Unique Interchange Design (Double Median U-turn)

[tradephoric]

The SR 212 (Beach Boulevard) Interchange in Jacksonville, Florida is similar to a SPUI but the median u-turn for entering freeway traffic turns it into a 2-phase signal. 


https://www.cmtengr.com/project/the-first-double-median-u-turn-intersection-in-florida/

[webny99]

I like this concept quite a bit. It also provides a relatively easy way to get off and right back on the freeway, something regular SPUI's don't typically allow for.

[epzik8]

Now the question is, how many people will be able to correctly drive through it off the bat?

[jeffandnicole]

I like this concept quite a bit. It also provides a relatively easy way to get off and right back on the freeway, something regular SPUI's don't typically allow for.

Unless there's a no U-Turn sign, it's very easy to make a u-turn at a SPUI.

[webny99]

I like this concept quite a bit. It also provides a relatively easy way to get off and right back on the freeway, something regular SPUI's don't typically allow for.

Unless there's a no U-Turn sign, it's very easy to make a u-turn at a SPUI.

True, but to clarify, I wasn't referring to U-turns. I meant going straight through to return to the freeway in the same direction.

[jeffandnicole]

I like this concept quite a bit. It also provides a relatively easy way to get off and right back on the freeway, something regular SPUI's don't typically allow for.

Unless there's a no U-Turn sign, it's very easy to make a u-turn at a SPUI.

True, but to clarify, I wasn't referring to U-turns. I meant going straight through to return to the freeway in the same direction.

Gotcha.  Although to do it here, you would need to use the right turn channel on the off-ramp, ignore that you should be continuing via the accel lane rather than stopping or yielding blocking traffic behind you, cut across 3 lanes that are generally live along with cutting over 2 solid lines, and making a u-turn. 

[roadman65]

The original SPUI in Clearwater, FL has a u turn ramp to change direction on US 19.

The SPUI on FL 50 at FL 436 has u turn ramps for SR 59 to reverse.

[ElishaGOtis]

Now the question is, how many people will be able to correctly drive through it off the bat?

Florida drivers + Jacksonville drivers + non-roadgeeks who have never seen anything like this before = uh oh 

Give it some time and a few more of these showing up and I think people will get used to it. Heck, I'm personally surprised how "well" Florida adapted to roundabouts (still not great, but better than I thought)! 

Here's something similar on I-295, though only on the NB ramp side https://maps.app.goo.gl/TtvGboMUx3u7EaVe8

[roadfro]

Here's something similar on I-295, though only on the NB ramp side https://maps.app.goo.gl/TtvGboMUx3u7EaVe8

That's a unique design for a compact space. Nicely done. 

The signal heads for the EB U-turn to freeway traffic use a red ball & green angled arrow to control the movement with NTOR signs. The red ball is also visible to the WB through traffic (SV for EB U-turn, SV for WB through). Those signal heads for the U-turn should have used red arrows or should have louvers installed.

[epzik8]

Now the question is, how many people will be able to correctly drive through it off the bat?

Florida drivers + Jacksonville drivers + non-roadgeeks who have never seen anything like this before = uh oh 

Give it some time and a few more of these showing up and I think people will get used to it. Heck, I'm personally surprised how "well" Florida adapted to roundabouts (still not great, but better than I thought)! 

Here's something similar on I-295, though only on the NB ramp side https://maps.app.goo.gl/TtvGboMUx3u7EaVe8

Nice to know.

[cwf1701]

Now the question is, how many people will be able to correctly drive through it off the bat?

I think most people from Michigan might. It looks a bit like a Michigan Left in places.

[johndoe]

Thanks for sharing.  That first location is partially on Google Street View: https://maps.app.goo.gl/5cpZEru4rffQQKHx7
Some weird signing and definitions of 'straight' or 'right turn'!  I feel like drivers wanting to make 'left onto freeway' would have to work really hard to cheat around those islands, so that's good.

That east signal on the second one is wild!  I don't remember seeing anything quite like that!  Clever way to not take any homes but I wonder how much confusion it causes.  Or why they opted for that versus a 'normal' U-turn signal (like this in Utah:https://www.google.com/maps/@40.5268717,-111.8874839,134m/data=!3m1!1e3?entry=ttu )

[webny99]

True, but to clarify, I wasn't referring to U-turns. I meant going straight through to return to the freeway in the same direction.

Gotcha.  Although to do it here, you would need to use the right turn channel on the off-ramp, ignore that you should be continuing via the accel lane rather than stopping or yielding blocking traffic behind you, cut across 3 lanes that are generally live along with cutting over 2 solid lines, and making a u-turn. 

Also true. I hadn't noticed that the right turns coming off the freeway had full acceleration lanes, but that could be problematic. That said, this does strike me as a location where proper use of the acceleration lane for its intended purpose could be quite rare (much as it is here, where >50% of traffic treats it as if there was a yield sign), so it might not interfere with normal flow as much as it looks at first glance.

[tradephoric]

Another option is to offset the free-way on-ramps.  It's technically not a SPUI anymore but the signals are all simple 2-phases. 


HWY 141 & Interstate 55 outside Saint Louis
Coordinates:  38.4421679,-90.3800497

[Henry]

I like how the engineers found a way to improve on the SPUI by adding a U-turn lane at each end for better access to the freeway entrances.

[tradephoric]

The PARCLO SPUI is another option.  It does take up a bit more ROW but it turns it into a simple 2-phase signal.

[froggie]

The PARCLO SPUI is another option.  It does take up a bit more ROW but it turns it into a simple 2-phase signal.

Theoretically, yes.  But this design introduces conflicts between right turning and opposing left turning traffic from the off-ramps.  So you would either need a 3-phase signal or right turns from the off-ramp would have to yield.

[tradephoric]

The PARCLO SPUI is another option.  It does take up a bit more ROW but it turns it into a simple 2-phase signal.

Theoretically, yes.  But this design introduces conflicts between right turning and opposing left turning traffic from the off-ramps.  So you would either need a 3-phase signal or right turns from the off-ramp would have to yield.

That's a good point i didn't think of.  Maybe yield-control would work if the traffic volumes are low enough at the interchange. 

[johndoe]

https://youtu.be/sFBBLFw0_dQ?si=JbwxcuALy9OomGBW