GDOT to Increase Speed Limit on I-285's Top End

Staff Report

The Georgia Department of Transportation will raise the base speed limit on I-285 within Cobb, DeKalb and Fulton counties in the portion that is known as the 'Top End.'

North of the I-20 interchanges will be raised from 55 mph to 65 mph in September to coincide with a similar increase implemented on SouthSide I-285 last fall.

It will be a variable speed limit (VSL), which could be decreased when necessary to accommodate an incident or heavy congestion. 

How Will It Work?

• VSL will allow Georgia DOT to electronically reduce the speed limit in the event of incidents, heavy congestion or severe weather.
• The speed limit will be reduce in 10 mph increments; 65 mph to 55 mph, 55 mph to 45 mph and 45 mph to 35 mph.
• The speed limit expected to remain 65 mph most of the time.
• TMC operators will monitor the roadway for crashes, breakdowns and heavy congestion. When needed for safety purposes, they will make real time adjustments to reduce the speed limit in and leading up to the affected area using active traffic management software.

In a letter letter to stakeholders last year, GDOT Chief Engineer Russell McMurry said:

"The 36 miles of Top End I-285 carry an average of 50,000 more vehicles a day than the southern section, and in some sections, 100,000 more, and have many more or closely spaced interchanges as the southern section. Higher traffic volumes and more interchanges mean more weaving and more merging, which result in congested areas during the rush hour peak times.

“Georgia DOT’s Traffic Management Center operators monitor metro Atlanta roadways round-the-clock for crashes, vehicle breakdowns and heavy congestion. The VSL system will allow our Traffic Management Center operators make instant, real-time adjustments to roadways signage to reduce the speed limit in and leading up to the affected area. They will also simultaneously activate the I-285 overhead changeable message signs to alert motorists of the upcoming reduced speed limit."