Traffic signal

[fwydriver405]

Alternatively, delete the left-most right turn signal, placing it on the right-side mast, and replace that signal with a RYG orb signal.

This example from Portsmouth NH only has 2 lanes (left/thru, right), but if there was a second right turn lane in addition to what is present, something like this or this?

Actually, while looking for a signal for another thread, I think this signal in Salem, NH better fits the conditions above.

What is the point of the "no turn on red arrow" sign? It's a left turn, and it's not the type of intersection where someone would expect a left on red.

I'm not really sure what the point is but I do know that signage is older NHDOT standard, as most newer NHDOT-maintained signals have eliminated the sign completely. (Note that both signals I mentioned are town/city maintained, not NHDOT). If you look at the Portsmouth NH example on Woodbury Ave... you can see the contractor who installed the signal was following the older standard.

Having that sign there technically prohibits right on red as well... if the right turn signals are red arrows, which NH likes to do with 3-section protected right turn signals. That intersection and the Market St/Woodbury Ave intersection in Portsmouth have that problem as well, though most drivers I've seen just turn right on red at both intersections listed above.

[betfourteen]

https://goo.gl/maps/vi4hxXbyun6bpRTs9

This intersection has since been replaced, but I'm sure this old set up was not correct??

[plain]

https://goo.gl/maps/vi4hxXbyun6bpRTs9

This intersection has since been replaced, but I'm sure this old set up was not correct??

Very odd indeed. The red was not necessary during the green arrow at all given the fact that this is a T-intersection. Could've been just regular left turn signals, or just regular signals period (all orbs).

[SignBridge]

https://goo.gl/maps/vi4hxXbyun6bpRTs9

This intersection has since been replaced, but I'm sure this old set up was not correct

That looks like the intersection of Lawson and Daly Blvd's, correct? Yes there are newer signals there now.

[betfourteen]

https://goo.gl/maps/vi4hxXbyun6bpRTs9

This intersection has since been replaced, but I'm sure this old set up was not correct

That looks like the intersection of Lawson and Daly Blvd's, correct? Yes there are newer signals there now.

Yup, in Island Park/Oceanside.

[roadfro]

Found another SPUI without a single long mast arm in the center of the interchange at I-215 and Windmill in Vegas. This one has a mast arm on each triangle gore, which is a bit excessive imo.

The DO NOT ENTER on the street sign is a nice touch.

Sorry I'm late to the SPUI discussion, but wanted to comment on this.

The I-215 & Windmill SPUI that SkyPesos linked is, I believe, only the second SPUI in Nevada with intersection above the freeway. I'm fairly certain that this was the first SPUI design overseen by Clark County. When you compare to the next two "over" SPUIs the county built along I-215 at Green Valley Pkwy and Valley Verde Dr, as well as later "over" SPUIs along CC-215 at Town Center Dr, Far Hills Ave and Lake Mead Blvd, they all use a "two mast arms from the midpoint of the bridge" approach that somewhat mimics a monotube.

The first "over" SPUI in Nevada, by several years, was at I-15 & Cheyenne in North Las Vegas and constructed by NDOT. This one has both a monotube in the middle and redundant signals on the near side gore. This may seem excessive like an excessive amount of signal heads, but this interchange is different from the others, in that the bridge structure rises significantly over the surrounding terrain in short distance (as opposed to all the 215 examples where the freeway was built below grade leaving the bridge relatively level) causing sight distance issues to the signals.

Incidentally, every other "over" SPUI overseen by NDOT has used a monotube in the center. They even used a monotube at the "under" SPUI at US 95 & Rancho Dr in Las Vegas, instead of the usual method of attaching at least some of the primary signal heads to the bridge structure.


And to STLmapboy's comment: The "DO NOT ENTER" sign has become a standard. Other than the I-15 & Cheyenne example, you'll see that at every "over" SPUI in the Las Vegas area.

[SkyPesos]

Found another SPUI without a single long mast arm in the center of the interchange at I-215 and Windmill in Vegas. This one has a mast arm on each triangle gore, which is a bit excessive imo.

The DO NOT ENTER on the street sign is a nice touch.

Sorry I'm late to the SPUI discussion, but wanted to comment on this.

The I-215 & Windmill SPUI that SkyPesos linked is, I believe, only the second SPUI in Nevada with intersection above the freeway. I'm fairly certain that this was the first SPUI design overseen by Clark County. When you compare to the next two "over" SPUIs the county built along I-215 at Green Valley Pkwy and Valley Verde Dr, as well as later "over" SPUIs along CC-215 at Town Center Dr, Far Hills Ave and Lake Mead Blvd, they all use a "two mast arms from the midpoint of the bridge" approach that somewhat mimics a monotube.

The first "over" SPUI in Nevada, by several years, was at I-15 & Cheyenne in North Las Vegas and constructed by NDOT. This one has both a monotube in the middle and redundant signals on the near side gore. This may seem excessive like an excessive amount of signal heads, but this interchange is different from the others, in that the bridge structure rises significantly over the surrounding terrain in short distance (as opposed to all the 215 examples where the freeway was built below grade leaving the bridge relatively level) causing sight distance issues to the signals.

Incidentally, every other "over" SPUI overseen by NDOT has used a monotube in the center. They even used a monotube at the "under" SPUI at US 95 & Rancho Dr in Las Vegas, instead of the usual method of attaching at least some of the primary signal heads to the bridge structure.


And to STLmapboy's comment: The "DO NOT ENTER" sign has become a standard. Other than the I-15 & Cheyenne example, you'll see that at every "over" SPUI in the Las Vegas area.

I really like the two mast arms at the bridge midpoint signaling style too. It's less bulky than a monotube or truss gantry, and has the centering that it seems like most want with SPUIs. The first two I've seen with that style are both on I-64 in St. Louis, at Hampton and Kingshighway. Of course there's also ones with span wire that I see a lot in Indianapolis and Charlotte, but those are their own story.

For under SPUIs, I don't know any other example that has its own signal structure under the bridge besides the Rancho example you showed. Most examples have signals attached at either side of the bridge. But here's one I've gone through a lot that has all horizontal signals under the bridge, like the Rancho one: I-170 and MO 340 . It looks like there's two mast arms attached to the bridge that bends in the middle to accommodate the off ramp left turn signals.

EDIT: I forgot about I-170 and MO 180 when writing this, but it has its own signal structure for an under SPUI. Also in St. Louis, MO 141/MO 100 and I-70/Florissant are similar to the I-170/MO 340 I posted above. And there's I-64 and US 67, which is unique in that there's no overhead or on-bridge signals for the off ramp left movements; all signals for that movement are ground mounted.

[betfourteen]

I've always loved this set up at this interesection.

https://goo.gl/maps/2cRgpbtZgHeUrRJb7

[SkyPesos]

I've always loved this set up at this interesection.

https://goo.gl/maps/2cRgpbtZgHeUrRJb7

How often do the signs in the middle of that SPUI get knocked down? I imagine it would be pretty frequent.

And I thought that layout looked familiar to something in the St Louis area, with the single signal under the bridge. Eventually found it at the IL 255 interchange with IL 111/140.

[roadfro]

I've always loved this set up at this interesection.

https://goo.gl/maps/2cRgpbtZgHeUrRJb7

How often do the signs in the middle of that SPUI get knocked down? I imagine it would be pretty frequent.

Not sure about that particular intersection, but the two SPUIs in Reno, NV with a similar setup had those signs in the middle knocked down quite frequently. I think they stopped replacing them after a while...and when one of the intersections was repaved recently, the median was removed.

[ErmineNotyours]

US 101 & Blake Black Lake Blvd.

This is the only under SPUI I've ever been through, and I thought they were all set up this way.  The ramps also have advanced signals. The last time I drove this, I saw the yellow on the ramp and prepared to stop, but the car in front of me kept going.  Then they saw the red light and stopped right at it, blocking through traffic.  A second later they figured it out, and went through the intersection.  Ugh.

[jakeroot]

US 101 & Blake Lake Blvd.

This is the only under SPUI I've ever been through, and I thought they were all set up this way.  The ramps also have advanced signals. The last time I drove this, I saw the yellow on the ramp and prepared to stop, but the car in front of me kept going.  Then they saw the red light and stopped right at it, blocking through traffic.  A second later they figured it out, and went through the intersection.  Ugh.

This is definitely WSDOT's worst under-SPUI, in terms of signalization. There are much better ones in the Southwest District, like I-5 at NE 99th in Vancouver. The mid-way signals, attached to the overpass, are 3Ms which should help prevent cars from stopping at them.

[SkyPesos]

US 101 & Blake Lake Blvd.

This is the only under SPUI I've ever been through, and I thought they were all set up this way.  The ramps also have advanced signals. The last time I drove this, I saw the yellow on the ramp and prepared to stop, but the car in front of me kept going.  Then they saw the red light and stopped right at it, blocking through traffic.  A second later they figured it out, and went through the intersection.  Ugh.

The mast arm setup in the triangular gore for the exit ramps is unique; never seen that before. It may be a bit excessive, but it's better than being under-signalized like what I mentioned above for the I-64 and US 67 in St Louis SPUI; only one left turn signal before the overpass. The other two are on vertical poles under the bridge, sometimes difficult to see. Installing two off ramp left turn signals on the overpass structure would help greatly.

[jakeroot]

Related to the above discussion about SPUIs with regular mast arms:

Along the 51 Freeway in Phoenix, many interchanges are over-SPUIs with mast arms instead of monotubes:

(1) Bethany Home Road
(2) Glendale Ave
(3) Shea Blvd
(4) Cactus Road
(5) Greenway Road
(6) Bell Road
(7) Union Hills Drive

I personally think these are all excellent setups. Most even include the oft-forgotten right-side far-corner repeater signal required in many jurisdictions, something even California sometimes forgoes using.

Interestingly, the few that include double right turns from the off-ramps use yield signs instead of signals, such as at Bell Rd and the under-SPUI at Thomas Rd.

[SkyPesos]

Related to the above discussion about SPUIs with regular mast arms:

Along the 51 Freeway in Phoenix, many interchanges are over-SPUIs with mast arms instead of monotubes:

(1) Bethany Home Road
(2) Glendale Ave
(3) Shea Blvd
(4) Cactus Road
(5) Greenway Road
(6) Bell Road
(7) Union Hills Drive

I personally think these are all excellent setups. Most even include the oft-forgotten right-side far-corner repeater signal required in many jurisdictions, something even California sometimes forgoes using.

Interestingly, the few that include double right turns from the off-ramps use yield signs instead of signals, such as at Bell Rd and the under-SPUI at Thomas Rd.

I really like the signaling for those Phoenix ones, could be up there with the various St Louis examples I posted earlier as my preferences. Mast arms are noticeably shorter than the St Louis ones, but I think that's has to do with MoDOT installing an overhead signal for each lane, instead of like CA and AZ using a single overhead left signal for two left turn lanes. My only nitpick about the Phoenix ones is the lack of overhead signals for the left turns off the ramp, but that can easily be fixed with what is there currently.

[jakeroot]

I really like the signaling for those Phoenix ones, could be up there with the various St Louis examples I posted earlier as my preferences. Mast arms are noticeably shorter than the St Louis ones, but I think that's has to do with MoDOT installing an overhead signal for each lane, instead of like CA and AZ using a single overhead left signal for two left turn lanes. My only nitpick about the Phoenix ones is the lack of overhead signals for the left turns off the ramp, but that can easily be fixed with what is there currently.

They could stand to have a single overhead signal at the ends of the mast arms, angled towards the off-ramps. Something like this, just at the end of the arm.

That said, even having only post-mounted signals for the off-ramps, I feel like signal visibility is quite excellent. There are four signals, after all.

[roadfro]

I really like the signaling for those Phoenix ones, could be up there with the various St Louis examples I posted earlier as my preferences. Mast arms are noticeably shorter than the St Louis ones, but I think that's has to do with MoDOT installing an overhead signal for each lane, instead of like CA and AZ using a single overhead left signal for two left turn lanes. My only nitpick about the Phoenix ones is the lack of overhead signals for the left turns off the ramp, but that can easily be fixed with what is there currently.

They could stand to have a single overhead signal at the ends of the mast arms, angled towards the off-ramps. Something like this, just at the end of the arm.

That said, even having only post-mounted signals for the off-ramps, I feel like signal visibility is quite excellent. There are four signals, after all.

I'd have gone with one or two signal heads on the backside of the closer arterial mast arm, as with many of the Vegas area examples I posted.

It seems odd that there are not overhead signal heads for those Phoenix off ramps. And I wonder if the post-mounted signals on the far side of the interchange are too far away for the primary signal faces...

[Caps81943]

US 101 & Blake Lake Blvd.

This is the only under SPUI I've ever been through, and I thought they were all set up this way.  The ramps also have advanced signals. The last time I drove this, I saw the yellow on the ramp and prepared to stop, but the car in front of me kept going.  Then they saw the red light and stopped right at it, blocking through traffic.  A second later they figured it out, and went through the intersection.  Ugh.

This is definitely WSDOT's worst under-SPUI, in terms of signalization. There are much better ones in the Southwest District, like I-5 at NE 99th in Vancouver. The mid-way signals, attached to the overpass, are 3Ms which should help prevent cars from stopping at them.

Yeah, I am not a fan of that "island" in the middle. Seems a little dangerous.

[SkyPesos]

I really like the signaling for those Phoenix ones, could be up there with the various St Louis examples I posted earlier as my preferences. Mast arms are noticeably shorter than the St Louis ones, but I think that's has to do with MoDOT installing an overhead signal for each lane, instead of like CA and AZ using a single overhead left signal for two left turn lanes. My only nitpick about the Phoenix ones is the lack of overhead signals for the left turns off the ramp, but that can easily be fixed with what is there currently.

They could stand to have a single overhead signal at the ends of the mast arms, angled towards the off-ramps. Something like this, just at the end of the arm.

That said, even having only post-mounted signals for the off-ramps, I feel like signal visibility is quite excellent. There are four signals, after all.

I'd have gone with one or two signal heads on the backside of the closer arterial mast arm, as with many of the Vegas area examples I posted.

It seems odd that there are not overhead signal heads for those Phoenix off ramps. And I wonder if the post-mounted signals on the far side of the interchange are too far away for the primary signal faces...

I'll do a side by side comparison of 2 interchanges (one over, one under) without overhead signals; you can judge for yourself. Both on the default zoom setting of GSV. From what I see, it's sort of difficult to see the signals across the street without zooming in from that position, which may be a visibility issue for some drivers.

AZ 51 and Greenway (Phoenix)


I-64 and US 67 (St. Louis)

[roadfro]

US 101 & Blake Lake Blvd.

This is the only under SPUI I've ever been through, and I thought they were all set up this way.  The ramps also have advanced signals. The last time I drove this, I saw the yellow on the ramp and prepared to stop, but the car in front of me kept going.  Then they saw the red light and stopped right at it, blocking through traffic.  A second later they figured it out, and went through the intersection.  Ugh.

This is definitely WSDOT's worst under-SPUI, in terms of signalization. There are much better ones in the Southwest District, like I-5 at NE 99th in Vancouver. The mid-way signals, attached to the overpass, are 3Ms which should help prevent cars from stopping at them.

Yeah, I am not a fan of that "island" in the middle. Seems a little dangerous.

The island is there to help channelize the turns to prevent drifting into the oncoming left turns. The most dangerous thing about it is not necessarily the island itself, but rather the sign on the island when it gets knocked down.

[Amtrakprod]

Unique signal in Cambridge MA


iPhone

[plain]

Unique signal in Cambridge MA


iPhone

Looks like MA out DC'd DC lmao. Seriously, if someone from DC's engineering department saw this FYA, I wouldn't at all be surprised if something real similar appears there.

[jakeroot]

https://uploads.tapatalk-cdn.com/20210216/3bc9ea21733c454c93168363cfa5a1ae.jpg
Unique signal in Cambridge MA

Looks like MA out DC'd DC lmao. Seriously, if someone from DC's engineering department saw this FYA, I wouldn't at all be surprised if something real similar appears there.

Look no further than H St @ Bladensburg Rd NE. Nearly the same, although it's bottom aligned.

[plain]

https://uploads.tapatalk-cdn.com/20210216/3bc9ea21733c454c93168363cfa5a1ae.jpg
Unique signal in Cambridge MA

Looks like MA out DC'd DC lmao. Seriously, if someone from DC's engineering department saw this FYA, I wouldn't at all be surprised if something real similar appears there.

Look no further than H St @ Bladensburg Rd NE. Nearly the same, although it's bottom aligned.

Ahh nice!! It's been a couple of years since I've been on the city streets in DC. How common is that setup there?

[jakeroot]

https://uploads.tapatalk-cdn.com/20210216/3bc9ea21733c454c93168363cfa5a1ae.jpg
Unique signal in Cambridge MA

Looks like MA out DC'd DC lmao. Seriously, if someone from DC's engineering department saw this FYA, I wouldn't at all be surprised if something real similar appears there.

Look no further than H St @ Bladensburg Rd NE. Nearly the same, although it's bottom aligned.

Ahh nice!! It's been a couple of years since I've been on the city streets in DC. How common is that setup there?

This seems to be the only flashing yellow arrow for left turns in DC, at least that I know of. But I haven't been in the district proper since last July, and I didn't do much driving, so that may easily no longer be the case.