Skip to main content

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

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

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.
Anonymous said…
Should that be counterclockwise, or am I missing something? (Maybe clockwise in countries that drive on the left...)
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

Popular posts from this blog

The Pollasky Bridge

The Pollasky Bridge near modern day Friant is a ruined highway bridge which was completed during early 1906 as part of the Fresno-Fresno Flats Road.  The structure is one of the oldest known arch concrete spans to have been constructed in California.  The bridge briefly carried California State Route 41 following the destruction of the Lanes Bridge in 1940.  The Pollasky Bridge itself was destroyed by flooding during 1951, but the ruins can still be found on the Madera County side of the San Joaquin River.   Pictured as the blog cover is the Pollasky Bridge as it was featured in the 1913 book "The Concrete Bridge."  The structure can be seen crossing the San Joaquin River near Friant below on the 1922 United States Geological Survey Map.   Part 1; the history of the Pollasky Bridge The Pollasky Bridge site is near modern day Friant of Fresno County.  The community of Friant was established as Converse Ferry during 1852 on the San Joaquin Rive...

Trimmer Springs Road (Fresno County)

Trimmer Springs Road is an approximately forty-mile rural highway located in Fresno County.  The corridor begins near in California State Route 180 in Centerville and extends to Blackrock Road at the Kings River in the Sierra Nevada range near the Pacific Gas & Electric Company town of Balch Camp. The roadway is named after the former Trimmer Springs Resort and was originally constructed to facilitate access to the Sanger Log Flume.  Trimmer Springs Road was heavily modified and elongated after construction of Pine Flat Dam broke ground in 1947.   Part 1; the history of Trimmer Springs Road Much of the original alignment of Trimmer Springs Road was constructed to facilitate access to the Sanger Log Flume.   The  Kings River Lumber Company  had been established in 1888 in the form of a 30,000-acre purchase of forest lands in Converse Basin.  This purchase lied immediately west of Grant Grove and came to be known as "Millwood."  The co...

When was Ventura Avenue east of downtown Fresno renamed to Kings Canyon Road? (California State Route 180)

California State Route 180 was one of the original Sign State Routes designated in August 1934.  The highway east of Fresno originally utilized what was Ventura Avenue and Dunlap Road to reach what was then General Grant National Park.  By late year 1939 the highway was extended through the Kings River Canyon to Cedar Grove.   In 1940 General Grant National Park would be expanded and rebranded as Kings Canyon National Park.  The Kings Canyon Road designation first appeared in publications circa 1941 when the California State Route 180 bypass of Dunlap was completed.  Kings Canyon Road ultimately would replace the designation of Dunlap Road from Dunlap to Centerville and Ventura Avenue west to 1st Street in Fresno.   The Kings Canyon Road would remain largely intact until March 2023 when the Fresno Council designated Cesar Chavez Boulevard.  Cesar Chavez Boulevard was designated over a ten-mile corridor over what was Kings Canyon Road, remaini...