Atlanta has a comprehensive roadway network. Traffic can be pretty congested sometimes.
MARTA operates heavy rail and bus service in Atlanta. The service is reliable if not extensive. Route finding services are available on Google Transit, and they just introduced a real-time information portal.
Cycling for transportation requires some level of courage (for the drivers) and endurance (for the hills). The rewards are there, too! GT has some awesome biking communities, group rides, and campus is bike-friendly. Ask Starter Bikes about getting a bike and/or check out the Bike GT page for advice.
The GT Stinger Buses serve campus and the nearby student areas (Emory, Midtown MARTA, Tech Square, and more). No fare required, just hop on! Read through the routes and download a GT Buses app to track bus locations.