Unsignalized Double Left Turns

Started by MNHighwayMan, April 14, 2019, 06:05:26 AM

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jakeroot

Quote from: kphoger on January 20, 2025, 08:17:03 PM
Quote from: jakeroot on January 16, 2025, 06:16:28 PMI suppose it's worth mentioning that the lane use sign approaching the intersection matches the arrows painted on the road. No straight-through movement permitted, apparently.

Straight through onto what?  It doesn't look to me like what's on the far side of the intersection is actually a city street.  I think it's just a big driveway for the storage unit business.  The lack of a STOP sign on the far side of the intersection reinforces that for me.  And if that's the case, then there wouldn't need to be a straight-through arrow for approaching traffic.

There is a left turn from McDowell onto this road. Be it city street or not, it is clearly operating as part of the overall intersection, and not allowing straight-through movements was evidently a deliberate choice by the city since it otherwise recognizes that driveway/street.

It's not too dissimilar to this intersection in Tacoma, WA. In this case, much like the Phoenix example, the driveway is recognized by the city, as there is a painted left turn lane into the driveway. And, much like the Phoenix example, there is no designated straight lane onto the driveway from the terminating roadway. Though it does have a signal leaving the driveway.


kphoger

Quote from: jakeroot on January 21, 2025, 05:19:16 AM
Quote from: kphoger on January 20, 2025, 08:17:03 PM
Quote from: jakeroot on January 16, 2025, 06:16:28 PMI suppose it's worth mentioning that the lane use sign approaching the intersection matches the arrows painted on the road. No straight-through movement permitted, apparently.

Straight through onto what?  It doesn't look to me like what's on the far side of the intersection is actually a city street.  I think it's just a big driveway for the storage unit business.  The lack of a STOP sign on the far side of the intersection reinforces that for me.  And if that's the case, then there wouldn't need to be a straight-through arrow for approaching traffic.

There is a left turn from McDowell onto this road. Be it city street or not, it is clearly operating as part of the overall intersection, and not allowing straight-through movements was evidently a deliberate choice by the city since it otherwise recognizes that driveway/street.

It's not too dissimilar to this intersection in Tacoma, WA. In this case, much like the Phoenix example, the driveway is recognized by the city, as there is a painted left turn lane into the driveway. And, much like the Phoenix example, there is no designated straight lane onto the driveway from the terminating roadway. Though it does have a signal leaving the driveway.

Recognized by the city as existing, yes.  Left-turn lanes into private drives exist all over the place.  I see that, in the example you posted, the cross-street also lacks a straight-through arrow;  yes, I'm saying it's comparable.

For what it's worth, here's a signalized intersection more like you were expecting:  Spirit Aerosystems.

Here's an interesting one at Textron:  before with straight-through lane and green ball, after with no straight-through lane and no green ball.  And here is the removed signal.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

jakeroot

Quote from: kphoger on January 21, 2025, 01:00:36 PM
Quote from: jakeroot on January 21, 2025, 05:19:16 AM
Quote from: kphoger on January 20, 2025, 08:17:03 PM
Quote from: jakeroot on January 16, 2025, 06:16:28 PMI suppose it's worth mentioning that the lane use sign approaching the intersection matches the arrows painted on the road. No straight-through movement permitted, apparently.

Straight through onto what?  It doesn't look to me like what's on the far side of the intersection is actually a city street.  I think it's just a big driveway for the storage unit business.  The lack of a STOP sign on the far side of the intersection reinforces that for me.  And if that's the case, then there wouldn't need to be a straight-through arrow for approaching traffic.

There is a left turn from McDowell onto this road. Be it city street or not, it is clearly operating as part of the overall intersection, and not allowing straight-through movements was evidently a deliberate choice by the city since it otherwise recognizes that driveway/street.

It's not too dissimilar to this intersection in Tacoma, WA. In this case, much like the Phoenix example, the driveway is recognized by the city, as there is a painted left turn lane into the driveway. And, much like the Phoenix example, there is no designated straight lane onto the driveway from the terminating roadway. Though it does have a signal leaving the driveway.

Recognized by the city as existing, yes.  Left-turn lanes into private drives exist all over the place.  I see that, in the example you posted, the cross-street also lacks a straight-through arrow;  yes, I'm saying it's comparable.

For what it's worth, here's a signalized intersection more like you were expecting:  Spirit Aerosystems.

Here's an interesting one at Textron:  before with straight-through lane and green ball, after with no straight-through lane and no green ball.  And here is the removed signal.

So, what exactly was the point to your original reply? You said there was nothing to go straight to, except some kind of driveway. I pointed out that there is a left turn lane into the driveway, so it wasn't like the city didn't recognize the driveway as a potential exit from the intersection. And now, you [apparently] agree with me, and shared some similar examples to my additional example.

I'm not trying to be dense, I just don't get the point you were/are trying to make. There is absolutely a straight-through movement possible at the McDowell / 50th intersection, and it was seemingly intentional for the city to not allow that movement.

This might be a good example that relates to your original reply: 118 St E at WA-161, Puyallup, WA. Here, a public street ends at a major road. There are no arrows at all, so you can go whatever direction you legally can. That includes crossing over the major road into the private parking lot. Most streets, at least back home in WA, don't have arrows unless they are conveying a "you may only do this" message, or if there are multiple approach lanes. The example in Phoenix does have arrows, because there are multiple approach lanes, but there was apparently a decision not to recognize the private driveway as continuing onto that road is not recognized by the arrows on North 50th.

Along the same road to the north, a terminating road has two approach lanes, one for turning left and one for turning right. This makes sense, but there is also a driveway on the far side of the intersection. Evidently, the driveway is a legal exit from the intersection, but there isn't any actual recognition of the driveway by the local jurisdiction. No designated turn lanes into the driveway, nor does the exit from the driveway even have a stop sign.

I feel like we are getting a bit into the weeds here. Despite my otherwise aggressive tone, I do actually appreciate this tangent. It is strange how cities treat private roads. There really doesn't seem to be any standard.

kphoger

Quote from: jakeroot on January 21, 2025, 11:45:05 PMSo, what exactly was the point to your original reply? You said there was nothing to go straight to, except some kind of driveway. I pointed out that there is a left turn lane into the driveway, so it wasn't like the city didn't recognize the driveway as a potential exit from the intersection. And now, you [apparently] agree with me, and shared some similar examples to my additional example.

I'm not trying to be dense, I just don't get the point you were/are trying to make. There is absolutely a straight-through movement possible at the McDowell / 50th intersection, and it was seemingly intentional for the city to not allow that movement.

This might be a good example that relates to your original reply: 118 St E at WA-161, Puyallup, WA. Here, a public street ends at a major road. There are no arrows at all, so you can go whatever direction you legally can. That includes crossing over the major road into the private parking lot. Most streets, at least back home in WA, don't have arrows unless they are conveying a "you may only do this" message, or if there are multiple approach lanes. The example in Phoenix does have arrows, because there are multiple approach lanes, but there was apparently a decision not to recognize the private driveway as continuing onto that road is not recognized by the arrows on North 50th.

Along the same road to the north, a terminating road has two approach lanes, one for turning left and one for turning right. This makes sense, but there is also a driveway on the far side of the intersection. Evidently, the driveway is a legal exit from the intersection, but there isn't any actual recognition of the driveway by the local jurisdiction. No designated turn lanes into the driveway, nor does the exit from the driveway even have a stop sign.

I feel like we are getting a bit into the weeds here. Despite my otherwise aggressive tone, I do actually appreciate this tangent. It is strange how cities treat private roads. There really doesn't seem to be any standard.

My point was only that I don't think it necessary for a city to acknowledge a driveway with arrowheads.  Obviously cities often do.  Honestly, I hadn't thoroughly thought the idea through before posting.  And, now that I've thought about it more, I still don't know exactly where I land on that.

For what it's worth, the pavement markings in your original example are confirmed by a definitely-regulatory lane use sign just upstream.  So the prohibition against a straight-through movement is definitely what was intended.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

roadfro

Quote from: jakeroot on January 21, 2025, 05:19:16 AM
Quote from: kphoger on January 20, 2025, 08:17:03 PM
Quote from: jakeroot on January 16, 2025, 06:16:28 PMI suppose it's worth mentioning that the lane use sign approaching the intersection matches the arrows painted on the road. No straight-through movement permitted, apparently.

Straight through onto what?  It doesn't look to me like what's on the far side of the intersection is actually a city street.  I think it's just a big driveway for the storage unit business.  The lack of a STOP sign on the far side of the intersection reinforces that for me.  And if that's the case, then there wouldn't need to be a straight-through arrow for approaching traffic.

There is a left turn from McDowell onto this road. Be it city street or not, it is clearly operating as part of the overall intersection, and not allowing straight-through movements was evidently a deliberate choice by the city since it otherwise recognizes that driveway/street.

It's not too dissimilar to this intersection in Tacoma, WA. In this case, much like the Phoenix example, the driveway is recognized by the city, as there is a painted left turn lane into the driveway. And, much like the Phoenix example, there is no designated straight lane onto the driveway from the terminating roadway. Though it does have a signal leaving the driveway.
Tangent to this tangent... But can we stop to appreciate for a moment that not only does this residential driveway have its own (protected?) signal phase, but that there appears to be a signalized pedestrian crossing phase (complete with ped call buttons) to cross this driveway along a sidewalk? Never seen that before. Full setup here for this driveway...makes me wonder if there are detection loops in the driveway! :-D
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

webny99

#55
Quote from: kphoger on January 22, 2025, 09:33:48 AMFor what it's worth, the pavement markings in your original example are confirmed by a definitely-regulatory lane use sign just upstream.  So the prohibition against a straight-through movement is definitely what was intended.

I noticed that sign too, but I still don't think a prohibition of going straight is necessarily what was intended. If the city was simply choosing not to acknowledge the driveway, as you previously suggested, that logic would apply to both the pavement markings and the lane use sign. A true prohibition of what amounts to a straight through movement would typically have some sort of accompanying signage beyond just not acknowledging that the movement is possible.

kphoger

Quote from: roadfro on January 22, 2025, 12:15:31 PM...makes me wonder if there are detection loops in the driveway! :-D

I sure hope not!   :awesomeface:
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

webny99

#57
And hey, at least the city of Phoenix was thoughtful enough to bother with pavement markings and lane use signs, so drivers can at least intuit that they should be in the right lane if they do wish to go straight. This example near me has *neither* of those things, leaving it entirely up to the imagination which lane traffic going straight is supposed to use.

And the other side of this intersection brings another brain-bender: There's a widely-ignored sign prohibiting left turns, but no pavement markings or right turn only signage. So, despite the porkchop creating an awkward approach angle, there's actually nothing prohibiting you from making the "straight" movement here. I've done it myself a whole bunch of times getting between the fast food restaurants and the Webster Plaza/Ridge Park.

The whole mess needs to be revamped and signalized (especially with a new Popeye's going up next to the Taco Bell and traffic using Van Ingen Drive to get around the perpetually congested Ridge/Hard/Shoecraft intersection), but that's another subject.

plain

Newark born, Richmond bred

Big John

Quote from: roadfro on January 22, 2025, 12:15:31 PM
Quote from: jakeroot on January 21, 2025, 05:19:16 AM
Quote from: kphoger on January 20, 2025, 08:17:03 PM
Quote from: jakeroot on January 16, 2025, 06:16:28 PMI suppose it's worth mentioning that the lane use sign approaching the intersection matches the arrows painted on the road. No straight-through movement permitted, apparently.

Straight through onto what?  It doesn't look to me like what's on the far side of the intersection is actually a city street.  I think it's just a big driveway for the storage unit business.  The lack of a STOP sign on the far side of the intersection reinforces that for me.  And if that's the case, then there wouldn't need to be a straight-through arrow for approaching traffic.

There is a left turn from McDowell onto this road. Be it city street or not, it is clearly operating as part of the overall intersection, and not allowing straight-through movements was evidently a deliberate choice by the city since it otherwise recognizes that driveway/street.

It's not too dissimilar to this intersection in Tacoma, WA. In this case, much like the Phoenix example, the driveway is recognized by the city, as there is a painted left turn lane into the driveway. And, much like the Phoenix example, there is no designated straight lane onto the driveway from the terminating roadway. Though it does have a signal leaving the driveway.
Tangent to this tangent... But can we stop to appreciate for a moment that not only does this residential driveway have its own (protected?) signal phase, but that there appears to be a signalized pedestrian crossing phase (complete with ped call buttons) to cross this driveway along a sidewalk? Never seen that before. Full setup here for this driveway...makes me wonder if there are detection loops in the driveway! :-D

Cobb County GA
https://maps.app.goo.gl/8qWBxYYDdVhdSoPf7
https://maps.app.goo.gl/ipmW94U6Jm2QQN139

mrsman

Quote from: plain on January 22, 2025, 05:00:27 PM
Quote from: kphoger on January 22, 2025, 01:06:52 PM
Quote from: roadfro on January 22, 2025, 12:15:31 PM...makes me wonder if there are detection loops in the driveway! :-D

I sure hope not!   :awesomeface:

 :-D

This Tacoma intersection is really unique in that it seems like it is signalized for split-phasing with protected lefts.  I don't know how that is accomplished without some type of detection on the driveway.  (At least the examples in Cobb County are normal RYG signals on the side street, so they are activated when the opposing traffic triggers the signal.)  I guess the homeowner is out of luck if he wants to go straight or left and nobody is coming out of the shopping center, but at least he can always go right.

But the left turn from the main street into the driveway does differ from the Phoenix example.  The left turn lane is a TWTL, which is typical to access homes off a collector or arterial with a center turn lane as opposed to a dedicated left turn lane which would be used for public streets or busier driveways.  It would not be appropriate to have a dedicated left turn lane to a single family residence driveway.

 

The homeowner here [Los Angeles] gets no signal face at all, but can probably judge what cross traffic is doing by watching the ped signal.  And I bet he pushes the button so that he can leave his driveway:

https://www.google.com/maps/@34.0590514,-118.3718085,3a,75y,20.62h,92.99t/data=!3m7!1e1!3m5!1sksvdEXtt7J9N3UVD3OjHPw!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-2.9858704258237196%26panoid%3DksvdEXtt7J9N3UVD3OjHPw%26yaw%3D20.623193412805506!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDEyMi4wIKXMDSoASAFQAw%3D%3D

Growing up, I was aware of several intersections where a side street was opposite a driveway for a business.  There was a special signal with two red light aspects facing the business driveway.  Solid red (when cross street had green or yellow) or flashing red (when the opposing street had green or yellow).  I suppose traffic going straight out of a business would face a flashing red (electronic stop sign) and would have to yield to side street traffic that turns left.  Most of those that I recall have been transformed to regular RYG signals (Pico/Livonia/Bank  Sunset/Poinsettia/supermarket) but here is one off La Tijera that still maintains the unique signal phase:

La Tijera / Knowlton / shopping center:

https://www.google.com/maps/@33.9761653,-118.3732143,3a,37.5y,146.54h,81.58t/data=!3m7!1e1!3m5!1sB-B1QGb8yAltF6_LEFeYZQ!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D8.416090176993023%26panoid%3DB-B1QGb8yAltF6_LEFeYZQ%26yaw%3D146.53779012500402!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDEyMi4wIKXMDSoASAFQAw%3D%3D

-----------

I would believe that in the Phoenix example, the straight through movement is discouraged (and might be illegal).  It is probably the most difficult movement when traffic is busy to go through the entire intersection without the aid of a traffic signal.  It's certainly unique.




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