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Author Topic: Two Way Left Turn Lanes  (Read 2385 times)

Mapmikey

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Re: Two Way Left Turn Lanes
« Reply #25 on: February 20, 2019, 04:47:11 PM »


It's quite common to see long stretches of center turn lanes in the south in rural areas. I know SC 9 in Lancaster County has a really long one and because it's rather useless, like a lot of these really long ones are, it's often times covered in grass growing through cracks or dirt, this one had small piles (or lumps?) of dirt in the middle on unused stretches. They can also be pretty wide - I've seen some that are as wide as two, maybe two and a half lanes down here.

When South Carolina widened boulevards in suburban areas or even in some rural area starting in the 60s or so, instead of putting a grass median they would have a layer of rough pavement so that drivers could drive across it when making left turns.  This pavement area was not marked and there would be actual left turn lanes at busier locations with pavement just like the through lanes.

They converted these into the TWLTLs when that came along in the early 80s or so by paving them better and marking them.  I have not found a photo that clearly shows one but some historic aerials of the Charleston area confirm they went back a ways in time.

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jakeroot

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Re: Two Way Left Turn Lanes
« Reply #26 on: February 20, 2019, 05:06:07 PM »


It's quite common to see long stretches of center turn lanes in the south in rural areas. I know SC 9 in Lancaster County has a really long one and because it's rather useless, like a lot of these really long ones are, it's often times covered in grass growing through cracks or dirt, this one had small piles (or lumps?) of dirt in the middle on unused stretches. They can also be pretty wide - I've seen some that are as wide as two, maybe two and a half lanes down here.

When South Carolina widened boulevards in suburban areas or even in some rural area starting in the 60s or so, instead of putting a grass median they would have a layer of rough pavement so that drivers could drive across it when making left turns.  This pavement area was not marked and there would be actual left turn lanes at busier locations with pavement just like the through lanes.

They converted these into the TWLTLs when that came along in the early 80s or so by paving them better and marking them.  I have not found a photo that clearly shows one but some historic aerials of the Charleston area confirm they went back a ways in time.

When they eventually went in and marked the TWLTL's, were they pretty wide? Most roads that I can think of that would normally qualify for a grass median, usually have fairly wide medians.
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JREwing78

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Re: Two Way Left Turn Lanes
« Reply #27 on: February 20, 2019, 07:38:19 PM »

Michigan is quite fond of them, particularly in areas that were built up earlier. They will frequently convert 4-lane city streets to 3-lane streets with a TWLTL. Metro Detroit has a number of 7-lane streets (3 lanes in each direction with a TWLTL). Outside of metro Detroit, the 5-lane variety is the rule. Surface roads or streets that need three lanes each way are typically converted to boulevards with a median.

They're less common in Wisconsin; when they do appear, the TWLTL is built extra wide for later conversion to a proper median with left-turn lanes.
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Mapmikey

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Re: Two Way Left Turn Lanes
« Reply #28 on: February 20, 2019, 08:07:47 PM »


It's quite common to see long stretches of center turn lanes in the south in rural areas. I know SC 9 in Lancaster County has a really long one and because it's rather useless, like a lot of these really long ones are, it's often times covered in grass growing through cracks or dirt, this one had small piles (or lumps?) of dirt in the middle on unused stretches. They can also be pretty wide - I've seen some that are as wide as two, maybe two and a half lanes down here.

When South Carolina widened boulevards in suburban areas or even in some rural area starting in the 60s or so, instead of putting a grass median they would have a layer of rough pavement so that drivers could drive across it when making left turns.  This pavement area was not marked and there would be actual left turn lanes at busier locations with pavement just like the through lanes.

They converted these into the TWLTLs when that came along in the early 80s or so by paving them better and marking them.  I have not found a photo that clearly shows one but some historic aerials of the Charleston area confirm they went back a ways in time.

When they eventually went in and marked the TWLTL's, were they pretty wide? Most roads that I can think of that would normally qualify for a grass median, usually have fairly wide medians.

South Carolina had narrow medians on their 4-lane roads in their early days.  There are also numerous pictures of urban/suburban roads that were pretty wide but striped as 4 lanes with no median at all that later went to TWLTL...

Here is an example of a road widened in the late 1930s that had a grass median anywhere you see asphalt in the middle.  They striped the center lane a little smaller than the median presumably to give the travel lanes a bit more space:  https://goo.gl/maps/aVXX2FHJxnt

This one also in the Charleston area wasn't widened until the early 60s and AFAIK had no grass median - https://goo.gl/maps/NYsfebWZJyA2

Here is one that was widened to 4-lanes undivided in the 1940s and was recently converted to 3 lane with TWLTL - https://goo.gl/maps/7VEckTf7Q482

I'm annoyed I cannot locate an online photo of a divided road in SC with the rough paved medians that were everywhere...
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kphoger

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Re: Two Way Left Turn Lanes
« Reply #29 on: February 21, 2019, 02:40:03 PM »

I'd much rather find my gap in both directions of traffic traffic and do the turn in one motion, instead of finding a gap in traffic from the left, possibly sitting in the middle, and then merging into a gap in traffic from the right. Also, I've always experienced a bit of anxiety being the driver on the main street and not knowing if that car coming from the side street/driveway is actually turning into the TWLTL as I'd expect, or if they're erroneously turning into my lane... It's happened to me more than once.

So I don't like to put other drivers in that situation if I can avoid it. Thus, I only turn into the TWLTL when it's pretty obvious that the volume of cross traffic isn't going to allow a one-stage left turn.

FWIW, it's doesn't seem to be a super common maneuver in Nevada...

This describes my take on things as well.  I use the TWTL when I need to because of heavy traffic, and I wait for a gap in both directions otherwise.
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Thunderbyrd316

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Re: Two Way Left Turn Lanes
« Reply #30 on: June 06, 2019, 09:00:48 AM »

   This morning while cruising around GSV (via ClassyGMaps, Link: http://gokml.net/maps#ll=32.457012,245.245369&z=16&t=h ) I think I may have stumbled upon a genuine TWLTL in Mexico. It looks narrow but is marked as is common in US and Canada with the solid yellow outside lines and dashed yellow inside lines. Thoughts or opinions concerning this discovery? (Location is Calle 26 in San Luis Rio Colorado, Sonora. Google Maps Link: https://www.google.com/maps/@32.4550853,-114.7573675,3a,47.7y,212.05h,73.88t/data=!3m7!1e1!3m5!1s8CAcRheEOfNi6tfue8bT-g!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3D8CAcRheEOfNi6tfue8bT-g%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D165.24982%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656)
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webny99

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Re: Two Way Left Turn Lanes
« Reply #31 on: June 06, 2019, 10:24:41 AM »

If examples of extremely long TWLTL's are being looked for, look no further than US 30 between Lancaster and Coatesville, PA.
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Thunderbyrd316

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Re: Two Way Left Turn Lanes
« Reply #32 on: June 06, 2019, 10:05:03 PM »

   Actually Webny, if you read my OP, I had originally commented that I could not remember ever having seen one outside of the US or Canada.
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webny99

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Re: Two Way Left Turn Lanes
« Reply #33 on: June 06, 2019, 10:27:58 PM »

Oh, sorry, I didn't necessarily intend my comment to be relevant to the OP. The US 30 example just popped into my head when I saw the thread title.

I can understand why TWLTL's are not used in other countries, as they have numerous safety issues that relate to driver expectations. I would much, much rather have a proper median than a TWLTL, especially on roads with four or more lanes.

Not strictly on topic here - Another weird thing I have seen in Canada is a three lane road where passing is allowed on the side with only one lane. That strikes me as very unsafe and having the potential to get messy in a hurry.
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jakeroot

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Re: Two Way Left Turn Lanes
« Reply #34 on: June 06, 2019, 11:38:20 PM »

Not strictly on topic here - Another weird thing I have seen in Canada is a three lane road where passing is allowed on the side with only one lane. That strikes me as very unsafe and having the potential to get messy in a hurry.

Those exist in the US as well, at least out west.

Example from WA: https://goo.gl/maps/wTHi8JsYSC8bYyTU8

They're mostly relegated to rural areas, apart from bizarre situations like this.
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US 89

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Re: Two Way Left Turn Lanes
« Reply #35 on: June 07, 2019, 12:03:18 AM »

Not strictly on topic here - Another weird thing I have seen in Canada is a three lane road where passing is allowed on the side with only one lane. That strikes me as very unsafe and having the potential to get messy in a hurry.

Those exist in the US as well, at least out west.

Example from WA: https://goo.gl/maps/wTHi8JsYSC8bYyTU8

This is actually more or less the standard way to treat a passing lane in Utah, if not other states. Here's an example on US 6. From what I've observed, the double yellow is typically only used if there's a climbing lane on a road that's too curvy to allow passing anyway.
« Last Edit: June 07, 2019, 12:05:44 AM by US 89 »
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cl94

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Re: Two Way Left Turn Lanes
« Reply #36 on: June 07, 2019, 12:05:18 AM »

Not strictly on topic here - Another weird thing I have seen in Canada is a three lane road where passing is allowed on the side with only one lane. That strikes me as very unsafe and having the potential to get messy in a hurry.

Those exist in the US as well, at least out west.

Example from WA: https://goo.gl/maps/wTHi8JsYSC8bYyTU8

This is actually more or less the standard way to treat a passing lane in Utah, if not other states. Here's an example on US 6. From what I've observed, the double yellow is typically only used if there's a climbing lane on a road that's too curvy to allow passing anyway.

They even exist in webny99's native New York! See NY 28 near the Ulster/Delaware county line.
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webny99

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Re: Two Way Left Turn Lanes
« Reply #37 on: June 07, 2019, 11:23:09 AM »

They're mostly relegated to rural areas, apart from bizarre situations like this.

As much as I have expressed my distaste for TWLTL's, that should definitely be one instead of whatever the heck it is currently!  :-o
You don't often see examples where passing is allowed in both directions, much less in an area like that.

At this point, it probably isn't necessary to get into the safety concerns of this situation, as one would think they should be obvious.


They even exist in webny99's native New York! See NY 28 near the Ulster/Delaware county line.

That must be one of very few NY examples. The Canadian example I'm thinking of is on ON 15 between Kingston and Smiths Falls, but I'm have a frustrating amount of trouble finding it. Unlike the NY example, it isn't on a significant grade.
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Thunderbyrd316

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Re: Two Way Left Turn Lanes
« Reply #38 on: June 07, 2019, 11:40:23 PM »

Oh, sorry, I didn't necessarily intend my comment to be relevant to the OP. The US 30 example just popped into my head when I saw the thread title.

I can understand why TWLTL's are not used in other countries, as they have numerous safety issues that relate to driver expectations. I would much, much rather have a proper median than a TWLTL, especially on roads with four or more lanes.

Not strictly on topic here - Another weird thing I have seen in Canada is a three lane road where passing is allowed on the side with only one lane. That strikes me as very unsafe and having the potential to get messy in a hurry.

TWLTLs are quite common on 4 lane highways in Oregon and Idaho. (Not that they are uncommon in other of the 11 Western States but Oregon and Idaho seem to especially like them.)

Also, the three lanes with passing allowed by the direction with one lane thing is also somewhat common in the PNW. I can think of several places in Oregon and Washington like that.
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corco

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Re: Two Way Left Turn Lanes
« Reply #39 on: June 08, 2019, 12:00:25 AM »

That maneuver is definitely legal in Idaho, and Idaho posts signs for the one lane side that say:

Flint1979

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Re: Two Way Left Turn Lanes
« Reply #40 on: June 08, 2019, 12:03:45 AM »

There's one in Birch Run, MI. It's off WB Birch Run Road (Main Street) onto SB Beyer Road which connects to the Birch Run Outlets (the largest outlet mall in the Midwest).
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