Phase I Archaeological Survey for Interstate 285 Ramps at Riverside Drive, Fulton County, Georgia.

The proposed project is located on Riverside Drive at the interchange with I-285 in Fulton County, Georgia and is within the city limits of Sandy Springs. The project consists of safety improvements to the existing interchange, which will convert the two existing signalized intersections at each ramp terminal with roundabouts.

The current roadway configuration of Riverside Drive consists of one, twelve foot lane in each direction and traffic signals at the ramp termini. There are no left turn lanes at the intersections with the I-285 entrance ramps, resulting in left turning vehicles blocking the through movements to enter I-285. The existing bridge only provides for two lanes of traffic, one northbound and one southbound. The eastbound and westbound I-285 off ramps each consist of a single, sixteen foot lane. There are no existing sidewalks approaching the bridge; however, there are existing sidewalks on the bridge itself. The existing right-of-way along Riverside Drive varies from 50 to 100 feet.

The proposed project will convert the signalized intersections at the ramp termini to single lane roundabouts, one at each intersection. The two roundabouts will be constructed, one on the north side of I-285 and one on the south side of I-285. This configuration prevents traffic from circling completely around each roundabout, instead forcing vehicles that enter the roundabout to cross the bridge over the interstate and into the second roundabout on the opposite side. The advantage of this configuration is that traffic crossing the bridge does not have to yield to other vehicles within the approaching roundabout. Each approach to the roundabout will be widened to two lanes with one lane entering the roundabout and the other serving as a right turn lane. Sidewalks will be added to both sides of the roadway along Riverside Driveway within the limits of the project. The project is approximately .5 mile in length.

The project may also include auxiliary lanes along Riverside Drive between I-285 WB ramps and Heards Ferry Road including intersection modification at the Heards Ferry Road intersection to improve traffic operations. If the auxiliary lanes are included, it would entail a northbound lane approximately 900 feet in length from the northern roundabout to Heards Ferry and a 700-foot southbound lane from Heards Ferry to the right turn lane for the northern roundabout. The surveyed ESC area included the possible auxiliary lanes.

The project will also include routine rehabilitation of the existing bridge. This work includes replacement of the joints at bent 2 and abutments 1 and 5. All construction joints will be resealed and the bridge deck will be sealed with a two-part polymer overlay. Concrete spalling will be repaired on bents 3 & 4 and abutment 5.