Addendum Phase I Archaeological Investigation in Advance of the I-285 Westbound Auxiliary Lane Extension AIP Project, Fulton County, Georgia

This project proposes to construct a 12 foot (ft) (3.7 meter [m]) wide auxiliary lane along Interstate (1-)285 westbound between Roswell Road and Riverside Drive extending the 1-285 westbound Roswell Road onramp currently being reconstructed under the Georgia Department of Transportation's (GDOT) Transform I-285/State Route (SR) 400 project (Pl No. 0000784). The current project, Pl No. 0017130, is an Advanced Improvement Project (AIP). The auxiliary lane would begin approximately 700 ft (213.4 m) east of Riverside Drive and would end approximately 4,000 ft (1 ,219.2 m) west of Roswell Road for a total distance of approximately 1.3 miles (mi) (2.09 kilometers [km]). Between Roswell Road and Riverside Drive, existing 1-285 westbound has five 12 ft (3.7 m) travel lanes with 12 ft (3.7 m) shoulders, except under Mount Vernon Highway bridge, where 2 ft (0.6 m) shoulders exist. A 12 ft (3.7 m) shoulder would be constructed on the north side of the proposed auxiliary lane. The existing right-of-way (ROW) along 1-285 between Roswell Road and Riverside Drive varies between approximately 250 and 600 ft (7 6.2 and 182.9 m). No additional ROW would be required for the proposed project along 1-285.

The proposed project would also require the replacement of the existing Mount Vernon Highway bridge over I-285 (Structure ID 121-0444-0) in order to accommodate the ramp extension. The proposed bridge would be approximately 350 ft ( l 06.7 m) long and 44 ft ( 13.4 m) wide. The bridge would consist of one 12 ft (3.7 m) travel lane in both the northbound and southbound directions over 1-285. The proposed bridge would also include curb and gutter and a 6.5 ft (2 m) sidewalk on either side. The proposed project would construct the new bridge on an off-set alignment to maintain traffic flow during construction. The existing ROW along Mount Vernon Highway varies between approximately 50 and 100 ft (15.2 and 30.5 m). Approximately 0.45 acre (ac) (0.18 hectare [ha]) of additional ROW would be required for the proposed reconstruction of the Mount Vernon Highway bridge and approaching the off-set alignment.