|Maintained by GDOT|
|Length:||63.98 mi (102.97 km)|
|Existed:||1969 – present|
|Beltway around Atlanta|
| I-20 in Atlanta
I-75 near Smyrna
SR 400 in Sandy Springs
I-85 near Doraville
I-20 near Panthersville
I-75 near Forest Park
I-85 near College Park
Interstate 285 (I-285) is an Interstate Highway loop encircling Atlanta, Georgia, for 63.98 miles (102.97 km). I-285 is also un-signed State Route 407, and is colloquially referred to as the Perimeter. Suburban sprawl has made it one of the most heavily traveled roadways in the United States, and portions of the highway slow, sometimes to a crawl, during rush hour. It is also signed as Atlanta Bypass on Interstate 75 and Interstate 85.
Route description 
|This section may require cleanup to meet Wikipedia's quality standards. (July 2011)|
It is eight to 12 lanes wide, with the northern part from I-75 to Georgia 400 to I-85 the most heavily traveled. One segment of the highway near Spaghetti Junction (a large, flyover highway interchange northeast of Atlanta) with Interstate 85 widens to 18 lanes, including collector-distributor lanes. Exits are numbered clockwise, starting at the southwestern-most point at I-85, and ending just east of there where it meets I-85 again near Hartsfield-Jackson Airport.
Between I-85 and I-20 in southwest Fulton County, I-285 is designated as the "Bob A. Holmes Freeway", where I-285 heads north, and has an interchange with the Langford Parkway. Between I-20 in northwest Atlanta and I-75 near Cumberland Mall, it is designated as "James E. 'Billy' McKinney Highway" as it continues north, and starts to curve to the east just west of the I-75 interchange.
The northern portion of I-285, east of the "Cobb Cloverleaf" (I-75 junction) to "Spaghetti Junction" (I-85 junction), is frequently referred to as the Top End Perimeter. This section, which includes an interchange with Georgia 400 at exit 27 (frequently cited as the most dangerous intersections in Atlanta), is one of the busiest freeways in the United States, handling about 250,000 cars per day and crossing through three counties. Through that stretch, the freeway expands from six or eight lanes to between ten and fourteen lanes.
Much of Atlanta's high-end commercial real estate has developed along I-285, particularly at the northwestern I-75 and the Georgia 400 junctions. Notable buildings include the 35-story King and Queen towers in the Perimeter Center business district and the Cobb Galleria complex in the Cumberland/Galleria area.
East of the Spaghetti Junction, I-285's direction switches from east to south, as it connects with the Stone Mountain Freeway at exit 39, and intersects with I-20 at exit 46, where I-285 starts to curve towards the southwest. At exit 52, it intersects with Interstate 675, and heads straight west after the intersection with I-75 near the Hartsfield-Jackson Atlanta International Airport.
A portion of the section between I-75 and I-85 on the south side of I-285 has been bridged with a new runway and taxiway of Hartsfield-Jackson Atlanta International Airport, the only interstate in the nation to a have an underpass on a runway (underpasses for taxiways do occur elsewhere). Computer animations were developed prior to construction to simulate a jumbo jet touching down on the runway from a driver's perspective. The entire highway within the tunnels is outfitted with stopped-vehicle sensors and fire detectors. Two electronic signs on either side of the tunnels can warn drivers if the tunnel is closed in an emergency. For 1.21 miles (1.95 km) in the southwest corner, I-85 occupies the median of I-285, yet the roadways remain separate.
Heavy trucks traveling through (but not into) Atlanta are required to bypass the city on I-285, as there is a well-signed and heavily enforced ban on through truck traffic along I-75, I-85, I-20, Georgia 400, and many other major Atlanta thoroughfares. As with highways just outside I-285, trucks are also prohibited from the far-left one or two lanes (except where there are left exits open to trucks).
The complete circumference of I-285 is covered by Georgia NaviGAtor, Georgia's intelligent transportation system (ITS). One-hundred fifty-three CCTV traffic cameras, twenty-six electronic message signs and traffic-detection sensors have been installed in phases between 1999 and 2010 by Georgia DOT. Additionally, ramp meters are present at nearly all entrance ramps onto I-285, with the exception of the southeast section of I-285 and the major freeway-to-freeway connection ramps.
To many residents of Atlanta, the Perimeter defines a useful boundary to separate metro Atlanta's core from its surrounding suburbs. People distinguish a location as being inside or outside the Perimeter, sometimes abbreviated as ITP and OTP, a recent local neologism. This was also the rough boundary chosen by BellSouth for separating landline telephone exchanges in suburban area code 770 from the existing area code 404 in 1995.
I-285 was opened on October 15, 1969 at a cost of $90 million, as a four-lane freeway throughout (two lanes each way).
The reconstruction of I-285, particularly on the top-end and the Spaghetti Junction reconfiguration (covered by the revive285 project), has cost about $355 million.
Until 2000, the state of Georgia used the sequential interchange numbering system on all of its Interstate highways. The first exit on each highway would begin with the number "1" and increase numerically with each exit. In 2000, the Georgia Department of Transportation switched to a mileage-based exit system, in which the exit number corresponded to the nearest milepost.
Since the 1970s, the Georgia Department of Transportation has planned an outer loop, which would be a roughly 230 mile (370 km) circumferential loop around metropolitan Atlanta. Under Governor Sonny Perdue, the plans were dropped from the Regional Transportation Plan, in favor of the expansion of the rural state road network outside of Atlanta. The state still retains ownership of most of the land that would be needed to complete at least the northern section of the Outer Loop, known as the Northern Arc. As of 2007[update], ideas have been considered to build that highway even further north, through areas that are still rural.
The I-285 and Georgia 400 interchange is slated to be reconfigured with collector/distributor roads along Georgia 400 and a complete full stack interchange that will make it the largest freeway interchange east of Los Angeles. The new interchange is expected to be able to handle around 300,000 cars per day. Feasibility studies have been completed, and it is in Atlanta's 2025 Regional Transportation Plan.
On July 31, 2012, metro-area voters rejected the T-SPLOST comprehensive transportation plan that was to be funded by an additional one-percent sales tax over a ten-year period. Among the projects included in the plan was a new exit on I-285 at Greenbriar Parkway on the southwest side of Atlanta (between present exits 2 & 5), as well as major reconstruction of interchanges at exits 27 (GA 400/US 19), 10 (I-20 west of Atlanta) and 33 (I-285 northeast of Atlanta).
Georgia DOT voted in September 2012 to raise the speed limit from 55 miles per hour (90 km/h) to 65 miles per hour (105 km/h) on the entire freeway, and by 2013 install electronic signs for variable speed limits north of I-20, to lower the speed limit when traffic or weather conditions warrant. This is intended to keep traffic moving at a reduced but steady speed, rather than suddenly braking drivers causing traffic to "clot" simply because other drivers are also braking (which causes unnecessary stop-and-go traffic).
Exit list 
The following exits are listed clockwise from the southwest: going south to north, west to east, north to south and east to west. An exception is that heading counterclockwise, exit 33 comes before exit 34.
|County||Location||Mile||km||Old exit||New exit||Destinations||Notes|
||East Point||2||1||Washington Road|
|3||2||Camp Creek Parkway (SR 6) – Domestic Terminals|
|Atlanta||4||5||SR 154 / SR 166 (Langford Parkway, Campbellton Road)||Signed as exits 5A (north/east) and 5B (south/west)|
|5||7||Cascade Road||Former SR 154|
|Atlanta||6||9||SR 139 (Martin L King Jr. Drive) – Adamsville|
|7||10||I-20 (Ralph D. Abernathy Freeway, Tom Murphy Freeway) – Atlanta, Birmingham||Signed as exits 10A (east) and 10B (west)|
|8||12||US 78 (Hollowell Parkway) / US 278|
|9||13||Bolton Road||Clockwise exit and counterclockwise entrance; former SR 70|
||Smyrna||10||15||SR 280 (South Cobb Drive) – Smyrna|
|11||16||South Atlanta Road – Smyrna||Former US 41 / SR 3|
|12||18||Paces Ferry Road – Vinings|
|13||19||US 41 (Cobb Parkway) – Dobbins ARB||Counterclockwise exit is part of exit 20|
|14||20||I-75 – Atlanta, Marietta||Cobb Cloverleaf|
||Sandy Springs||15||22||Northside Drive, New Northside Drive, Powers Ferry Road|
|17||25||US 19 south (Roswell Road) – Sandy Springs||Counterclockwise end of US 19 overlap|
|18||26||Glenridge Drive, Glenridge Connector||Clockwise exit and counterclockwise entrance; former SR 407 Loop|
|19||27||US 19 north / SR 400 – Atlanta, Dahlonega, Cumming||Clockwise end of US 19 overlap|
|20||28||Peachtree-Dunwoody Road||Counterclockwise exit and clockwise entrance|
||Dunwoody||21||29||Ashford-Dunwoody Road||Diverging diamond interchange (completed June 3, 2012)|
|22||30||Chamblee-Dunwoody Road, North Shallowford Road, North Peachtree Road|
|23||31||SR 141 (Peachtree Industrial Boulevard) – Chamblee||Signed as exits 31A (south) and 31B (north)|
|24||—||Tilly Mill Road/Flowers Road||Exit removed in the 1990s during I-285 reconfiguration|
|Doraville||25||32||US 23 (Buford Highway) – Doraville|
|26||33||I-85 – Atlanta, Greenville, Charlotte||Spaghetti Junction; signed as exits 33A (south) and 33B (north) clockwise|
|Tucker||27||34||Chamblee-Tucker Road||Clockwise exit is part of exit 33A|
|27A||36||Northlake Parkway||Clockwise exit and counterclockwise entrance|
|28||37||SR 236 (LaVista Road) – Tucker|
|29||38||US 29 (Lawrenceville Highway)|
|Stone Mountain||30||39||US 78 – Decatur, Atlanta, Snellville, Athens||Signed as exits 39A (west) and 39B (east)|
|31||40||East Ponce de Leon Avenue – Clarkston||Clockwise exit and counterclockwise entrance|
|31||40||Church Street – Clarkston||Counterclockwise exit and clockwise entrance|
|32||41||SR 10 (Memorial Drive) – Avondale Estates|
|32A||42||Indian Creek Transit Station||Counterclockwise exit and clockwise entrance|
|33||43||US 278 (Covington Highway)|
|34||44||Glenwood Road||Former SR 260|
|Panthersville||35||46||I-20 (Ralph D. Abernathy Freeway, Purple Heart Highway) – Atlanta, Augusta, Columbia||Signed as exits 46A (west) and 46B (east) counterclockwise|
|36||48||SR 155 (Flat Shoals Road, Candler Road)|
|38||52||I-675 south – Macon|
|39||53||US 23 (Moreland Avenue) – Fort Gillem|
||Atlanta||40||55||SR 54 (Jonesboro Road) – Forest Park|
||41||58||I-75 – Atlanta, Macon, Tampa, Maynard Jackson International Terminal|
|Domestic Terminal||42||59||Clark Howell Highway, Loop Road – Air Cargo||Clockwise exit is part of exit 58|
|43||60||SR 139 (Riverdale Road)|
||College Park||44||61||I-85 – Columbus, Montgomery, Int'l Airport, Atlanta|
|1||62||SR 14 Spur (South Fulton Parkway) / SR 279 (Old National Highway)|
See also 
- Route Log - Auxiliary Routes of the Eisenhower National System Of Interstate and Defense Highways - Table 2
- Georgia's Interstate Exit Numbers Georgia Department of Transportation - online. Accessed April 30, 2007.
- Interstate 20 Exit Renumbering Page Georgia Department of Transportation - online. Accessed April 30, 2007.
- AJC - 285 may see variable speed limit signs
- Mike Morris and Patrick Fox (June 4, 2012). "First Monday commute on new interchange goes smoothly". The Atlanta Journal-Constitution. Retrieved June 4, 2012.
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