Atlanta's transportation infrastructure comprises a complex network that includes a heavy rail rapid transit system, a light rail streetcar loop, a multi-county bus system, Amtrak service via the Crescent, multiple freight train lines, an Interstate Highway System, several airports, including the world's busiest, and over 45 miles (72 kilometres) of bike paths.
Atlanta has a network of freeways that radiate out from the city, and automobiles are the dominant means of transportation in the region. Three major interstate highways converge in Atlanta: I-20 (east-west), I-75 (northwest-southeast), and I-85 (northeast-southwest). The latter two combine in the middle of the city to form the Downtown Connector (I-75/85), which carries more than 340,000 vehicles per day and is one of the most congested segments of interstate highway in the United States. Atlanta is mostly encircled by Interstate 285, a beltway locally known as "the Perimeter" that has come to mark the boundary between "Inside the Perimeter" (ITP), the city and close-in suburbs, and "Outside the Perimeter" (OTP), the outer suburbs and exurbs. The heavy reliance on automobiles for transportation in Atlanta has resulted in traffic, commute, and air pollution rates that rank among the worst in the country.
The Metropolitan Atlanta Rapid Transit Authority (MARTA) provides public transportation in the form of buses and heavy rail. Notwithstanding heavy automotive usage in Atlanta, the city's subway system is the eighth busiest in the country. MARTA rail lines connect key destinations, such as the airport, Downtown, Midtown, Buckhead, and Perimeter Center. However, significant destinations, such as Emory University and Cumberland, remain unserved. As a result, a 2011 Brookings Institution study placed Atlanta 91st of 100 metro areas for transit accessibility. Emory University operates its Cliff shuttle buses with 200,000 boardings per month, while private minibuses supply Buford Highway. Amtrak, the national rail passenger system, provides service to Atlanta via the Crescent train (New YorkNew Orleans), which stops at Peachtree Station. In 2014, the Atlanta Streetcar opened to the public. The streetcar's line, which is also known as the Downtown Loop, runs 2.7 miles around the downtown tourist areas of Peachtree Center, Centennial Olympic Park, the Martin Luther King, Jr. National Historic Site, and Sweet Auburn. The Atlanta Streetcar line is also being expanded on in the coming years to include a wider range of Atlanta's neighborhoods and important places of interest, with a total of over 50 miles of track in the plan.
Hartsfield-Jackson Atlanta International Airport is the world's busiest airport as measured by passenger traffic and aircraft traffic. The facility offers air service to over 150 U.S. destinations and more than 75 international destinations in 50 countries, with over 2,500 arrivals and departures daily. Delta Air Lines maintains its largest hub at the airport. Situated 10 miles (16 km) south of downtown, the airport covers most of the land inside a wedge formed by Interstate 75, Interstate 85, and Interstate 285.
Cycling is a growing mode of transportation in Atlanta, more than doubling since 2009, when it comprised 1.1% of all commutes (up from 0.3% in 2000). Although Atlanta's lack of bike lanes and hilly topography may deter many residents from cycling, the city's transportation plan calls for the construction of 226 miles (364 kilometres) of bike lanes by 2020, with the BeltLine helping to achieve this goal. In 2012, Atlanta's first "bike track" was constructed on 10th Street in Midtown. The two lane bike track runs from Monroe Drive west to Charles Allen Drive, with connections to the Beltline and Piedmont Park. Starting in June 2016, Atlanta received a bike sharing program with 100 bikes in Downtown and Midtown, which expanded to 500 bikes at 65 stations as of April 2017.