AARoads Forum

Regional Boards => Ohio Valley => Topic started by: iBallasticwolf2 on June 10, 2018, 10:22:51 PM

Title: I-75/I-71 Diverging Diamond Interchanges
Post by: iBallasticwolf2 on June 10, 2018, 10:22:51 PM
Kentucky awarded $67.5 million to transform Northern Kentucky interchanges
INFRA grant funds safety, mobility improvements in Boone County
From official KYTC news release- https://transportation.ky.gov/NewsRoom/Boone%20Co%20INFRA%20Grant.pdf
Project improvements
 Replacement of the existing conventional diamond I-71/I-75 interchanges at KY 338 (Richwood
Road) and KY 536 (Mt. Zion Road) with double crossover diamond (DCD) interchanges. These
improvements eliminate bottlenecks and improve safety;
 Reconstruction of the intersection of U.S. 25 and KY 338 just east of the I-71/I-75 interchange with
KY 338 to construct a Single Point Urban Interchange (SPUI), eliminating two at-grade rail
crossings;
 Construction of northbound and southbound auxiliary lanes along I-71/I-75 north of the KY 536
interchange (MP 178.039 to MP 180.06); and
 Enhancements including minor widening along KY 536 and KY 338 to accommodate turn lanes,
intersection improvements, access management and non-motorized transportation improvements.
Construction for portions of the project will begin in 2019. The estimated completion for the entire project
is the winter of 2021.
Video showing future I-75/I-71 and KY 536 interchange

Video showing future I-75/I-71 and KY 338 interchange
Title: Re: I-75/I-71 Diverging Diamond Interchanges
Post by: qguy on June 12, 2018, 08:40:35 AM
What's with the goofy name change? Double crossover diamond interchange?
Title: Re: I-75/I-71 Diverging Diamond Interchanges
Post by: BrianP on June 12, 2018, 10:01:20 AM
I think it's a much better description of the interchange.  There are two places where the two directions of travel crossover each other.   What's diverging about it anyway?  That seems to be the nonsense description.
Title: Re: I-75/I-71 Diverging Diamond Interchanges
Post by: ilpt4u on June 12, 2018, 11:01:29 AM
The video presentation didn't give IL any credit for its DDIs...

There are at least 3 I know of in IL now
I-88 @ IL 59
I-90 @ Elmhurst Rd
I-57 @ The Hill Ave
Title: Re: I-75/I-71 Diverging Diamond Interchanges
Post by: hbelkins on June 12, 2018, 02:35:26 PM
What's with the goofy name change? Double crossover diamond interchange?

That's what Kentucky has always called them, and I agree that it's a more descriptive name than diverging diamond. What diverges from what, and where does it diverge to? It may diverge, but it "re-verges."
Title: Re: I-75/I-71 Diverging Diamond Interchanges
Post by: qguy on June 13, 2018, 10:05:55 AM
Oh I agree entirely that double-crossover is much more descriptive. I've always thought that diverging-diamond is typical "engineerspeak" created and used with no regard for public understanding. The alternate name is counter-conventional but there's nothing wrong with that when it's for a good reason and it's effective.

I can easily imagine a group of DOT officials meeting around a table saying, "If we want get a sceptical public on board with this, we'd better rename it or no one will know what in heck we're talking about."
Title: Re: I-75/I-71 Diverging Diamond Interchanges
Post by: DJStephens on July 08, 2018, 12:53:55 PM
   Any hard data on whether there is an increase in headons in these type of intersections?  It would seem that there could always be someone (usually late at night and after a few beers, or more than a few) who would drive the wrong way on one of these.   The notion of "crossing over" to the left! does seem crazy/outrageous.   
   A cheap one was installed in El Paso (Texas) on the "loop" 375 east of Ft. Bliss.  In an area where flyover connections could have been made to an intra-post connector (Spur 601) to begin with!   Plenty of room!  The loop in that area is poorly laid out, and also features a crazy shift north of that DDI.   There have been several fatalities on the loop in that area, due to the shift, and human error, not in the DDI itself. 
   There is supposedly one proposed for an East Tucson I-10 interchange (Houghton Road) and it (DDI) seems like the "cheap" way out.   And after they put in two SPUI's on I-19.  (Ajo and Valencia)  Isn't it better to keep it consistent in terms of interchange type.  As ancient interchanges are replaced.