US traffic lights that don't have 2 'thru' signals.

[roadfro]

Here's one installed more recently, circa 2006: Reno, NV. Plumb Lane at Matley Lane (I-580/US 395 Southbound frontage/ramp)
https://www.google.com/maps/@39.506194,-119.780868,3a,21.4y,180.55h,91.32t/data=!3m4!1e1!3m2!1spiCDrLZaYvWGmGyAn4J4vA!2e0
(Zoom out to see the geometry and other signal heads on the approach)

This is an interesting intersection. It was formerly a tight diamond with through configuration, that had awful backups during peak hours (Plumb is a major arterial to the west, feeds into the Reno airport entrance just east of here). In 2006, NDOT & RTC converted this to a modified SPUI with through configuration, but shoehorned it in to the existing diamond footprint so as to not make any modifications to the freeway viaduct structure.

The left turns at this SPUI never go together in any direction (due to geometry and traffic volumes), so it essentially runs on a split phasing. For for the southbound direction linked here, the through movement always comes on with the left turn (the southbound right turn comes on at the same time plus overlaps with the eastbound to northbound left turn). Even still, the use three left turn heads and only one through head is baffling given that, since the at least the 1990s, it has been standard practice for new signals in Nevada to provide 2 signal heads for *every* movement regardless of what is the major movement.

[Roadrunner75]

What about requirements for number of signals that must visible from the stop bar - i.e. - number of through signals a certain distance within or across the intersection that can be viewed by the lead car at the stop bar.  I can't stand when I'm the lead car and there is either one or no signals (have to look almost straight up) that are easily visible.  I'm too lazy to look in MUTCD right now for anything on this so I will rely on others.

Here's another similar example that I can't stand on NJ 440 in Jersey City.  At the stop bar, the only signals visible are above the opposing lanes on a divided road or just pole mounted to one side.  On a road with this much traffic, only overhead signals across the intersection will do.
https://maps.google.com/maps?ll=40.706423,-74.099261&spn=0.000004,0.00327&t=m&z=19&layer=c&cbll=40.706531,-74.099778&panoid=0paxL2rt-GRGvkET4s8SyQ&cbp=12,168.32,,0,0.11

[roadfro]

There is supposed to be a "cone of vision" both laterally and vertically, where if you are the first vehicle at a stop line, at least one signal head for your movement should be within that range. (I am also too lazy to look up in the MUTCD what these values are at the moment.)

[jakeroot]

There is supposed to be a "cone of vision" both laterally and vertically, where if you are the first vehicle at a stop line, at least one signal head for your movement should be within that range. (I am also too lazy to look up in the MUTCD what these values are at the moment.)

Yes, I am also interested in knowing but am far too lazy to look up the numbers.

[freebrickproductions]

Here's an intersection here in Huntsville with a one signal for a driveway:
https://www.google.com/maps/@34.728219,-86.705749,3a,66.8y,270.18h,88.34t/data=!3m4!1e1!3m2!1sfqbgtlhfTVaa6FDX-SfxUg!2e0

[mrsman]

Here's one installed more recently, circa 2006: Reno, NV. Plumb Lane at Matley Lane (I-580/US 395 Southbound frontage/ramp)
https://www.google.com/maps/@39.506194,-119.780868,3a,21.4y,180.55h,91.32t/data=!3m4!1e1!3m2!1spiCDrLZaYvWGmGyAn4J4vA!2e0
(Zoom out to see the geometry and other signal heads on the approach)

This is an interesting intersection. It was formerly a tight diamond with through configuration, that had awful backups during peak hours (Plumb is a major arterial to the west, feeds into the Reno airport entrance just east of here). In 2006, NDOT & RTC converted this to a modified SPUI with through configuration, but shoehorned it in to the existing diamond footprint so as to not make any modifications to the freeway viaduct structure.

The left turns at this SPUI never go together in any direction (due to geometry and traffic volumes), so it essentially runs on a split phasing. For for the southbound direction linked here, the through movement always comes on with the left turn (the southbound right turn comes on at the same time plus overlaps with the eastbound to northbound left turn). Even still, the use three left turn heads and only one through head is baffling given that, since the at least the 1990s, it has been standard practice for new signals in Nevada to provide 2 signal heads for *every* movement regardless of what is the major movement.

It seems to me that this signal and the newer signals in the Seattle area mentioned upthread that only have one thru green, the green is always on for the same time as the left turn signal (no more and no less).  So in essence, you do get two signals, it's just that one of them is left turning.

Plus, these are all on one-way freeway ramps.  There is no cross traffic, so when you can go straight, you can go left.

So while a technical violation of MUTCD, it doesn't seem to impact safety, even if one bulb is burned out.

[jakeroot]

Another one from the Seattle-area (Tacoma). Division at North Yakima:

[roadfro]

Here's one installed more recently, circa 2006: Reno, NV. Plumb Lane at Matley Lane (I-580/US 395 Southbound frontage/ramp)
https://www.google.com/maps/@39.506194,-119.780868,3a,21.4y,180.55h,91.32t/data=!3m4!1e1!3m2!1spiCDrLZaYvWGmGyAn4J4vA!2e0
(Zoom out to see the geometry and other signal heads on the approach)
<...>
The left turns at this SPUI never go together in any direction (due to geometry and traffic volumes), so it essentially runs on a split phasing. For for the southbound direction linked here, the through movement always comes on with the left turn (the southbound right turn comes on at the same time plus overlaps with the eastbound to northbound left turn). Even still, the use three left turn heads and only one through head is baffling given that, since the at least the 1990s, it has been standard practice for new signals in Nevada to provide 2 signal heads for *every* movement regardless of what is the major movement.

It seems to me that this signal and the newer signals in the Seattle area mentioned upthread that only have one thru green, the green is always on for the same time as the left turn signal (no more and no less).  So in essence, you do get two signals, it's just that one of them is left turning.

Plus, these are all on one-way freeway ramps.  There is no cross traffic, so when you can go straight, you can go left.

So while a technical violation of MUTCD, it doesn't seem to impact safety, even if one bulb is burned out.

I can see the point with the left and through movements together. In the case I linked, the geometry is such that the first 1-2 through cars at the stop line will not be able see any of the left turn signal heads in a normal cone of vision. So that redundancy factor, if a driver knew the signal operation in order to look for it, is still lost.

[getemngo]

Another off-ramp example, this one at I-96 and East Beltline Ave. (M-37/M-44):



That doghouse signal is a thru/left signal. There is opposing traffic coming from the businesses straight ahead, but they get their own phase. Traffic going forward and left always have the green together.

Since I took this photo in 2013, the two right turn signals were replaced with "RIGHT" banners and red balls. Red arrows are rare in Michigan.

[jakeroot]

Since I took this photo in 2013, the two right turn signals were replaced with "RIGHT" banners and red balls. Red arrows are rare in Michigan.

I didn't think that was allowed anymore. Turn signals for turning movements are supposed to have red arrows, not red balls (since you could theoretically have both red and green balls lit at the same time, although in your example, it would appear that this would not happen).

[getemngo]

I didn't think that was allowed anymore. Turn signals for turning movements are supposed to have red arrows, not red balls (since you could theoretically have both red and green balls lit at the same time, although in your example, it would appear that this would not happen).

I'm not sure what the law is in Michigan, but I thought there were some states where a red right arrow is the equivalent of "NO TURN ON RED" but a right turn on a red ball is allowed? Because there's a "NO TURN ON RED" sign that lights up when opposing traffic has a green, it appears that MDOT intended to allow right turns on red, so perhaps they switched from arrows to balls to make this clearer.

I have never seen an instance in this entire state of a green light for through traffic and any red indication (ball or arrow) for right turning traffic at the same time.

It's a weird state when it comes to signals. Always has been. Since adopting the 2009 MUTCD, you have stuff like the redundant "LEFT" above a left red arrow. MDOT seems... confused.

[signalman]

Since adopting the 2009 MUTCD, you have stuff like the redundant "LEFT" above a left red arrow. MDOT seems... confused.

While I agree that it is redundant, there was no compelling reason for MDOT to remove the LEFT signage.  The sign certainly predates the all arrow display.  I don't see any reason to spend taxpayer dollars to remove the signage.  Being redundant is definitely better than the alternative.  It's also worth noting that NY and NJ often have either "Left turn signal" or "Left on green arrow only" signage on all arrow displays.  I've even seen this redundancy on newer installations in NJ that were originally installed with an all arrow display (as opposed to an original red ball that was later replaced with a red arrow).

[Kacie Jane]

I don't recall violations on any freeway intersections.

clipped

Those are all legal.  The right signal will always have the protected left, so the thru traffic by design is turning left.  (And rightfully so, since they all have dedicated right-turn bays, and traffic rarely goes straight through freeway intersections.)

According to this letter between the NCDOT and the FHWA, drivers cannot be expected to interpret which direction of movement is considered major, thus left turns are not considered through (only straight movements are through movements). Basically, each intersection is independent from one another, so despite the fact that continuing straight through any of these intersections would be a bit daft, it is legally the through movement, and should have a second through signal posted.

FWIW, the second SeaTac intersection has a shared left/straight/right lane.

edit: wrong link -- fixed

I think precisely because continuing straight through an off-ramp intersection would be a bit daft, that interpretation is a bit daft.  A motorist exiting a freeway can't be expected to recognize that continuing straight onto the on-ramp is not the major movement???



This isn't quite the right thread for this, but I didn't want to create a new thread for it.  How about 0 thru signals?

Talbot Rd (SR 515) @ I-405 NB, Renton, WA

I can't get the right angle (looks like the Google car drove northbound but not southbound), but there's two signals for the left turn onto the on-ramp (one on the mast arm, and one ground-mounted on the far side) and none for thru traffic, since there's no conflicting traffic.  I'm sure this isn't unique, but I feel like any similar intersections I've seen would at least have green up arrows.

[kj3400]

This isn't quite the right thread for this, but I didn't want to create a new thread for it.  How about 0 thru signals?

Talbot Rd (SR 515) @ I-405 NB, Renton, WA

I can't get the right angle (looks like the Google car drove northbound but not southbound), but there's two signals for the left turn onto the on-ramp (one on the mast arm, and one ground-mounted on the far side) and none for thru traffic, since there's no conflicting traffic.  I'm sure this isn't unique, but I feel like any similar intersections I've seen would at least have green up arrows.

It's really pretty common here. Here's two I found at random.

https://goo.gl/maps/3tF4t MD 122 at I-695

https://goo.gl/maps/oHfta US 1 at MD 100

[mrsman]

This isn't quite the right thread for this, but I didn't want to create a new thread for it.  How about 0 thru signals?

Talbot Rd (SR 515) @ I-405 NB, Renton, WA

I can't get the right angle (looks like the Google car drove northbound but not southbound), but there's two signals for the left turn onto the on-ramp (one on the mast arm, and one ground-mounted on the far side) and none for thru traffic, since there's no conflicting traffic.  I'm sure this isn't unique, but I feel like any similar intersections I've seen would at least have green up arrows.

It's really pretty common here. Here's two I found at random.

https://goo.gl/maps/3tF4t MD 122 at I-695

https://goo.gl/maps/oHfta US 1 at MD 100

Having green up arrows is certainly less confusing, but I don't believe it is necessary.  Plus, it will save a lot on the electricity costs for the signal.

[TEG24601]

That is quite odd, as WSDOT usually has the through signals, but perhaps since there no traffic joining the through traffic, they didn't think it was needed (i.e., no need to remind through traffic that they don't need to stop).


On second thought, there is a similar setup on SR-526 at Paine Field, except traffic is entering the expressway at that point, and formerly the next intersection when traffic was turning off.

[PColumbus73]

Here is one in Darlington, SC

https://www.google.com/maps/place/Darlington,+SC/@34.303706,-79.872058,3a,49.7y,83.14h,94.46t/data=!3m4!1e1!3m2!1sRe-w7RuhCj2yifYxzoRA-w!2e0!4m2!3m1!1s0x885569491d3bb8ed:0x4f07634fd26e39a1!6m1!1e1

[jakeroot]

Another WSDOT/City of Lakewood ball-drop. Western end of SR-512 at South Tacoma Way. Road continues into a neighborhood. Right-turn lanes are a slip lane not pictured.

https://goo.gl/n1jKVZ

[roadfro]

Here is one in Darlington, SC

https://www.google.com/maps/place/Darlington,+SC/@34.303706,-79.872058,3a,49.7y,83.14h,94.46t/data=!3m4!1e1!3m2!1sRe-w7RuhCj2yifYxzoRA-w!2e0!4m2!3m1!1s0x885569491d3bb8ed:0x4f07634fd26e39a1!6m1!1e1

Conversations in this thread are making the basic assumption that a through movement exists when commenting on the lack of a second through signal head. This example does not have a through movement...

[FreewayDan]

Found one along Marine Corps Drive in Guam (BTW, Google Street View now has Guam included):
https://www.google.com/maps/@13.485053,144.777013,3a,41.5y,177.6h,92.46t/data=!3m5!1e1!3m3!1shJZvJuER_BOPCKbsTWbzCA!2e0!3e5!6m1!1e1

[Ian]

Found one along Marine Corps Drive in Guam (BTW, Google Street View now has Guam included):
https://www.google.com/maps/@13.485053,144.777013,3a,41.5y,177.6h,92.46t/data=!3m5!1e1!3m3!1shJZvJuER_BOPCKbsTWbzCA!2e0!3e5!6m1!1e1

Huh, today I learned that Guam's traffic signals kinda look like Maryland's.

[M3019C LPS20]

I recall there was one somewhere in northern N.J. (several miles from Raritan Ctr.) several years ago. If I am not mistaken, an additional traffic signal was included since then.

[cl94]

NY 33 near the Buffalo Airport has one facing a side road. The through movement leads to a dead-end road accessing a golf course and industrial park. Each of the turn movements does get 2 signals. This setup is found elsewhere in Region 5 when a side road is opposite a little-used service road or parking lot.

[TEG24601]

Another WSDOT/City of Lakewood ball-drop. Western end of SR-512 at South Tacoma Way. Road continues into a neighborhood. Right-turn lanes are a slip lane not pictured.

https://goo.gl/n1jKVZ

To me, this doesn't count, as the flow of traffic is to the left, not straight.

[KEK Inc.]

Found one along Marine Corps Drive in Guam (BTW, Google Street View now has Guam included):
https://www.google.com/maps/@13.485053,144.777013,3a,41.5y,177.6h,92.46t/data=!3m5!1e1!3m3!1shJZvJuER_BOPCKbsTWbzCA!2e0!3e5!6m1!1e1

It seems like a lot of the Guam ones are noncompliant.   Here's one that is setup much like a Floridian span-wire signal.

https://www.google.com/maps/@13.477864,144.729939,3a,82.2y,352.96h,90.58t/data=!3m5!1e1!3m3!1sQe4OziUTYy5AI9zLf1vlWQ!2e0!3e5

It also seems like they have isolated phases.