Stangest Traffic Lights

[CardInLex]

Four t-shaped straight-ahead signals in Lexington, KY, with two red balls each:
https://www.google.pl/maps/@37.9948992,-84.5221116,3a,27.3y,23.85h,97.26t/data=!3m6!1e1!3m4!1sEDtg2yx8wR7aw91ZSRWdOQ!2e0!7i16384!8i8192

The pairs of balls are even more visible from a side street:
https://www.google.pl/maps/@37.9947564,-84.5219337,3a,26.2y,348.79h,92.06t/data=!3m6!1e1!3m4!1sI6cesr6Pp67idulcwvSvig!2e0!7i16384!8i8192

Another one across KY-4, with a standard left turn signal, right before a variable-lane config on US-27:
https://www.google.pl/maps/@37.9975729,-84.5214192,3a,28.8y,19.16h,90.09t/data=!3m6!1e1!3m4!1s6WpqQ8pCQ-LynPvXAOy_wA!2e0!7i16384!8i8192

LFUCG (which maintains all signals in Fayette County, even on state routes) uses the double red configuration at intersections that have a high number of red-light runners.

[mrsman]

Also, does anyone have a clue about this a bit further north? I think it has to do with the variable-lanes configuration.

Yeah, that's the last left turn signal before the lanes change back to non reversible. The reversible lanes in the street view are in their "non-rush hour"  configuration.

I wonder if you can tell us more about this operation of the signals.  It seems interesting.  5 signal heads in each direction, two regular, two 4 aspect, and the left most is protected only.  Are left turns here usually protective/permissive except during the rush hour?  Do the 4 aspect signals serve as FYAs when they service left turn lanes and then act as RYG signals when serving a straight lane?

It is rare for any reversible operation to provide left turn priority, as it can get complicated.  It seems that there is a left turn lane provided at all times: 2-L-4, 3-L-3, 4-L-2.  It is rare as it is more common to see: 3-4, 3-L-3, 4-3 with left turns prohibited during rush hours.

[CardInLex]

Also, does anyone have a clue about this a bit further north? I think it has to do with the variable-lanes configuration.

Yeah, that's the last left turn signal before the lanes change back to non reversible. The reversible lanes in the street view are in their "non-rush hour"  configuration.

I wonder if you can tell us more about this operation of the signals.  It seems interesting.  5 signal heads in each direction, two regular, two 4 aspect, and the left most is protected only.  Are left turns here usually protective/permissive except during the rush hour?  Do the 4 aspect signals serve as FYAs when they service left turn lanes and then act as RYG signals when serving a straight lane?

It is rare for any reversible operation to provide left turn priority, as it can get complicated.  It seems that there is a left turn lane provided at all times: 2-L-4, 3-L-3, 4-L-2.  It is rare as it is more common to see: 3-4, 3-L-3, 4-3 with left turns prohibited during rush hours.

Left turns along this stretch are always protected. One lane is always dedicated to be a left turn lane. The four section heads are R-Y-G-GA. The green arrow is only used when the lane is assigned as a left turn lane (the green orb is not illuminated during this time). The whole set up may not be MUTCD compliant because there are always dark/unilluminated signal heads.

Farther down Nicholasville Rd/US 27 the lanes go to 1-L-4 (every lane line is a broken double yellow). This configuration makes the dual left turns from side streets variable as well (look at Alumni Drive intersection). That means the left left turn lane sometimes turns to the second lane and sometimes turns to the right lane of US 27.
https://goo.gl/maps/kYjtDgCUUZhtaXaS9

The configuration works well except if you have the unfortunate need to head downtown in afternoon rush hour which can take 40 minutes to an hour just to go a few miles with just one lane.

Louisville has a similar configuration for Baxter Ave/Bardstown Rd (US 31E/US 150). Normal configuration: P-1-1-P; Rush Hour: 2-L-1. https://goo.gl/maps/PAAkJhToWg5sYCdQ6

[mrsman]

Also, does anyone have a clue about this a bit further north? I think it has to do with the variable-lanes configuration.

Yeah, that's the last left turn signal before the lanes change back to non reversible. The reversible lanes in the street view are in their "non-rush hour"  configuration.

I wonder if you can tell us more about this operation of the signals.  It seems interesting.  5 signal heads in each direction, two regular, two 4 aspect, and the left most is protected only.  Are left turns here usually protective/permissive except during the rush hour?  Do the 4 aspect signals serve as FYAs when they service left turn lanes and then act as RYG signals when serving a straight lane?

It is rare for any reversible operation to provide left turn priority, as it can get complicated.  It seems that there is a left turn lane provided at all times: 2-L-4, 3-L-3, 4-L-2.  It is rare as it is more common to see: 3-4, 3-L-3, 4-3 with left turns prohibited during rush hours.

Left turns along this stretch are always protected. One lane is always dedicated to be a left turn lane. The four section heads are R-Y-G-GA. The green arrow is only used when the lane is assigned as a left turn lane (the green orb is not illuminated during this time). The whole set up may not be MUTCD compliant because there are always dark/unilluminated signal heads.

It certainly isn't compliant, although they may have quallified for a special exemption given the unique usage.  Another problem is the use of a R-Y-G-GA signal for a protected only left.  Under the current MUTCD, a left turn signal is supposed to have red and yellow arrows, not orbs.  And to the extent that orbs are used, a sign like "left turn signal" (so common in PA and VA) should be used to identify the signal as controlling left turns.  And as you correctly noted dark signals are an issue, but probably not a violation because there are other signals lit that show the same aspect.

If I were to assign signals to something like this, I would replace the 4 aspect signals with 6 aspect signals (hung like a doghouse, but with 6 aspects).  The 6 aspect signals would be:

RA - R
YA - Y
GA - G

These would clearly dictate the traffic of the lane in question and only the relevant movement would be lit up.

Does KY require at least two signal faces for the left turn movement?  (Some states don't.)  That may also be a violation if only one left turn arrow is lit up at a time based on lane configuration.  An easy fix for that would be a pole mounted signal on the far left corner.

[CardInLex]

Also, does anyone have a clue about this a bit further north? I think it has to do with the variable-lanes configuration.

Yeah, that's the last left turn signal before the lanes change back to non reversible. The reversible lanes in the street view are in their "non-rush hour"  configuration.

I wonder if you can tell us more about this operation of the signals.  It seems interesting.  5 signal heads in each direction, two regular, two 4 aspect, and the left most is protected only.  Are left turns here usually protective/permissive except during the rush hour?  Do the 4 aspect signals serve as FYAs when they service left turn lanes and then act as RYG signals when serving a straight lane?

It is rare for any reversible operation to provide left turn priority, as it can get complicated.  It seems that there is a left turn lane provided at all times: 2-L-4, 3-L-3, 4-L-2.  It is rare as it is more common to see: 3-4, 3-L-3, 4-3 with left turns prohibited during rush hours.

Left turns along this stretch are always protected. One lane is always dedicated to be a left turn lane. The four section heads are R-Y-G-GA. The green arrow is only used when the lane is assigned as a left turn lane (the green orb is not illuminated during this time). The whole set up may not be MUTCD compliant because there are always dark/unilluminated signal heads.

It certainly isn't compliant, although they may have quallified for a special exemption given the unique usage.  Another problem is the use of a R-Y-G-GA signal for a protected only left.  Under the current MUTCD, a left turn signal is supposed to have red and yellow arrows, not orbs.  And to the extent that orbs are used, a sign like "left turn signal" (so common in PA and VA) should be used to identify the signal as controlling left turns.  And as you correctly noted dark signals are an issue, but probably not a violation because there are other signals lit that show the same aspect.

If I were to assign signals to something like this, I would replace the 4 aspect signals with 6 aspect signals (hung like a doghouse, but with 6 aspects).  The 6 aspect signals would be:

RA - R
YA - Y
GA - G

These would clearly dictate the traffic of the lane in question and only the relevant movement would be lit up.

Does KY require at least two signal faces for the left turn movement?  (Some states don't.)  That may also be a violation if only one left turn arrow is lit up at a time based on lane configuration.  An easy fix for that would be a pole mounted signal on the far left corner.

I would like that signal configuration.

The ends of the reversible lanes feature blank out "LANE ENDS MERGE RIGHT"  to get traffic back into the proper lanes.

The switchover takes approximately 15 minutes and starts at one end and cascades to the other end. There is a few minute time frame where the reversible lanes just feature X's to get any stragglers out of the lanes.

The reversible configuration also is used for events at Kroger Field.

No, KY does not use two signal heads for left turns (except if it is a single lane approach where you have to turn left).

[mrsman]

Also, does anyone have a clue about this a bit further north? I think it has to do with the variable-lanes configuration.

Yeah, that's the last left turn signal before the lanes change back to non reversible. The reversible lanes in the street view are in their "non-rush hour"  configuration.

I wonder if you can tell us more about this operation of the signals.  It seems interesting.  5 signal heads in each direction, two regular, two 4 aspect, and the left most is protected only.  Are left turns here usually protective/permissive except during the rush hour?  Do the 4 aspect signals serve as FYAs when they service left turn lanes and then act as RYG signals when serving a straight lane?

It is rare for any reversible operation to provide left turn priority, as it can get complicated.  It seems that there is a left turn lane provided at all times: 2-L-4, 3-L-3, 4-L-2.  It is rare as it is more common to see: 3-4, 3-L-3, 4-3 with left turns prohibited during rush hours.

Left turns along this stretch are always protected. One lane is always dedicated to be a left turn lane. The four section heads are R-Y-G-GA. The green arrow is only used when the lane is assigned as a left turn lane (the green orb is not illuminated during this time). The whole set up may not be MUTCD compliant because there are always dark/unilluminated signal heads.

It certainly isn't compliant, although they may have quallified for a special exemption given the unique usage.  Another problem is the use of a R-Y-G-GA signal for a protected only left.  Under the current MUTCD, a left turn signal is supposed to have red and yellow arrows, not orbs.  And to the extent that orbs are used, a sign like "left turn signal" (so common in PA and VA) should be used to identify the signal as controlling left turns.  And as you correctly noted dark signals are an issue, but probably not a violation because there are other signals lit that show the same aspect.

If I were to assign signals to something like this, I would replace the 4 aspect signals with 6 aspect signals (hung like a doghouse, but with 6 aspects).  The 6 aspect signals would be:

RA - R
YA - Y
GA - G

These would clearly dictate the traffic of the lane in question and only the relevant movement would be lit up.

Does KY require at least two signal faces for the left turn movement?  (Some states don't.)  That may also be a violation if only one left turn arrow is lit up at a time based on lane configuration.  An easy fix for that would be a pole mounted signal on the far left corner.

I would like that signal configuration.

The ends of the reversible lanes feature blank out "LANE ENDS MERGE RIGHT"  to get traffic back into the proper lanes.

The switchover takes approximately 15 minutes and starts at one end and cascades to the other end. There is a few minute time frame where the reversible lanes just feature X's to get any stragglers out of the lanes.

The reversible configuration also is used for events at Kroger Field.

No, KY does not use two signal heads for left turns (except if it is a single lane approach where you have to turn left).

It's interesting that you have a cascading switchover on a surface street, but it is probably necessary given the complicated traffic pattern here.  There are some reversible lanes in my area, where the changeover is much more dramatic.  Of course, during peak times, there are no dedicated left turn lanes and any center left turn lane that existst during off-peak hours just becomes a thru traffic lane in the dominant direction during peak.

For those familiar with Silver Spring and DC, the most prominent reversibles are Connecticut Ave: 3-3 off peak, 2-4 peak (parking allowed during off-peak so its really 2-2); Georgia Ave near the Beltway 3-L-3 converting to 3-4 during peak with left turns prohibited on the stretch during peak hours; and Colesville Road with a similar configuration to Connecticut Ave.  For both Connecticut and Colesville left turns are generally allowed at most intersections, but a left turn will generally block a thru traffic lane.  There are also signs that dictate the times for the reversible lanes, so people have to move back to the regular lanes when rush hour ends.

The old rule in many states requiring two signal faces is likely due to the concern of a bulb burning out.  With LED technology, this is no longer the same level of concern and I can see an accommodation for a one signal per lane arrangement where if there is only one left turn lane, only one left turn signal face is needed.  If the LED lights are in an array, you need many "bulbs" to burn out before you have a dark signal.

[SignBridge]

I have seen a number of LED signals not working. They may not burn out like incandescent bulbs do, but they are subject to malfunctions. Like seeing half of the cluster in one light not working or an entire light flickering very rapidly.

So we still need the redundancy of at least two heads in every direction for both reliability and conspicuity.

[CJResotko]

Here's an oddball setup that used to exist in Lansing, Michigan.

https://youtu.be/zIqTYPFPqp4

At the northbound approach of the intersection, there was a standard RYG signal, a singular red section, and a blank-out sign. There's a stop sign at that approach, so the RYG signal flashed red.

[JKRhodes]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

[jakeroot]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

[JKRhodes]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

Eastbound Broadway to Westbound Maclovio is restricted. I suppose the rationale is that anyone coming east on Broadway would have already turned onto 6th Ave or Stone Ave to get to the point  it serves. Though 4th Ave traffic south of broadway is still relegated to using Toole or the other section of 4th to get through thanks to that decision. 

[jakeroot]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

Eastbound Broadway to Westbound Maclovio is restricted. I suppose the rationale is that anyone coming east on Broadway would have already turned onto 6th Ave or Stone Ave to get to the point  it serves. Though 4th Ave traffic south of broadway is still relegated to using Toole or the other section of 4th to get through thanks to that decision.

That actually reminds me, can someone turn right from northbound 4th directly into the slip lane to continue on Congress? Or would someone have to divert over to 5th?

[JKRhodes]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

Eastbound Broadway to Westbound Maclovio is restricted. I suppose the rationale is that anyone coming east on Broadway would have already turned onto 6th Ave or Stone Ave to get to the point  it serves. Though 4th Ave traffic south of broadway is still relegated to using Toole or the other section of 4th to get through thanks to that decision.

That actually reminds me, can someone turn right from northbound 4th directly into the slip lane to continue on Congress? Or would someone have to divert over to 5th?

Technically they would have to divert to Herbert or 5th. Google Maps doesn't allow the move. In practice it's probably done all the time though, despite the "no straight" sign, there seems to be a great deal of black tire residue on the gore striping:

https://goo.gl/maps/r9D4kkcmXZak9itf6

Another option is 12th St to Toole, taking the bridge over Broadway to the other side of Congress.

[US 89]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

This design with the giant overhead tube is almost identical to one in Utah at SR 201 and 7200 West. I've never seen another like it before.

[jeffandnicole]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

At least for the one direction, due to the curve near the intersection the far side overheads can't be seen when the left turn channel starts, so I get the reasonong for the near side lights there. Guess they just copied the design for the opposing direction for uniformity. 

Tube gantry appears to be 145 feet long or so.  A mast arm would've been about 70 - 75 feet to contain the signals as placed here. At that point, the cost to properly build 2 masts is probably close to the cost of a single monotube

[JKRhodes]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

This design with the giant overhead tube is almost identical to one in Utah at SR 201 and 7200 West. I've never seen another like it before.

Phoenix has a ton of tube gantries on Grand Ave at the major 6-way intersections like this one
https://maps.app.goo.gl/8AgwkUenfmFB5xUm7?g_st=ic

Also a few in the Queen Creek/San tan valley area for some odd reason (perfectly square 4-way intersections
https://maps.app.goo.gl/2fwWMpiVtjaX9TFV7?g_st=ic

[SignBridge]

https://maps.app.goo.gl/T1pTbT99MFcuhfwu7?g_st=ic

Maclovio Barraza Parkway in Tucson recently opened to traffic west of Broadway.

Functionally they are quite normal. But I'm intrigued by decision to utilize mixture of tube gantry, near side mast arms and far side mast arms. Seems overkill. That said, Layout is weird; original plans for full SPUI were long scrapped, finally revived and scaled waaaay back, with narrow 4 lane road tied into set of half SPUI ramps.

Thank you for sharing this, I was waiting for GSV to pop up for this intersection.

It is indeed quite odd. I'm surprised that the tube gantry was actually replaced with a new one. You'd think they'd either keep the original, or replace it with a more typical mast arm setup for all approaches.

Unusually for Tucson (and Arizona in general), no left turn supplemental signal is present for the westbound left turn onto southbound Aviation.

This design with the giant overhead tube is almost identical to one in Utah at SR 201 and 7200 West. I've never seen another like it before.

Phoenix has a ton of tube gantries on Grand Ave at the major 6-way intersections like this one
https://maps.app.goo.gl/8AgwkUenfmFB5xUm7?g_st=ic

Also a few in the Queen Creek/San tan valley area for some odd reason (perfectly square 4-way intersections
https://maps.app.goo.gl/2fwWMpiVtjaX9TFV7?g_st=ic

So the latest state-of-the-art is we're back to diagonal spans? I guess they're good at very wide intersections where there is reasonable distance from the stop line to the signal-heads.

[zachary_amaryllis]

I can't get GSV to stay there, but some of the lights on Lower Wacker in Chicago look weird, as far as the angles go.

[andrepoiy]

Here's one that's strange:

A "U-turn signal" sign, with a "No left turn" sign. However, the signal has a left arrow and the road markings (not shown in the screenshot) also indicate a left turn.



link: https://goo.gl/maps/ceLQdvaMfctChnPe6

[SignBridge]

Here's one that's strange:

A "U-turn signal" sign, with a "No left turn" sign. However, the signal has a left arrow and the road markings (not shown in the screenshot) also indicate a left turn.



link: https://goo.gl/maps/ceLQdvaMfctChnPe6

This is in Canada I assume?

[Big John]

^^ The U-turn signal was introduced to the American MUTCD in 2009 and the left-turn arrow was used to represent the U-turn before then, and still is to be used to represent a shared left and U turn.  I don't think (correct me if I'm wrong) any Canadian province adopted the U-turn signal.

[Revive 755]

^^ The U-turn signal was introduced to the American MUTCD in 2009 and the left-turn arrow was used to represent the U-turn before then, and still is to be used to represent a shared left and U turn.  I don't think (correct me if I'm wrong) any Canadian province adopted the U-turn signal.

I'm not seeing a specific U-Turn signal sign in the national edition of the 2009 American MUTCD.  I do see one in Figure 2B-27 Sheet 1 of 2 in the figures previously released for the draft of the next American MUTCD edition (R10-10a).

[roadfro]

^^ The U-turn signal was introduced to the American MUTCD in 2009 and the left-turn arrow was used to represent the U-turn before then, and still is to be used to represent a shared left and U turn.  I don't think (correct me if I'm wrong) any Canadian province adopted the U-turn signal.

I'm not seeing a specific U-Turn signal sign in the national edition of the 2009 American MUTCD.  I do see one in Figure 2B-27 Sheet 1 of 2 in the figures previously released for the draft of the next American MUTCD edition (R10-10a).

The U-turn signal head (with U-turn arrows instead of left arrow) was introduced in the 2009 MUTCD. There was no accompanying sign introduced at the time (although the few uses I've seen have a U-turn lane assignment sign adjacent to the signal head).

[jakeroot]

I can think of numerous variants of U-turn regulatory signs, I am surprised they are not in the MUTCD.

U-turn "ONLY" sign: https://goo.gl/maps/rHJmpW4pohDnqAUm6
U-turn "OK" sign: https://goo.gl/maps/7W1Q1ZY8dPYhZFEk6
U-turn with left arrow: https://goo.gl/maps/p4qhkBMjCm9KRjoz9
U-turn with double left arrow: https://goo.gl/maps/BTtUhz9b1DUyBFuj7

The last sign is virtually identical to a lane-assignment sign very common in California, where it has been in use for decades.

[GaryA]

I can think of numerous variants of U-turn regulatory signs, I am surprised they are not in the MUTCD.

U-turn "ONLY" sign: https://goo.gl/maps/rHJmpW4pohDnqAUm6
U-turn "OK" sign: https://goo.gl/maps/7W1Q1ZY8dPYhZFEk6
U-turn with left arrow: https://goo.gl/maps/p4qhkBMjCm9KRjoz9
U-turn with double left arrow: https://goo.gl/maps/BTtUhz9b1DUyBFuj7

The last sign is virtually identical to a lane-assignment sign very common in California, where it has been in use for decades.

One more variation - Left lane must U-turn: https://goo.gl/maps/rUNmgRVc6qyr7ESF6