Partial CFI for I 35 and MO 152 Interchange + Kansas Street Improvements

[UAN51]

I've never seen this type of interchange built before, but MoDOT is proposing a partial CFI for the super congested I 35 and MO 152 interchange at Liberty, MO. Initially, I thought MoDOT would build a DDI when they first announced this project but this partial CFI is the final choice. The project (including Kansas St. improvements to the east) will be out for bid in Fall 2018 and construction is from 2019 to end of 2020/start of 2021.

Diagram for the project is here: http://www.modot.org/kansascity/major_projects/documents/011918_Route152_Over_I-35_Project.pdf

Full website of the project is here: http://www.modot.org/kansascity/major_projects/Route_152_Kansas_Street.htm

What are your thoughts? Have you seen this type of interchange before? If so, where?

[kphoger]

I've never seen this design before either.  DDI, yes.  CFI, yes.  But this hybrid thing, no.

My thoughts?  Hellz to the yeah!  This interchange is along one of my two preferred routes from here to Iowa or Minnesota.  (KTA → I-435 → MO-152 → I-35)  As annoying as the stoplights are to the west of this interchange, I always dread having to wait for the two existing stoplights at the interchange itself.  This design removes one of them.  It also appears that the remaining stoplight will be basically two phases with a lagging left, meaning the overall wait for it to turn green might also be reduced as well.  I'm pretty happy with this.

[rte66man]

I've never seen this design before either.  DDI, yes.  CFI, yes.  But this hybrid thing, no.

My thoughts?  Hellz to the yeah!  This interchange is along one of my two preferred routes from here to Iowa or Minnesota.  (KTA → I-435 → MO-152 → I-35)  As annoying as the stoplights are to the west of this interchange, I always dread having to wait for the two existing stoplights at the interchange itself.  This design removes one of them.  It also appears that the remaining stoplight will be basically two phases with a lagging left, meaning the overall wait for it to turn green might also be reduced as well.  I'm pretty happy with this.

But 35 from the 29/35 split north to the US69 Excelsior Springs exit still sucks.  50's design that hasn't been update or widened.  They screwed up the rebuild at Pleasant Valley road by not building wider bridges to accommodate any future widening.

They also screwed up 152 west because they let all that development encroach on the existing road.  They always had making 152 into a freeway west of there.  Surely they could have preserved the RoW east to 35.

[J N Winkler]

I don't care for this design at all.  I predict it will be difficult to sign and will still confuse motorists even with optimum signing.  Southbound to eastbound traffic has to swoop across two lanes within a very short distance in order to avoid an unwanted U-turn onto northbound I-35, so there are likely to be operational problems from this as well.

I will be happy to download the plans for this job because MoDOT's signing plans are slick, even when they are BS.  It won't make I-35 through Liberty any less purgatorial, and I am already at the point where I have to make comfort/gas stops beyond Kearney if I want to be assured of easy exit from and easy return to I-35.

[Revive 755]

I don't care for this design at all.  I predict it will be difficult to sign and will still confuse motorists even with optimum signing.  Southbound to eastbound traffic has to swoop across two lanes within a very short distance in order to avoid an unwanted U-turn onto northbound I-35, so there are likely to be operational problems from this as well.

Per this video and this video the SB I-35 to EB MO 152 movement is signalized, so the lane change should not be an issue.  I think wrong way drivers might be a bigger issue.

I hope this interchange does get built and MoDOT does a good job collecting data on it so if the design does work it can be considered elsewhere.

[J N Winkler]

Per this video and this video the SB I-35 to EB MO 152 movement is signalized, so the lane change should not be an issue.  I think wrong way drivers might be a bigger issue.

I take your point about it being signalized, and I am also aware that since Missouri is one of very few US states without a turn-to-nearest-lane law (California and Texas being two of the others), drivers exiting southbound I-35 can simply turn directly into the straight-ahead lane for eastbound SR 152.  However, Kansas City is a border metropolis and Kansas does have a turn-to-nearest-lane law, so I can see problems arising from motorists thinking they need to turn into the further left of the two left-turn lanes and then signal a lane change across two lanes to avoid the unwanted left turn.

I hope this interchange does get built and MoDOT does a good job collecting data on it so if the design does work it can be considered elsewhere.

Data collection is also good for excluding designs that turn out not to perform as well in real life as they do on paper or in modelling software.  I note that despite experimentation with CFIs in Utah, North Carolina, and Minnesota, they have not caught on to nearly the same degree as DDIs and roundabouts.

[pianocello]

What are the benefits to this design over a conventional DDI? I doubt a DDI at this location would require 11 lanes of bridge, and I think the eastern intersection with this design would require 3 phases (one for each movement going toward the EB lanes).

The only thing I can think of is that this design might allow the agencies more freedom to tweak the signal timing to benefit the EB-NB movement, but I'm not sure.

[mvak36]

If they do end up going with this design, one problem I see is that they will have to do is make sure the right lane on the crossover bridge (SB 35 to EB 152 movement) doesn't have too much of a queue. Otherwise it has the potential to block the EB 152 traffic wanting to go north on 35.

The few times I have been at that interchange, it does look like most of the traffic is on 35 NB waiting to turn left onto WB 152, so maybe that's why they did this design.

What are the benefits to this design over a conventional DDI? I doubt a DDI at this location would require 11 lanes of bridge, and I think the eastern intersection with this design would require 3 phases (one for each movement going toward the EB lanes).

The only thing I can think of is that this design might allow the agencies more freedom to tweak the signal timing to benefit the EB-NB movement, but I'm not sure.

I don't think a DDI would work that well here. There is a lot of through traffic on MO 152 at this intersection. As I understand it, A DDI is preferable when there is a high volume of left turns.

[theroadwayone]

My quick thoughts are let them do it. Whether it succeeds or fails is up to them. If it works, it can be used as a blueprint to other similar problems elsewhere. If not, let them tweak it so that it works, and then incorporate the lessons into similar designs.

[CadmanTD]

Forgive my bumping an old topic, but I'm new and this project is ongoing. Construction work seems to be moving at a good pace and the delays are not much worse than the everyday delays before construction.

However It seems to me that a better fix for this area would have included adding an extra lane to I-35 from Kearney to the 435 junction. I remember seeing the simulation when MoDot released it and wondering why it showed so few cars traveling up and down I-35. Not shown on the simulation is the stop and go backup just getting to the exit.  Will this area ever be expanded to 3 lanes?

[Revive 755]

However It seems to me that a better fix for this area would have included adding an extra lane to I-35 from Kearney to the 435 junction. I remember seeing the simulation when MoDot released it and wondering why it showed so few cars traveling up and down I-35. Not shown on the simulation is the stop and go backup just getting to the exit.  Will this area ever be expanded to 3 lanes?

It's probably on MoDOT's unfunded wish list already, behind US 40 from Route K to I-70 in the St. Louis area and many segments of I-44 and I-70.