But Atlantans who stay behind might also experience another rare phenomenon—decreased traffic.

“We are looking at the possibility of an overall reduction in rush hour traffic, as people might be taking the day off and traveling out of town to see the eclipse, although just how much traffic could be reduced is hard to predict,”said Scott Higley, the DOT’s director of strategic communications.

Candace Lee, president of Towns County Chamber of Commerce, is also uncertain of the eclipse’s effects. “We really don’t have an estimate of how many visitors we’ll have because we’ve never experienced anything like this before, but the majority are coming from places just south of the path of totality, like Cumming, Canton and Atlanta,” she said.

Fewer cars in Atlanta, however, means increased traffic in parts of the state lacking interstates and highways that aren’t as equipped to handle large amounts of travelers, Higley said. Visitors headed to eclipse-related events in Rabun, White, Habersham, Towns and Union counties will rely on State Route 15/US 441, and State Route 2/US 76.

Local law enforcement offices in those counties are coordinating with state traffic agencies to handle the increased volume of cars on the road to direct and manage traffic. Construction-related lane closures will be restricted to prevent excessive backlog of traffic. GDOT Hero trucks and CHAMP truck operators will be on call for any safety concerns.

“We will treat that day similar to a holiday travel weekend due to the volume that will be traveling into and back out of the mountain areas for various eclipse events,” said Brent Cook, the Gainesville District Engineer.

“If you want to go see the total solar eclipse, we are advising people to plan to leave the day before or even take the whole weekend and make a trip out of it,” Higley said. “Do not think you can get in the car at noon and get to one of these eclipse-viewing spots.”

School systems in the metro Atlanta area are extending hours to allow students to watch the solar eclipse, and to prevent students and employees from being on the roadways during the hours of the eclipse. A longer school day may decrease traffic at the normal end-of-school hours, but could end up increasing traffic later in the day, officials say.

The DOT also warns drivers not to pull over or park along the shoulder of roads, highways or interstates. “Travelers need to be aware that delays along these corridors are inevitable and pulling over or parking on the shoulder is unsafe,” Cook said, so they should exit the roadway and park in a safe area away from traffic before viewing the eclipse.

If driving during the hours of the eclipse, drivers should turn on their headlights as the conditions will be like nighttime travel. Don't look at the sun while driving, or wear the opaque sun shades while driving. If planning to stop and view the eclipse, remember to wear special eclipse-viewing glasses. In case of any problems, drivers can call 511. Eclipse-viewing glasses are available for free at several locations around Atlanta.

Read the ultimate guide to the August 21 solar eclipse at AJC.com.

VIDEO: More on the 2017 solar eclipse