First Median U-Turn in Florida?

[tradephoric]

Florida is getting into the Median U-Turn (MUT) game with a proposed design at Rinehart Road and County Road 46A.  I believe this would be the first MUT in Florida.  With its many wide boulevards, Florida is really an ideal state for this type of intersection design. 

http://www.i4express.com/Docs/3208-Mid-Block-fact-sheet-handout-20180307.pdf

[hotdogPi]

How do you know that none exist already?

[hbelkins]

They're thinking about installing one in Kentucky on KY 80 west of London. The language they're using here is "J-turn."

[tradephoric]

I'm not 100% sure it's the first.  It may not even be the first proposed MUT in Florida.  I modeled the Florida 56 and Bruce B Downs Blvd intersection as a MUT back in the day. 

https://www.youtube.com/watch?v=9SmSKB5d3WY

[US 89]

They're thinking about installing one in Kentucky on KY 80 west of London. The language they're using here is "J-turn."

There are a few of these in Utah, such as this one at 12300 South and State Street in Draper. UDOT's preferred name is "ThrU turn".

[formulanone]

How do you know that none exist already?

I lived there for 30 years, and I can't say I ever saw one. That doesn't mean I've been to every intersection in the state, but I could probably say I've clinched a third of their numbered route network.

Of course, many folks (myself included) performed their own "Michigan Lefts" for excessively-long traffic lights.

Will there be a NO RIGHT TURN ON RED sign for eastbound CR46A traffic? Not a fan of those in the rightmost lanes.

[BrianP]

They're thinking about installing one in Kentucky on KY 80 west of London. The language they're using here is "J-turn."

That's also the term that MDSHA uses.  But there are two versions of U-turn intersections which are covered here:
https://safety.fhwa.dot.gov/intersection/innovative/uturn/

MUT: https://www.youtube.com/watch?v=fshW_O_XggI
AKA: Michigan Left

RCUT: https://www.youtube.com/watch?v=BLwl01NCp9I
AKA: J-turn, Superstreet

[tradephoric]

Will there be a NO RIGHT TURN ON RED sign for eastbound CR46A traffic? Not a fan of those in the rightmost lanes.

The other thing to consider is will there be a NO LEFT TURN ON RED at the median crossovers.  In Michigan, drivers can turn left on red at most Median U-Turn intersections.   This greatly enhances the intersection efficiency.  The crossover lights are tied into the main signal, so if drivers are not allowed to turn left on red in gaps at the crossover lights, it almost guarantees that those drivers are going to get stopped at a red light at the main signal.  It appears the Florida MUT will restrict left turns on red at the crossovers (which unfortunately is common at MUT's outside of Michigan).  I believe the only MUT outside Michigan that allows left turns on red at the crossovers is the one at Polar Tent Road and Derita Road in Concord, North Carolina.  This MUT design is very similar to what you might see in Michigan.


https://www.google.com/maps/@35.4076232,-80.7134495,600m/data=!3m1!1e3

[tradephoric]

I believe the only MUT outside Michigan that allows left turns on red at the crossovers is the one at Polar Tent Road and Derita Road in Concord, North Carolina.  This MUT design is very similar to what you might see in Michigan.


https://www.google.com/maps/@35.4076232,-80.7134495,600m/data=!3m1!1e3

There is one main difference.  Most MUT's in Michigan don't require large loons at the crossovers because the medians are often a lot wider than what you would see in other states.  Also, the more lanes the corridor has the less need there are for loons (since the wide corridor is naturally providing the pavement space required to make the u-turn).  However, there are some examples of MUT intersections in Michigan that require loons.  Here is a recently constructed MUT in Michigan along a 4-lane boulevard with a relatively narrow median.  But when loons are required, you don't see a bunch of funky pavement markings like you do at Median U-Turns in other states.  They just keep it simple.


https://www.google.com/maps/@42.7521344,-83.2466061,454m/data=!3m1!1e3

[hbelkins]

Maryland has a bunch of these on US 301 on the Eastern Shore.

[BrianP]

Maryland has a bunch of these on US 301 on the Eastern Shore.

Though remember that the one at MD 304 was replaced with an interchange.

And there are some on US 15 north of Frederick.  Including one on the way next year:
http://www.marylandroads.com/pages/release.aspx?newsId=3153

[johndoe]

I have to wonder how many drivers just ignore the signs and make a left turn at the main intersection.  Hopefully people get used to it but it seems possible to have high crash rates.

IMO that's one big advantage the J-turn/RCUT/superstreet has: islands are placed to prevent the illegal moves.  That can't be done in MUT. 

[ilpt4u]

MUT? I thought the name for these things was "The Michigan Left"  (which, btw, made for an ackward moment or two, the first time I encountered them driving in Michigan. I got plenty of horns trying to turn Left at a normal stoplight)

Heck, we even got one or two in Southern IL now, on the East side of Marion on IL 13 (not signalized tho)

I have made my own Michigan Lefts before at intersections with a long Left Turn Line - Just go straight thru, turn around, and go right! And make sure to wave at the cars you passed, still sitting in the Left Turn Line!

[Brandon]

I have to wonder how many drivers just ignore the signs and make a left turn at the main intersection.  Hopefully people get used to it but it seems possible to have high crash rates.

IMO that's one big advantage the J-turn/RCUT/superstreet has: islands are placed to prevent the illegal moves.  That can't be done in MUT. 

Actually, crashes are reduced 30-60%.  https://wdet.org/posts/2015/10/05/81693-curiosid-where-did-the-michigan-left-come-from/

It should be implemented everywhere on divided roads like Illinois 59 or 75th Street here.

[Anthony_JK]

They're thinking about installing one in Kentucky on KY 80 west of London. The language they're using here is "J-turn."

There are a few of these in Utah, such as this one at 12300 South and State Street in Draper. UDOT's preferred name is "ThrU turn".

Louisiana has installed a ton of these intersections on major arterials, and is using this as a internim approach for US 90 between Lafayette and New Orleans until I-49 South is fully funded and completed. LADOTD also prefers the term "J-turns".

Although, the way Louisiana designs their "3-4th" intersections, through traffic and left turns on the cross streets are transferred to the J-turn movements, but left turns from the main arterial to the cross street are still allowed.

[chays]

I pass through this Florida intersection literally every day on my way to/from work.  This will definitely have an effect on my commute, and am not sure what to make of it.  Are these types of intersections generally an improvement for traffic flow?

[BrianP]

I pass through this Florida intersection literally every day on my way to/from work.  This will definitely have an effect on my commute, and am not sure what to make of it.  Are these types of intersections generally an improvement for traffic flow?

It depends on the route that you take.  If you go straight through the intersection it will be an improvement. Since the intersection would only have two signal phases which would mean more green time for straight traffic.  If you are turning left it would mean more travel distance and it's not clear how the wait time would compare since you have to go through two signals: at the U-turn (which may not be signalized in some cases, but this instance has signal controlled U-turns), and again at the intersection (which again uses the advantage of going straight through the intersection mentioned above).  Another advantage is I would guess that the green phase of the U-turn could be longer than the for left turns.  So you would be less likely to miss the green phase due to a long queue to make a U-turn than to make a left turn. 

[Brandon]

I pass through this Florida intersection literally every day on my way to/from work.  This will definitely have an effect on my commute, and am not sure what to make of it.  Are these types of intersections generally an improvement for traffic flow?

Yes.  You've taken a four-cycle signal and knocked it down to a two-cycle signal by removing the idiotic left turn phases.

[jakeroot]

I pass through this Florida intersection literally every day on my way to/from work.  This will definitely have an effect on my commute, and am not sure what to make of it.  Are these types of intersections generally an improvement for traffic flow?

It depends on the route that you take.  If you go straight through the intersection it will be an improvement. Since the intersection would only have two signal phases which would mean more green time for straight traffic.  If you are turning left it would mean more travel distance and it's not clear how the wait time would compare since you have to go through two signals: at the U-turn (which may not be signalized in some cases, but this instance has signal controlled U-turns), and again at the intersection (which again uses the advantage of going straight through the intersection mentioned above).  Another advantage is I would guess that the green phase of the U-turn could be longer than the for left turns.  So you would be less likely to miss the green phase due to a long queue to make a U-turn than to make a left turn.

Don't automatically conflate the number of signals with increased congestion. They are often timed in such a way that multiple signals can be cleared in one go.

When I build these intersections in Cities: Skylines, the U-turn movements are yield only. So the only signal is the primary crossover point. It's much easier to build a normal four-way intersection, but building any sort of crossover intersection can usually get me better traffic flow. Although the way the artificial intelligence drives, it's not worth my time at most intersections.

I pass through this Florida intersection literally every day on my way to/from work.  This will definitely have an effect on my commute, and am not sure what to make of it.  Are these types of intersections generally an improvement for traffic flow?

Yes.  You've taken a four-cycle signal and knocked it down to a two-cycle signal by removing the idiotic left turn phases.

Tucson has proved to the rest of the country that you can have very high capacity 4-way intersections. They just have to be well designed.

[hotdogPi]

Tucson has proved to the rest of the country that you can have very high capacity 4-way intersections. They just have to be well designed.

Tucson has a mile-based grid. While this is also the case for part of the Miami metro area (same state as proposed intersection, different metro area), I don't think this signal is in a grid.

[jakeroot]

Tucson has proved to the rest of the country that you can have very high capacity 4-way intersections. They just have to be well designed.

Tucson has a mile-based grid. While this is also the case for part of the Miami metro area, I don't think this signal is in a grid.

I was just trying to say that left turns don't automatically have to be an intersection's achilles heel. I'm not particularly worried about an intersection being part of a grid or not.

[tradephoric]

Are these types of intersections generally an improvement for traffic flow?

You probably won't see much benefit if they are only converting one intersection along the corridor to a Median U-turn.  Unfortunately, all the signals surrounding it will still stop both directions of travel, killing any chance of good signal progression.  So not only will you still get stopped at every other traffic light driving along Rinehart Road, you will now probably curse the fact that you can't make a direct left onto 46A. 

The benefits of Median U-turns start to shine when they are applied to an entire corridor.  People don't complain so much that they can't make a direct left at an intersection when they just drove 20, 30, even 40 miles straight without hitting a red light.   Outside of the Median U-Turn corridors of Detroit, you just don't see that type of progression.

[ilpt4u]

It should be implemented everywhere on divided roads like Illinois 59 or 75th Street here.

75th St in DuPage County and IL 59 in Will County would be perfect candidates. I think IL 59 in DuPage County would be a tight fit, tho.

Randall Rd in Kane County would be another good Suburban Area corridor to go Michigan Left

[tradephoric]

Tucson has proved to the rest of the country that you can have very high capacity 4-way intersections. They just have to be well designed.

Tucson has a mile-based grid. While this is also the case for part of the Miami metro area, I don't think this signal is in a grid.

I was just trying to say that left turns don't automatically have to be an intersection's achilles heel. I'm not particularly worried about an intersection being part of a grid or not.

In 2013 Tuscon built a few Michigan Left intersections at Oracle Road/Grant and Oracle Road/Ina. The city now has plans to build additional Michigan Lefts along Grant Road over the coming years.  When completed, Grant Road in Tuscon will be the first Median U-Turn corridor outside of Michigan. 

2 more 'Michigan lefts' due along Grant Road
http://tucson.com/news/local/govt-and-politics/more-michigan-lefts-due-along-grant-road/article_df7ed601-0a58-535e-9a14-b9caed016125.html

Phase 2 alignment/plans:
http://grantroad.info/pdf/GrantII-Exhibit-PreCon.pdf

[jakeroot]

Tucson has proved to the rest of the country that you can have very high capacity 4-way intersections. They just have to be well designed.

Tucson has a mile-based grid. While this is also the case for part of the Miami metro area, I don't think this signal is in a grid.

I was just trying to say that left turns don't automatically have to be an intersection's achilles heel. I'm not particularly worried about an intersection being part of a grid or not.

In 2013 Tuscon built a few Michigan Left intersections at Oracle Road/Grant and Oracle Road/Ina. The city now has plans to build additional Michigan Lefts along Grant Road over the coming years.  When completed, Grant Road in Tuscon will be the first Median U-Turn corridor outside of Michigan. 

2 more 'Michigan lefts' due along Grant Road
http://tucson.com/news/local/govt-and-politics/more-michigan-lefts-due-along-grant-road/article_df7ed601-0a58-535e-9a14-b9caed016125.html

Phase 2 alignment/plans:
http://grantroad.info/pdf/GrantII-Exhibit-PreCon.pdf

I went and checked out the Michigan left setup at Grant & Oracle last December, and found the overall operation to work pretty well. Cool to hear that a corridor is planned (indeed a necessity for Michigan lefts to work properly). That image from Oracle & Ina doesn't line up with the operation at Grant & Oracle, though. The U-turns were flashing yellow arrows. Hopefully the plan is for FYAs at these new U-turns and not red arrows. Michigan lefts in Michigan have the advantage of allowing left on red, and I'm certain that helps with flow.

Unless I'm mistaken, I believe the Oracle & Ina intersection is maintained by Pima County, which may explain why the overall appearance and operation is slightly different.

Here's a question: why do many Michigan Lefts outside of Michigan allow lefts from one of the arterials? Wouldn't it make better sense for timing if all traffic went through U-turn points?