later in the day lag.

Kind of wondering, how common is it for SPUI interchanges to operate under a lead-lag configuration for the left turn on-ramps? I mentioned St Louis's as an example above, with a couple of them I've been on a lot when I lived in the area (I-170 and MO 340, I-270 and MO 340, I-70 and MO 94) using lead-lag. If what is said about the straight movements getting more green light time, my examples would make sense, as MO 340 is a busy arterial with lots of through traffic. Though outside of these, along with probably some more in the St Louis area, I haven't seen a SPUI on-ramp left turn using a lead-lag configuration yet.

I think I've seen it a few times in the Las Vegas area.

When you think about it, it makes sense to have lead-lag at a SPUI if they're trying to get good signal progression through the arterial corridor. The SPUI will operate like any other signalized intersection with respect to phasing (just perhaps with longer yellow & red intervals due to intersection size). So if there's already lead-lag on the corridor, lead-lag at the SPUI is likely to provide the greatest progression overall.

[RestrictOnTheHanger]

Absurdly long visors at a 5 way intersection

https://maps.app.goo.gl/tDBJBuatBrHKHRD67

[Rothman]

See the visor on the right.

https://maps.app.goo.gl/TBEhEpnsVvP1VwqH6

[SignBridge]

Absurdly long visors at a 5 way intersection

https://maps.app.goo.gl/tDBJBuatBrHKHRD67

Those are angle visors used where roads converge at a fine angle. Their purpose is to prevent drivers on one road from seeing the signals for the other road. And yes they are exceptionally long.

[jakeroot]

Seems like limited-visibility signals (3M? Formerly, Intelites as well) might be an easy way to prevent long visors like those.

[SignBridge]

The visors are probably a lot less expensive.