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

Cajon Pass; Cajon Pass Toll Road, National Old Trails Road, US Route 66/91/395 and Interstate 15

By
This past weekend I spent some time in Cajon Pass traversing the many historic road alignments. Cajon Pass is located in San Bernardino County, California along the San Andreas Fault.  Cajon Pass  serves the boundary line between the Mojave Desert, the San Gabriel Mountains, San Bernardino Mountains and San Bernardino Valley.  Cajon Pass is historically one of the most traveled transportation corridors in American California and presently is served by four rail lines, Interstate 15 and California State Route 138. While Cajon Pass is known mostly for carrying US Route 66 it has carried numerous other signed highways that have had a significant impact on regional and national road travel.  While this is my best attempt to compile everything from the best sources I could find into one single transportation history blog regarding road travel in Cajon Pass I suspect as time goes on this article will be frequently updated.  If you have any information that you ...
1 comment
Read more

Pardee Dam Road

By
Pardee Dam is a 358-foot-high concrete structure located near Campo Seco at the Calaveras County and Amador County Line.  Pardee Dam impounds the Mokelumne River which forms the namesake Pardee Reservoir.  Pardee Dam was completed during 1929 and is part of the East Bay Municipal Utility District.  Pardee Dam is accessed by the namesake Pardee Dam Road which crosses the structure via the one-lane road seen as the blog cover photo.   Part 1; the history of Pardee Dam Road The closest community to Pardee Dam is that of Campo Seco on the Calaveras County side of the Mokelumne River.  Campo Seco was founded in 1850 by Mexican Miners who worked placer claims in Oregon Gulch during the height of the California Gold Rush.  Campo Seco would reach a population of about three hundred by 1860 spurred by the numerous mining claims in the area.  Main Street of Campo Seco flowed directly into the Campo Seco Turnpike which had been authorized by the California L...
2 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