area for future settlement, rather than as one to relieve traffic or to link I-75 to an existing city or large town (On the other hand, I-985 was built as a link between I-85 and the preexisting city of Gainesville.) It has since accelerated land development and population growth in the area far beyond what the Georgia Department of Transportation (GDOT) predicted, essentially causing its own traffic. (After just 20 years, it carried as many cars per day as it was expected to in 40 years.) The first stage of I-575 was constructed in 1979 from I-75 to SR 92 near Woodstock and was opened to traffic on October 16, 1980. The next section to SR 20 began construction in 1981 and was opened on March 29, 1985, as far north as exit 11 (now mile 20). The section between the original exit 8 (now exit 16A) and exit 10 (now exit 19) was originally part of the Canton Bypass (SR 20), which was constructed in 1978. The final portion of I-575 to past Howell Bridge Road and SR 372 opened later, and that extended the highway to its present length of , although the northernmost mile () given in this length was not constructed up to Interstate Highway standards since it extends past a surface (at-grade) intersection. This final portion north of Canton was constructed of concrete rather than asphalt, and narrow black lines run on either side of the white lane markings. In 2000, Georgia switched over from a sequential exit numbering system to a mileage-based exit numbering system. The road was last repaved in mid-2009, with funds from the American Recovery and Reinvestment Act of 2009. 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 $ in ) 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