Full CFI?

[jakeroot]

Here is a cross between a PFI and a quadrant intersection in Bloomington, Indiana.  There is no commercial development on the corner parcel.
https://www.google.com/maps/@40.4883592,-88.9528379,395m/data=!3m1!1e3

Hardly a surprise. There's no way to access it on foot!

[UCFKnights]

It seems to enter the left turning lane, you have a 50% chance of getting red, then a 100% chance of red when trying to cross the main intersection, and 100% chance of red when moving back to the right side of the road. What is the time it takes if you get all 3 reds (considering 2 are guaranteed)?

Coming to a guaranteed red isn't so bad if you can turn when there are available gaps in traffic.  Unfortunately, this isn't possible at a PFI design.  That's why I think Median U-Turns are a much more elegant solution as drivers who come to a median u-turn can turn left on red at the crossover when there are available gaps.  But I think with any innovative intersection that eliminates direct left turns, people get hung up with the "relatively minor"  delays that left-turning traffic may experience, and don't focus on the improved traffic flow of the entire network.  In the video below, the driver has a 100% chance of traveling through 124 consecutive green lights, traveling over 40 miles for nearly an hour without hitting a red light.  This drive was only possible because of innovative intersections that eliminate inefficient left turn phases.   

https://www.youtube.com/watch?v=mb2R2fPB1nE

Just imagine driving through Orlando without ever hitting a red light.  Like most cities, Orlando has a bunch of conventional signals with inefficient left turn phases that kills good progression.  Which is  a shame, because many major Florida arterials would be perfect candidates for some innovative intersection designs - since many have wide medians and you have some room to play with innovative designs that redirect those inefficient lefts.  It's good to see that Florida is at least considering some innovative intersections like the PFI, even if it has its faults.

EDIT: The Michigan boulevard starts about 20 seconds into the video.  The first 20 seconds is along a conventional street with traffic signals seemingly every 200 feet apart (maybe a slight exaggeration).  Once you get to the boulevard section, the spacing of traffic signals dramatically increases.  You just don't need traffic signals servicing every strip mall, church, school, or business along a median u-turn corridor.  Having a PFI or CFI at major intersections doesn't really eliminate the need for all those "minor" signals between the major ones, thus your improvement in signal progression won't be that great with CFIs and PFIs.

My thoughts weren't that they shouldn't be considered, just that it seems the CFI seems really bad for heavy left turn traffic because they're 50% chance of getting 3 red lights and 100% chance of getting 2 red lights in a row. The PFI at least reduces that to 50% of 2 red lights and 100% of only 1 red light, so I question that the CFI really is better for heavy left turn movement.

[kphoger]

It seems to enter the left turning lane, you have a 50% chance of getting red, then a 100% chance of red when trying to cross the main intersection, and 100% chance of red when moving back to the right side of the road. What is the time it takes if you get all 3 reds (considering 2 are guaranteed)?

Coming to a guaranteed red isn't so bad if you can turn when there are available gaps in traffic.  Unfortunately, this isn't possible at a PFI design.  That's why I think Median U-Turns are a much more elegant solution as drivers who come to a median u-turn can turn left on red at the crossover when there are available gaps.  But I think with any innovative intersection that eliminates direct left turns, people get hung up with the "relatively minor"  delays that left-turning traffic may experience, and don't focus on the improved traffic flow of the entire network.  In the video below, the driver has a 100% chance of traveling through 124 consecutive green lights, traveling over 40 miles for nearly an hour without hitting a red light.  This drive was only possible because of innovative intersections that eliminate inefficient left turn phases it's in a specific place with a very specific road grid that allows for such efficient timing.   

FTFY.

[tradephoric]

My thoughts weren't that they shouldn't be considered, just that it seems the CFI seems really bad for heavy left turn traffic because they're 50% chance of getting 3 red lights and 100% chance of getting 2 red lights in a row. The PFI at least reduces that to 50% of 2 red lights and 100% of only 1 red light, so I question that the CFI really is better for heavy left turn movement.

I see your point now.  Left turning drivers potentially stop at one more traffic light at a CFI compared to a PFI.  Even if the intersection works perfectly though, the idea of having a parking lot worth of pavement to move cars through an intersection doesn't sit well.  It reminds me of the Swindon roundabout.. supposedly it works fine but just look at the pavement area required to move traffic through the intersection.  In a world where walkability is the major focus lately, the CFI and PFI and Swindon roundabout for that matter don't seem to fit in.

[kphoger]

In a world where walkability is the major focus lately, the CFI and PFI and Swindon roundabout for that matter don't seem to fit in.

I'm not sure I'd want to tackle either one by bicycle, either.  And I'm by no means a timid pedestrian or cyclist.

[US 89]

Here is a cross between a PFI and a quadrant intersection in Bloomington, Indiana.  There is no commercial development on the corner parcel.
https://www.google.com/maps/@40.4883592,-88.9528379,395m/data=!3m1!1e3

That looks like it's just a CFI. It does take up a large footprint, but it appears to be a CFI with the crossover ramps moved further away from the intersection.

[kphoger]

Here is a cross between a PFI and a quadrant intersection in Bloomington, Indiana.  There is no commercial development on the corner parcel.
https://www.google.com/maps/@40.4883592,-88.9528379,395m/data=!3m1!1e3

That looks like it's just a CFI. It does take up a large footprint, but it appears to be a CFI with the crossover ramps moved further away from the intersection.

Agreed.  Functionally equivalent to a CFI.  It's what you'd get if you blew a puff of air into a CFI.

[MCRoads]

Here is a cross between a PFI and a quadrant intersection in Bloomington, Indiana.  There is no commercial development on the corner parcel.
https://www.google.com/maps/@40.4883592,-88.9528379,395m/data=!3m1!1e3

That looks like it's just a CFI. It does take up a large footprint, but it appears to be a CFI with the crossover ramps moved further away from the intersection.

Agreed.  Functionally equivalent to a CFI.  It's what you'd get if you blew a puff of air into a CFI.

I don't think it's other. I think its just a conventional intersection with the left turn movements moved to quadrant roads. Ive seen these with straight ramps, I don't remember where, but if I showed you that, I think you would agree.

[jakeroot]

In a world where walkability is the major focus lately, the CFI and PFI and Swindon roundabout for that matter don't seem to fit in.

I'm not sure I'd want to tackle either one by bicycle, either.  And I'm by no means a timid pedestrian or cyclist.

Honestly, any "giant" complex intersection really should factor in some sort of grade separation for the pedestrian and cyclist facilities. Having those long crossing times is a burden on the flow of the intersection, and pedestrians and cyclists would prefer not to interact with cars anyway. If Florida was going to build that giant intersection on the last page, they'd be very stupid not to include some sort of underground crossing system. One that was wide and well-lit, obviously.

[Gulol]

They've opened a CFI in Colorado Springs ... [vimeo][/vimeo]

[Revive 755]

Here is a cross between a PFI and a quadrant intersection in Bloomington, Indiana.  There is no commercial development on the corner parcel.
https://www.google.com/maps/@40.4883592,-88.9528379,395m/data=!3m1!1e3

I didn't realize there had been a successful secession effort for part of Illinois  .

[Anthony_JK]

Here is a cross between a PFI and a quadrant intersection in Bloomington, Indiana.  There is no commercial development on the corner parcel.
https://www.google.com/maps/@40.4883592,-88.9528379,395m/data=!3m1!1e3

[...]

Actually, that's Bloomington/Normal, ILLINOIS (Business I-55 @ IL 9), and it's functionally a CFI, but with the turning lanes branched out. It's as if ILDOT planned an interchange at that intersection but bolted due to the development, and this was the compromise.

[20160805]

Come to think of it, "continuous flow intersection" is a bit of a misnomer considering there are still multiple sets of traffic lights. 

[johndoe]

Map of Alternative Intersections and Interchanges Across the United States:
http://go.ncsu.edu/aii

This map has DDI, RCUT, MUT, CFI, and quadrants.

[Tom958]

Come to think of it, "continuous flow intersection" is a bit of a misnomer considering there are still multiple sets of traffic lights. 

Yeah. They should be called "displaced left turn intersections". And "continuous flow intersections" should be what multilane roundabouts are called.

[jakeroot]

I'm sure the "continuous flow" name refers to the intersection's ability to process left and through traffic at the same time, even if downstream, there's some trickery that ruins the illusion.