Georgia State Route 400

Route information
Length	53.75 mi (86.50 km)
Existed	1971, 1993–present
Location
Country	United States
State	Georgia
Highway system
	Georgia State Highway System; Interstate; US; State; ; Special;

State Route 400 (always known locally as Georgia 400 or just 400, or by its nickname, the "Alpharetta Autobahn") is a highway in the U.S. state of Georgia, muliplexed with U.S. 19 from exit 4B until its terminus just south of Dahlonega. Georgia 400 goes from Atlanta, at I-85, to Buckhead, Sandy Springs, Roswell, Alpharetta, Cumming, Dawson County, and Dahlonega. Like the interstate highways, it is a limited access road (with exit ramps instead of intersections), but unlike the interstates (which were renumbered by the GDOT in 2000), the exit numbers do not indicate mileage: they still go up sequentially one-by-one. Once 400 passes exit 17 (S.R. 306), it changes from a limited access highway into an at-grade divided highway.

Between Interstate 85 and Interstate 285, Georgia 400 is designated "T. Harvey Mathis Parkway"; upon reaching the Perimeter and beyond, the highway is designated "Turner McDonald Parkway".

History

Original Portion (I-285 to S.R. 306)

The initial section north of I-285 was officially dedicated on May 24, 1971^[2] and subsequent additions to the north opened in stages through 1981. The road was subsequently widened in 1989 from its original four lane configuration to eight lanes between I-285 and Holcomb Bridge Road. The widening projects were necessitated by the massive growth that Georgia 400 brought to northern Fulton County and Forsyth County. In December 2005, the Georgia Department of Transportation began widening the section from Holcomb Bridge Road to Windward Parkway from three to four lanes in the northbound direction and from two to three lanes from Windward Parkway to McFarland Parkway. Southbound, the highway is being widened to three lanes between McFarland Parkway and Holcomb Bridge Road. In addition, sound barrier walls and a concrete divider in the median are also being added. The project is expected to be finished by September 2007.

Toll Portion (I-85 to I-285)

The southern section of Georgia 400 (from I-285 to I-85) was the last section to be constructed. It is the only active toll road in Georgia, after the F.J. Torras Causeway toll between Brunswick and St. Simons Island in southern Georgia was removed in 2003^[3]. The road opened to traffic on August 1, 1993 after three years of construction. Many remaining residents now live on dead end streets with significant noise pollution. Existing exits were renumbered up by four to accommodate the extension, which has a single toll plaza in the middle of its length. Contrary to public belief, the bonds that funded the construction of Georgia 400 south of I-285 will not be paid off until 2011. There is also currently no direct access from Georgia 400 southbound to I-85 northbound or vice versa, except by a confusing route via Sidney Marcus Boulevard. In addition, the North Line for Atlanta's MARTA system was constructed in the median from the Glenridge Connector to south of Lenox Road and was opened on June 8, 1996.

The Georgia 400 toll plaza, operated by the State Road and Tollway Authority, collects tolls in both the northbound and southbound directions. Each direction has two open-road toll lanes, which collect tolls at highway speeds using the Georgia Cruise Card electronic tag, and seven gated toll lanes which accept either cash or Cruise Cards. The toll facility handles a total of approximately 120,000 vehicles per day. About 37% of transactions are paid via Cruise Card.

At one time, Georgia 400 was to connect to Interstate 675 in DeKalb County; however, residents in northern DeKalb County did not want the highway to cut through their neighborhoods and had the idea killed.

Major cities

Bolded cities are officially-designated control cities for signs.

Atlanta
Cumming
Dahlonega

Exit list

The following exits are listed south to north and are numbered sequentially.

County	Location	#	Mile	Destinations	Notes
Fulton	Atlanta		0.0	I-85 South – Downtown Atlanta, Atlanta Airport	Unsigned S.R. 403; southern terminus.
		1		Sidney Marcus Boulevard – To I-85 North	Northbound: entrance only; southbound: exit only.
		2		S.R. 141 Conn (Lenox Road)	Single-point urban interchange
		Toll plaza – 2 axle vehicle $.50, 3 axles $1.50, $.50 per additional axle
	Sandy Springs	3		Glenridge Perimeter Connector	Formerly S.R. 407 Loop. Northbound use exit 4A.
		4A		I-285 East – Greenville, Augusta	Unsigned S.R. 407.
		4B		I-285 West, U.S. 19 South – Marietta, Chattanooga, Birmingham	Unsigned S.R. 407.
		joins North
		5		Abernathy Road – Dunwoody, Sandy Springs	Split into 5A (Dunwoody) and 5B (Sandy Springs) northbound only.
		5C		North Springs MARTA station	Northbound: entrance only; southbound: exit only.
		6		Northridge Road
	Roswell	7		S.R. 140 (Holcomb Bridge Road) – Roswell, Norcross	Split into 7A (Norcross) and 7B (Roswell) northbound only.
	Alpharetta	8		Mansell Road	North Point Mall
		9		Haynes Bridge Road	North Point Mall
		10		S.R. 120 (Old Milton Parkway) – Alpharetta
		11		Windward Parkway
Forsyth		12		McFarland Parkway	Split into 12A (east) and 12B (west) northbound only.
		13		S.R. 141 (Peachtree Parkway) – Cumming, Norcross
		14		S.R. 20 – Cumming, Sugar Hill, Buford	Lake Lanier Islands; will be split into separate east- and westbound exit ramps northbound only (estimated fall 2006).
	Cumming	15		Bald Ridge Marina Road	Bald Ridge Marina, Cumming Fairgrounds
		16		Pilgrim Mill Road	Lake Sidney Lanier
		17		S.R. 306 (Keith Bridge Road) – Cumming, Gainesville
		Freeway ends; continue