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Project Profile: Windy Hill Corridor Improvements, Cobb County, Georgia

Image of bridge.

Diverging diamond interchanges provide a more efficient and safe travel pattern for vehicular travel with cars no longer required to make left hand turns to access the interstate.

Source: Credit to Cumberland Community Improvement District

Project Name

Windy Hill Corridor Improvements


Cobb County, Georgia

Project Sponsor / Borrower

Cumberland Community Improvement District

Program Areas

Public-Private PartnershipProject FinanceValue Capture

Value Capture Techniques

Special Assessment: Community Improvement Districts & Sales Tax Districts


Local Highway and Bridge


Windy Hill Road serves as the east and west counterpart to U.S. Highway 41/Cobb Parkway connecting Smyrna and points west to Cumberland, Cobb’s central business district. Improvements to the East and West Corridor have been part of the Cumberland Community Improvement District’s work program since its inception in 1988, and the corridor needs them because crashes occur there three times more than the state-wide average.

The project focused on Windy Hill Road from Cobb Parkway to Powers Ferry Road. It included road widening to manage the additional capacity and new medians to promote safer travel. The interchange at I-75 was reconfigured into a diverging diamond interchange (DDI), eliminating the left-hand turns at traffic signals and improving vehicular flow without adding lanes. The project also included a bridgescape feature, streetscapes with new sidewalks, light-emitting diode pedestrian lighting, landscaping, and decorative mast arms.

Circle 75 and Interstate North Parkway were realigned due to the length required for the DDI at Windy Hill and Interstate 75. Circle 75 was also realigned with the Interstate 75 Southbound ramp and Leland Drive with the Pappasito’s Cantina entrance. Vehicles accustomed to turning onto Interstate North Parkway at Pappasito’s Cantina now enter at the Spectrum Circle intersection. Similarly, vehicles traveling northbound on Interstate North Parkway trying to access Windy Hill Road are diverted to the Spectrum Circle intersection. Drivers may continue to make a right turn onto Interstate North Parkway from the Windy Hill Road exit off Interstate 75 Northbound.

A traffic signal was installed to help slow traffic moving onto Interstate North Parkway at the curve adjacent to the Marriott Hotel. Three left-turn lanes were added at Spectrum Circle to handle the extra capacity.

The project, which was Cobb’s first DDI, began in 2015. It was completed in 2017 and continues to provide a more efficient and safer travel pattern.

Cost $46.4 million
Funding Sources
  • CID - $7 million
  • Cobb County - $25 million (SPLOST, a one-penny sales tax)
  • State - $3.4 million
  • Federal - $11 million
Project Delivery / Contract Method


Private Partner C.W. Matthews
Project Advisors / Consultants N/A


Duration / Status

Construction began in 2015 and was completed in 2017.

Financial Status / Financial Performance

The bulk of the project cost came from the Cobb Special Purpose Local Option Sales Tax (SPLOST), a one-penny sales tax.


CID leverage Federal, State, County, & private investments to enhance roads, bridges, streetscapes, bicycle trails, pedestrian enhancements and recreational infrastructure which support and protect commercial value within the district

Use of diverging diamond interchange (DDI), the first in Cobb. DDI provided the following benefits:

  • Eliminated the left hand turns at traffic signals and improved vehicular flow without the addition of extra lanes.
  • Provided a cost-effective solution and improved conditions by 20-30 percent, while eliminating the reconstruction of the existing bridge.
  • Potential for reduced motorist incidents and fatalities, thus increasing road safety for travelers.
Related Links / Articles

Adam Ross
Communications & Outreach Manager, Cumberland Community Improvement District
(770) 859-2326

Cobb DOT Project Manager
James Hudgins
(770) 420-6658

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