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Transportation Project Resources

Diverging Diamond Interchange (DDI)


A Diverging Diamond Interchange is a new type of intersection design that can increase capacity, decrease congestion, and enhance safety.

Two DDIs are planned for Cobb County: Windy Hill Rd/I-75 and Wade Green Rd/I-75.

Windy Hill Road Diverging Diamond Interchange

 In January 2016, construction of a Diverging Diamond Interchange began on Windy Hill Road. Keep track of project updates here.

Flashing Yellow Arrow

Flashing Yellow Arrow

A flashing yellow arrow is part of a new signal display system that more clearly indicates to drivers when they must yield before making a left turn across traffic.

As of April 2015, Cobb County has 14 FYA signals. 

GIS at Cobb DOT


GIS map roads

Cobb's Geographic Information System (GIS) plays a huge role in supporting Cobb DOT's projects and operations. Check out GIS by the numbers.


A roundabout

A roundabout is a circular intersection where traffic flows around a center island. Roundabouts enhance safety, are more efficient and have a higher traffic capacity. Cobb County has six roundabout projects (2015).

Traffic Counts

Traffic Counts GIS map

The Cobb County Department of Transportation collects and maintains a traffic count database for most roads within the County. The Traffic Count Map includes counts taken from the last 3-4 years and is periodically updated.

The counts are the Average Daily Traffic (ADT), which is a 24-hour count of vehicles for both directions of travel.

View Cobb County traffic counts, supported by GIS mapping.

  • Click on a triangle to get traffic count data for that location.
  • Use the search box to locate an address, intersection, or point of interest.
  • Share the map with others or print a map to a PDF document.

The Georgia Department of Transportation also maintains a traffic count database for roads within Cobb County. For inquiries regarding GDOT traffic count data, call (770) 986-1436 or visit the

Traffic Operations

Traffic Operations oversees the county's traffic signal systems and operates an Advanced Traffic Management System (ATMS). The division also issues permits to utilities desiring to locate on County right-of-way and oversees pavement marking and signage issues.

Transportation Management Center

Traffic Management Center

In 2015, Cobb DOT's TMC celebrated the five-year anniversary of its new, state-of-the-art building. Learn more about the DOT's high-tech traffic operations team.

Windy Hill Road

Windy Hill Road Project Infographic

The Windy Hill Road project is a $48 million investment that will transform the corridor. Learn the facts of this five-part project.

Winter Weather Road Safety


Winter brings some of the most dangerous road conditions of the year. Cobb DOT wants to you to be safe by using these quick precautions and tips.