SAVANNAH — A proposal to put double-decker tour buses on the streets of Savannah’s historic district has residents rallying to bring the plans to a screeching halt, with critics fearing the buses would hit ancient oak limbs and give sightseers a peeping Tom’s view into Victorian homes.

Two Boston businessmen are lobbying Savannah City Hall to end a 17-year prohibition on double-decker buses in the coastal city’s downtown historic district, which draws 12 million visitors a year. Savannah’s Downtown Neighborhood Association is urging officials to deny the request.

Opponents say the buses, which would have passenger seats on an open-air top, could run into low-hanging branches along the edges of Savannah’s manicured squares. And they complain the elevated views would enable tourists to peer over garden walls and possibly into second-floor windows of private homes.

“What this company is asking us to do is to change our rules so we can be more like everywhere else, when what draws people to Savannah is that we’re not like anywhere else,” said Bob McAlister, who lives in an 1853 row house on Gordon Street in the heart of downtown.

Steve Caplan and Tom O’Connor, the Boston investors, argue they shouldn’t be kept out of the city’s lucrative tourism market — worth $2 billion in 2011 — because of a blanket ban.

The partners say they’re having four buses built to custom specs in England. While they would hold 75 passengers, double the capacity of the tour trolleys Savannah is used to, the buses would stand 12½ feet tall. That’s a foot below the minimum clearance the city requires for maintaining its tree canopy, though residents insist some branches hang lower.

Julie Wade, a Savannah attorney hired by the business partners, said concerns about privacy were overblown.

“We’re not running a peeping Tom tour. The buses will be lower than most second-floor windows,” Wade said. “This isn’t going to dramatically change people’s privacy. Right now you can see right across the street into other people’s properties.”

The city says 96 motorized tour vehicles were operating last year compared to just 40 in 2002. And those numbers don’t include horse-drawn carriages, walking tours and other operators who show off Savannah’s sights without guzzling gas.