City hearing examines DDI proposal for I-285 and Roswell Road as residents warn of business and pedestrian impacts

Consultants from Gresham Smith told Sandy Springs officials March 17 that the preferred concept for the I-285/Roswell Road interchange is a diverging-diamond interchange (DDI) that produced the highest benefit-cost ratio in a city-funded scoping study.

"This is simply a scoping study with the only deliverable being an approved concept," Joel C. Graves of Gresham Smith told the council, stressing the study does not include preliminary engineering, right-of-way acquisition or construction funding. He said the DDI concept fits within constraints created by planned express-lane infrastructure and estimated the interchange work at roughly $70 million to $85 million.

The presentation reviewed existing conditions—Roswell Road carries about 40,000 vehicles a day through the interchange, right-of-way varies dramatically in the corridor and there are numerous utilities both aerial and underground. Graves warned that the project will require complicated utility relocations and staging plans and that at least three GDOT design variances are likely (median width, access control and lateral offsets near existing poles and buildings).

Council members pressed the design team on likely local effects. "This is probably one of the most pedestrian-trafficked areas of the entire city," Councilmember Melissa Mueller said, and cautioned that widening and traffic patterns could hurt small businesses and daily walkers. She asked about a gas station that the team flagged as a potential displacement parcel and about access and parking for a nearby ice arena; the consultants said parcel impacts cannot be confirmed without a full field survey and 3D renderings, which they expect to share with neighborhoods in April or May.

Council members also pressed for wider multi-use paths and barrier-protected crossings. Graves said the proposed bridge would include a roughly 19-foot protected multi-use path, but that a wider multi-use path on all segments may not fit without additional right-of-way or design changes: "I welcome a 10-foot path, but I don't want to overpromise," he said.

State coordination is already under way. Nebby Nagash of the Georgia Department of Transportation confirmed the bridge work is being coordinated with the 285 express-lanes project and said the concept report will be presented to GDOT executive management; he also said public involvement will be part of any preliminary-design phase.

Council members repeatedly urged robust, multilingual public engagement and early outreach to businesses that could be affected. Several members asked the consultants to provide the micro-simulation and rerouting results for side streets and private-access roads so council and staff can evaluate whether cul-de-sac closures or access changes would meaningfully worsen side-street congestion or affect emergency response times.

Because the study is at scoping level, consultants emphasized plans are still fluid and refinements are likely if the project moves into preliminary design. The council did not take action on the concept at the meeting; members said they expect further briefings and community meetings before any design is advanced to right-of-way or construction phases.