Ernest W. Barrett Parkway (more commonly Barrett Parkway) is a major thoroughfare in the northwestern part of the Atlanta metropolitan area, in the north-central part of Cobb County, in the U.S. state of Georgia. It travels from the southeastern edge of Kennesaw to a point north of Marietta, and continues on in both directions under other names. The portion of Barrett Parkway between Interstate 575 (I-575/SR 5) and US 41/SR 3 (Cobb Parkway) is designated State Route 5 Connector. The road is named after Ernest W. Barrett, the first chairman of the Cobb County Board of Commissioners in the 1960s, after home rule was enacted under a Georgia State Constitution amendment. The initial portion was constructed through Barrett family land, enabling it to be later sold for major development.
Much of the original Barrett Parkway was taken from the two-lane Roberts Road, which generally went from Cobb Parkway (constructed around 1949 for US 41) to Bell's Ferry Road and served an area that was rural in nature. During the 1980s, dramatically-increased land development, most notably the extension of I-75 in 1977 (which cut Roberts Road in half south of Barrett Parkway), the construction of I-575 in 1980, and the completion of the major regional Town Center at Cobb shopping mall in 1986, strained the road to capacity, and was subsequently widened to six lanes (three in each direction, plus turn lanes) with a median by the Cobb County Department of Transportation. Turn lanes were only at the numerous traffic lights. In the mid-1990s, Barrett Parkway was extended by a completely new median-divided highway southwest of US 41 to Burnt Hickory Road, then by widening Ridgeway Road south to SR 120, west of the city of Marietta. This was briefly called West Cobb Parkway (which created potential confusion with Cobb Parkway).
Today, Barrett Parkway is densely packed east of Old 41 Highway with major shopping centers and restaurants. West of Old 41 Highway, Barrett Parkway is mostly residential, but increasingly commercial near the intersection of SR 120 (Dallas Highway). The southeast side of the road is more affiliated with Marietta and the northwest more with Kennesaw. A large industrial park lies to the west. Stilesboro Road east from Barrett Parkway, and Old US 41 south from it, meet at the historic Kennesaw Mountain National Battlefield Park, next to the visitor center.
Barrett Parkway is unique in that even though it is a major area route, it remains under local control (with exception to the state route portion) and was built entirely with county funds. Combined with the East–West Connector and Cumberland Parkway, the route doubly serves as a western bypass of Marietta and connects the two major malls of the county, Cumberland Mall and Town Center at Cobb. The route could possibly also carry a bypassed SR 5 in the future, as the city of Marietta has been planning to have it moved away from downtown Marietta entirely, though no action has yet been taken on that measure.
Renaming
In 2003, the county commission extended the name of the parkway southward along other roads. This included the short Ridgeway Road (to which the parkway itself was extended) which originally ran only from Burnt Hickory Road in the north, about south to SR 120. Villa Rica Road, which was realigned westward at SR 120 to meet Ridgeway to complete the loop, also had its parkway-widened portion renamed. Where a new highway was built to replace Villa Rica Road, what became "Old Villa Rica Road" at the time was then returned to being just "Villa Rica Road" again. The very short Villa Rica Way at SR 120 still retains that name, but was the original northern terminus for Villa Rica Road before its realignment to meet Ridgeway.
As a result of these changes, the Barrett Parkway name now ends at the east–west Connector near Austell. Its northeastern end is at Bells Ferry Road, east of which it continues as Piedmont Road (not to be confused with SR 237, the Piedmont Road in Atlanta). That road curves down around to the south, meeting SR 120 again on the other side of Marietta; here SR 120 is called Roswell Road.
In November 2009, the long viaduct over the flood plain of Noses Creek and its tributary Ward Creek was named the William "Bill" G. Jordan Bridge, in honor of the civil engineer who designed it. It is located south of Villa Rica Road and north of Macland Road (SR 360) at . Due to the environmental impact, this was the last and most expensive section to be built.