Sandy Springs’ southern doorway is up for a massive face-lift if city leaders vote Tuesday to approve a $120 million development on Roswell Road.

But the plan has drawn opposition from some nearby homeowners who fear it will swamp an already overloaded commuter artery and channel traffic through residential streets.

JLB Realty, however, says it has support from many residents for its 21-acre Gateway project. The plan calls for leveling 436 old apartments near Windsor Parkway and putting in 630 high-end units, as well as upscale office and retail space.

The divided sentiment underscores the city’s ongoing conflict to upgrade aging developments along its major corridors while protecting neighborhoods.

“It’s all pretty frightening,” said Susan Heard, who could lose part of her backyard on Windsor Parkway if proposed road work for the project is approved.

The Georgia Regional Transportation Authority has ruled that if zoning is granted for the development, Windsor Parkway should be reconfigured to meet Roswell Road at a right angle instead of the current diagonal. The cost of the upgrade would likely be borne solely by the city.

Heard, a 26-year resident of the area, called the road work invasive and said she worries the cost will siphon money from other street projects in the city.

The city has not released estimates, but City Councilwoman Karen McEnerny said it will cost at least $4.4 million to reconfigure the intersection. The City Council will vote on the road work at Tuesday’s 6 p.m. meeting before the zoning issue is considered.

The Gateway project has been heralded as a major step in Sandy Springs’ efforts to establish a visual identity at its entry points and along its major corridors. The city of 93,000 incorporated eight years ago, in part to get control of runaway zoning that had led to an extraordinarily high inventory of apartment complexes.

McEnerny said she favors upgrading the area, but she’s concerned about density. One of the proposed apartment complexes would be five stories — taller than any building within a mile and a half of the site, she said.

“There’s a reason there is a lack of tall buildings in the area,” she said. “It’s because the network of surrounding streets can’t support the added traffic.”

Sandy Springs Mayor Eva Galambos would not comment on a pending zoning case.

Hudson Hooks, regional partner for JLB, said the venture will be an immediate upgrade, replacing apartments built in the 1960s with upscale retail and housing.

“We’ve worked really, really hard with the neighborhoods over the past couple of years,” Hooks said, adding that two of the affected homeowners’ groups have formally endorsed the project. “From that standpoint, they all understand what we’re trying to accomplish.”

Trisha Thompson, the zoning committee chairwoman for the Sandy Springs Council of Neighborhoods, said that while not everyone supports the development, JLB has made earnest efforts to speak with affected residents.

The project has won conditional support from the High Point Civic Association, which represents more than 1,700 homeowners in southeast Sandy Springs.

Jane Kelley, who sits on the High Point board, is representing homeowners near the proposed development. She has taken a counterview, saying approval of the development would be shortsighted.

“The city is trying to encourage redevelopment with all good intentions,” she said, “but the unintended consequences of allowing runaway density are just huge.”

Approval by the City Council could set dangerous precedents on building heights and parking variances, Kelley said. Also, the city would be giving the developer bonus densities in exchange for redeveloping an old apartment complex, she said.

Some of the dissent extends into Atlanta.

Gordon Certain, the president of the North Buckhead Civic Association, said his group opposes the plan because it will add more traffic to an area already famous for rush hour bottlenecks.