Skip to main content

Remaining stretch of I-485 will feature three unique types of interchanges

Image
By
The remaining 5.4 miles of I-485 currently under construction in Mecklenburg County will feature three unique interchanges.  All three are in use elsewhere within the country, but would be the first ones built in the Tar Heel State.

At two of the interchanges, the new designs are considered upgrades (in traffic flow and cost savings) versus what had originally been planned.

The interchange design names are Split Diamond, Diverging Diamond, and Turbine.

Heading East from the current terminus at NC 115, the three new interchange designs run as follows:

The Split Diamond interchange will be located at Prosperity Church Road.  This interchange will consist of two access roads and six roundabouts.

Split Diamond Interchange with Prosperity Church Road (NCDOT)
The Diverging Diamond Interchange (DDI), first used in Missouri, is starting to catch interest in North Carolina.  The interchange design, actually reverses the lanes of traffic on the surface/cross street.  This will be located at the Mallard Creek Road exit on I-485.

This design replaces a planned Single Point Urban Interchange (SPUI) for 485 and Mallard Creek.


We covered a Diverging Diamond Interchange back in October when NCDOT announced it is considering the design on NC 133 where it meets the US 74/76 freeway in Leland.  These two intersections, along with two more on nearby Interstate 85 at NC 73 and Poplar Tent Road, are some of seven prospective locations for this new style of interchange.

Finally, the Turbine - an interchange that has all left turn movements circling around a central bridge in a clockwise direction, creating a seamless movement between the two highways.  This replaces the previously planned four-level stack interchange.  (Similar in design to where I-77 and 485 meet in Southern Mecklenburg County.)

The new "Turbine" interchange at 85/485.  (NCDOT)      
According to NCDOT, this type of interchange will cost less to build and maintain, take up less space, and allow for less interruptions to existing I-85 traffic during construction.


Story Links:
Last Outerbelt juntions to display unique functions ---Charlotte Observer
I-485 Charlotte Outer Loop ---NCDOT
Labels:

Comments

Froggie said…
NCDOT apparently doesn't see it as such, but I-40/Exit 195 (at NC 109) in Winston-Salem, is very much a split-diamond.
9:53 PM
Anonymous said…
Should that be counterclockwise, or am I missing something? (Maybe clockwise in countries that drive on the left...)
11:37 AM
Douglas Andrew Willinger said…
Reminds me of my Alexandria Orb proposal:

http://wwwtripwithinthebeltway.blogspot.com/2007/02/alexandria-orb-page-one-news-december.html

http://wwwtripwithinthebeltway.blogspot.com/search/label/Alexandria%20Orb
8:01 PM
Post a Comment

Popular posts from this blog

Old US Route 60/70 through Hell (Chuckwall Valley Road and Ragsdale Road)

By
Back in 2016 I explored some of the derelict roadways of the Sonoran Desert of Riverside County which were part of US Route 60/70; Chuckwalla Valley Road and Ragsdale Road. US 60 and US 70 were not part of the original run of US Routes in California.  According to USends.com US 60 was extended into California by 1932.  US 60 doesn't appear on the California State Highway Map until the 1934 edition. USends.com on US 60 endpoints 1934 State Highway Map Conversely US 70 was extended into California by 1934, it first appears on the 1936 State Highway Map. USends.com on US 70 endpoints 1936 State Highway Map When US 60 and US 70 were extended into California they both utilized what was Legislative Route Number 64 from the Arizona State Line west to Coachella Valley.  LRN 64 was part of the 1919 Third State Highway Bond Act routes.  The original definition of LRN 64 routed between Mecca in Blythe and wasn't extended to the Arizona State Line until 1931 acc...
3 comments
Read more

The last 1956-63 era California Sign State Route Spade?

By
Along southbound California State Route 170 (the Hollywood Freeway Extension) approaching the Hollywood Freeway/Ventura Freeway interchange a white California State Route 134 Sign State Route Spade can be observed on guide sign.  These white spades were specifically used during the 1956-63 era and have become increasingly rare.  This blog is intended to serve as a brief history of the Sign State Route Spade.  We also ask you as the reader, is this last 1956-63 era Sign State Route Spade or do you know of others?  Part 1; the history of the California Sign State Route Spade Prior to the Sign State Route System, the US Route System and the Auto Trails were the only highways in California signed with reassurance markers.  The creation of the US Route System by the American Association of State Highway Officials during November 1926 brought a system of standardized reassurance shields to major highways in California.  Early efforts to create a Sign State Route ...
Post a Comment
Read more

Paper Highways; Interstate H-4 through downtown Honolulu

By
The Hawaiian Island of O'ahu is home to four Interstate Highways; H-1, H-2, H-3 and H-201.  Had history gone slightly differently during the 1960s a fifth Interstate corridor on O'ahu could have been constructed through downtown Honolulu and the neighborhood of Waikiki.  The proposed corridor of Interstate H-4 can be seen above as it was presented by the Hawaii Department of Transportation during October 1968 .   This page is part of the Gribblenation O'ahu Highways page.  All Gribblenation and Roadwaywiz media related to the highway system of O'ahu can be found at the link below: https://www.gribblenation.org/p/gribblenation-oahu-highways-page.html The history of proposed Interstate H-4 The corridor of Interstate H-4 was conceived as largely following what is now Hawaii Route 92 on Nimitz Highway and Ala Moana Boulevard.   Prior to the Statehood the first signed highways within Hawaii Territory came into existence during World War II.    Dur...
Post a Comment
Read more