Auxiliary lanes

In February 2006, GDOT let two bids to add auxiliary lanes in both directions on the road shoulder, in between two pairs of short-spaced exits. The larger project was in Woodstock between SR 92 and Towne Lake Parkway, where nearly $2 million (equivalent to $2.81 million in 2022^[5]) were spent. This was in a mainly grassy area next to a recreational vehicle dealership on the east (northbound) side. On the opposite side, it required a noise barrier wall north of Dupree Road because of its proximity to existing homes. The other bid was for a much shorter distance of just a few yards or meters on the northeast side of Canton, between SR 20 (Cumming Highway) and SR 5 Business (SR 5 Bus, Riverstone Parkway).

Relocation of SR 5

I-575 is now cosigned throughout its length with SR 5, which was completely removed from its former alignment in 1985–1986 over a nearly 70-mile (110 km) stretch from Marietta all the way to north of Ellijay—far beyond the I-575 terminal point. SR 205 was also deleted when I-575 opened in Cherokee County in 1985, returning what is now the northernmost part of Bells Ferry Road to local responsibility. Part of its old route was briefly designated by a state project route number that appeared on maps as SR 754. This mostly consisted of a widening project planned on the route. The counties along the way did not want to fund it since the route had been state-maintained and then returned to county maintenance in 1986. When Woodstock rejected that widening project (as it would have destroyed its downtown area), SR 754 was truncated south of SR 92, and it was fully turned back in 2001 when the entire project was completed. SR 754 was not signed; however, it continued to appear on Google Maps and other Web mapping services until the mid-2010s. SR 205 has yet to be removed from Google Maps as of 2022 and is still shown on the northern end of Bells Ferry Road.

Most of the former SR 5 did not get such treatment, and all of it was originally deleted except a portion in Canton designated as SR 5 Bus and another part that joined SR 372 to the new route using part of the old route. Another such SR 5 Bus was added from old SR 5 in Ball Ground in 1989, completing a business loop through Ball Ground that is still largely covered by SR 372. Georgia SR 5 continues northward cosigned with SR 515, Corridor A of the Appalachian Development Highway System. Along this route, SR 5 and SR 5 Alternate (SR 5 Alt) have been abandoned by the state and left to the counties and cities to maintain. The Georgia Northeastern Railroad still follows much of the old route.

SR 20 exit

The I-575 and SR 20 interchange was originally a half trumpet/diamond interchange. Since SR 20 has always been a heavily traveled east–west highway, traffic buildup was a common occurrence. When Sembler Properties initiated plans to construct Canton Marketplace in conjunction with a much larger mixed-use plan (Canton Place), developers sought to redesign the interchange for a more effective design. In 2009, work on the new interchange was completed and has a full diamond interchange with one trumpet to I-575 south from SR 20 west and to Main Street from I-575 north. This is effective because it eliminates the use of traffic signals for two left-turning lanes thereby reducing traffic buildup on the two-lane road in front of Canton Place.

Widening

The southern part of I-575 was slated to be widened to a total of six through lanes in the next few years, as part of the Northwest Corridor Express Lanes plan from the Georgia Regional Transportation Authority (GRTA). The extra lane in each direction would extend up to Sixes Road and was planned to be an HOV/HOT lane, with special exits at smaller roads that currently do not have any direct access. The GRTA proposes bus rapid transit along the route.

There would also be separate new HOV ramps built to southbound and from northbound I-75. That highway was proposed to have eight lanes added to it, with one pair going straight to I-575. All widening on I-575 would be done in the median.

In 2009, the plan was scaled-back to include two reversible lanes on I-75, with one extending up I-575.

Ridgewalk Parkway/Rope Mill Road

A new exit (designated exit 9) was approved in October 2005 by GDOT at Ridgewalk Parkway (formerly Rope Mill Road), between Towne Lake Parkway and Sixes Road. Projected to cost $22 million, the new exit will consist of a full diamond interchange and a widened overpass, to benefit the Ridgewalk commercial development on private land adjacent to the new exit.^[6] In addition, the project is part of a greater plan to create a northern bypass of Woodstock, connecting north of downtown to Arnold Mill Road, in theory helping to relieve some of the congestion in the traffic-prone downtown area. The current east–west connection through downtown is restricted to two lanes since recent development was allowed that blocked one-way Mill Street from being extended eastward (which would have allowed Arnold Mill Road/Towne Lake Parkway to carry only westbound traffic through downtown).

During construction of this section of I-575 in the early 1980s, the current overpass was constructed to provide access to private property and the now-defunct Little River Wildlife Management Area, which was later abandoned by the state. The bridge was also a connection to a severed alignment of new Rope Mill Road west of I-575, which originally ran on a north–south alignment from Woodstock to Lebanon before the bridge over the Little River was removed in the early 1990s. The southernmost part of that alignment of Rope Mill Road was realigned eastward through forest land so as to meet Ridgewalk Parkway across from the northern end of Woodstock Parkway. This was done to accommodate the new northbound entrance ramp and opened in early October 2011.

The Federal Highway Administration (FHWA) officials had earlier rejected the plan due to its proximity to two other exits. The FHWA later approved the new exit after forcing GDOT to add auxiliary lanes all the way to and from the next exit in both directions, including the cost of widening the Little River bridges and the removal of hillsides, as well as metal walls designed to block noise rather than for their looks. There had also been a plan to put only a half diamond exit on the north side of the road, using Woodstock Parkway on the east side and a new access road on the west side to connect it to Towne Lake, which would then have its ramps on the north side removed. Woodstock Parkway would have become northbound-only, with the new road being southbound only. This was objected to by residents who would have been adjacent to the new road.^[7]

Sixes Road widening

Sixes Road was widened from a two-lane road to a four-lane divided highway west of I-575 to Bells Ferry Road, where it continues into the BridgeMill development. The short section east of I-575, to where it ends at old SR 5, has also been widened to four lanes. In 2013, the bridge crossing over I-575 was widened to bring it to four lanes. I-575's ramps were also expanded as well. In addition, a larger shoulder was constructed going north from the new Rope Mill exit.