On Nov. 22, the Brentwood City Commission voted unanimously in favor of a new zoning district aimed at protecting Old Smyrna Road’s historic character with revised setback and density standards put in place.

The new zoning guidelines approved on second reading created a new Agricultural Residential Estate Innovative Project district, allowing developers to build single-family homes on lots as small as 2 acres if the average density remains one home per 3 acres. The previous agricultural residential estate zoning required a minimum lot size of 3 acres for each home.

Along with the new acreage regulations, the new AR-IP district requires owners to configure any developable lot abutting Old Smyrna Road to preserve a 100-foot backyard setback from the roadway. The regulations previously required only a 75-foot setback for backyards.

The greater setback requirement for backyards is offset by reduced front yard setback from 175 to 100 feet and side yard setbacks from 50 to 30 feet.

City Manager Kirk Bednar told the commission the regulations arose after the rezoning of 71 acres on Old Smyrna Road in March for a development called Harlan. The new district helps codify an alternative regulation aimed at balancing open space preservation while enabling development, he said.

“This came about after the rezoning of the Mick property in a desire to provide an option for properties along Old Smyrna Road that are currently [agricultural residential], which requires 3 acres per lot. ... It is within the spirit of the AR in terms of density, but we think a little bit more creative subdivision layout and a little more buffer on the Old Smyrna Road corridor would be the benefit of this ordinance," Bednar said at the meeting.

A total of 38 parcels are zoned as agricultural residential estate along the Old Smyrna Road corridor with a total area of more than 353 acres, according to a report by the Brentwood Planning and Codes Department.

The traditional agricultural residential zoning district was originally established and assigned to the eastern portion of town, according to the zoning map from 1973. It was meant to provide additional green space along arterial streets within the city, but over the years the amount of zoned acreage has dropped amid greater development, according to city officials.