Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[SoDakInterstateEnthusiast]

I was initially going to ask this question in the chat to get a quick answer, but I've been gone for a long while and came back only to realize that... the chat was removed. 

So, I wanted to ask if anyone knew the legitimate/technical name for these types of turn lanes https://www.google.com/maps/@43.4894079,-96.6854374,61m/data=!3m1!1e3?entry=ttu

And, to make this thread slightly more substantial: opinions on them? Do you think they're good? Bad? Pros and cons?

[kphoger]

I believe that treatment is known as "positive offset".

https://www.fhwa.dot.gov/publications/research/safety/09036/index.cfm

[SoDakInterstateEnthusiast]

I believe that treatment is known as "positive offset".

https://www.fhwa.dot.gov/publications/research/safety/09036/index.cfm

It wasn't the offset I was referring to but rather the median forcing the left-turn to go left. Does this turn lane configuration (where the mainline's left-turn is forced to turn by the median and the intersecting road's traffic cannot turn left or go straight but can go right) have a particular name, or even a moniker given by the roadgeek community?

[lordsutch]

It wasn't the offset I was referring to but rather the median forcing the left-turn to go left. Does this turn lane configuration (where the mainline's left-turn is forced to turn by the median and the intersecting road's traffic cannot turn left or go straight but can go right) have a particular name, or even a moniker given by the roadgeek community?

The generic term for directing traffic in a particular direction would be a "channelized median." The specific configuration you're referring to is most commonly referred to now as an RCUT (restricted crossing U-turn).

[SoDakInterstateEnthusiast]

It wasn't the offset I was referring to but rather the median forcing the left-turn to go left. Does this turn lane configuration (where the mainline's left-turn is forced to turn by the median and the intersecting road's traffic cannot turn left or go straight but can go right) have a particular name, or even a moniker given by the roadgeek community?

The generic term for directing traffic in a particular direction would be a "channelized median." The specific configuration you're referring to is most commonly referred to now as an RCUT (restricted crossing U-turn).

Ah. So being that the u-turn part of the intersection is not present in this example (except in the form of going to the next intersection with an open median and u-turning there), would this then be an RCLT (restricted crossing left-turn)?

[webny99]

It wasn't the offset I was referring to but rather the median forcing the left-turn to go left. Does this turn lane configuration (where the mainline's left-turn is forced to turn by the median and the intersecting road's traffic cannot turn left or go straight but can go right) have a particular name, or even a moniker given by the roadgeek community?

The generic term for directing traffic in a particular direction would be a "channelized median." The specific configuration you're referring to is most commonly referred to now as an RCUT (restricted crossing U-turn).

Ah. So being that the u-turn part of the intersection is not present in this example (except in the form of going to the next intersection with an open median and u-turning there), would this then be an RCLT (restricted crossing left-turn)?

Here's a link that might be helpful: https://safety.fhwa.dot.gov/provencountermeasures/reduced_left.cfm

I think this scenario would still be considered an RCUT as crossings are still restricted even though left turns are allowed.

[jt4]

It wasn't the offset I was referring to but rather the median forcing the left-turn to go left. Does this turn lane configuration (where the mainline's left-turn is forced to turn by the median and the intersecting road's traffic cannot turn left or go straight but can go right) have a particular name, or even a moniker given by the roadgeek community?

The generic term for directing traffic in a particular direction would be a "channelized median." The specific configuration you're referring to is most commonly referred to now as an RCUT (restricted crossing U-turn).

The example doesn't look like an RCUT to me. The median lanes are for left turns into future development, an apartment complex or subdivision has been built on the south side. Compare that to the RCUT in Fairfield, OH. The median lanes along OH-4 Bypass are marked as U-turns (with signs for Symmes Rd).
https://www.google.com/maps/@39.3440426,-84.5022494,195m/data=!3m1!1e3?entry=ttu

[froggie]

It wasn't the offset I was referring to but rather the median forcing the left-turn to go left. Does this turn lane configuration (where the mainline's left-turn is forced to turn by the median and the intersecting road's traffic cannot turn left or go straight but can go right) have a particular name, or even a moniker given by the roadgeek community?

The generic term for directing traffic in a particular direction would be a "channelized median." The specific configuration you're referring to is most commonly referred to now as an RCUT (restricted crossing U-turn).

Ah. So being that the u-turn part of the intersection is not present in this example (except in the form of going to the next intersection with an open median and u-turning there), would this then be an RCLT (restricted crossing left-turn)?

In MnDOT parlance, this would be called a "3/4 (as in three-fourths or three-quarter) intersection".

[Henry]

I like the idea of an RCLT, as it's styled the same way as an RCUT, except you can turn left onto a side street, shopping center or any other development that may be there.

[epzik8]

-Center left-turn lanes

-I like them, but some people could learn how to use them better

[kphoger]

-Center left-turn lanes

-I like them, but some people could learn how to use them better

I don't think you looked closely enough at the map.

[1995hoo]

The idea I liked was something we saw on Kauai. They didn't have the median curbing seen in the Street View image the OP linked, but what they had was a sort of median refuge area for someone turning left onto the highway (say, out of a shopping center entrance) to wait for a break in traffic. The striping was such that the refuge area was intended for one-way use only.

Here's an example outside a shopping center in Kapa'a. Notice up ahead beyond the left-turn lane. Of course, this works in Hawaii with a mellower culture in general; if they tried this in Northern Virginia, they'd probably have to put up plastic bollards to prevent people from going straight to try to use it as a passing lane (compare to this right-turn lane near where my mother lives and note the bollards to the right of the Honda CR-V, which are there to prevent people from going straight out of the right-turn only lane located behind the camera viewpoint).

[kphoger]

The idea I liked was something we saw on Kauai. They didn't have the median curbing seen in the Street View image the OP linked, but what they had was a sort of median refuge area for someone turning left onto the highway (say, out of a shopping center entrance) to wait for a break in traffic. The striping was such that the refuge area was intended for one-way use only.

Here's an example outside a shopping center in Kapa'a. Notice up ahead beyond the left-turn lane. Of course, this works in Hawaii with a mellower culture in general; if they tried this in Northern Virginia, they'd probably have to put up plastic bollards to prevent people from going straight to try to use it as a passing lane (compare to this right-turn lane near where my mother lives and note the bollards to the right of the Honda CR-V, which are there to prevent people from going straight out of the right-turn only lane located behind the camera viewpoint).

This type of setup exists in Mexico.

I think Guanajuato is especially fond of it, judging by Google Maps.
Example:  https://maps.app.goo.gl/fLd8dZRDULdvEKBq9

Here's an example in Coahuila I'm personally familiar with.
It used to have that setup.
But now it just widens to two lanes with no special markings.

And here's an example without the Bott's-dots-on-steroid treatment, in Nayarit, that I remember from my honeymoon in '06:  https://maps.app.goo.gl/4bsZvqSWcDVv8omP8

[tradephoric]

Here's a cool continuous green T-intersections in Grand Junction, CO.  Believe these are also referred to as a "Florida T" intersection:
https://www.google.com/maps?ll=39.01442,-108.47482&z=19&t=h

[CovalenceSTU]

The idea I liked was something we saw on Kauai. They didn't have the median curbing seen in the Street View image the OP linked, but what they had was a sort of median refuge area for someone turning left onto the highway (say, out of a shopping center entrance) to wait for a break in traffic. The striping was such that the refuge area was intended for one-way use only.

Here's an example outside a shopping center in Kapa'a. Notice up ahead beyond the left-turn lane. Of course, this works in Hawaii with a mellower culture in general; if they tried this in Northern Virginia, they'd probably have to put up plastic bollards to prevent people from going straight to try to use it as a passing lane (compare to this right-turn lane near where my mother lives and note the bollards to the right of the Honda CR-V, which are there to prevent people from going straight out of the right-turn only lane located behind the camera viewpoint).

California uses a similar design but with less markings, for example: https://maps.app.goo.gl/QRpp4EfGkC65bwD7A