The idea of building an Interstate 71 interchange just south of Alum Creek Reservoir in Delaware County is an old one, but a planned study could give it new life.

The idea of building an Interstate 71 interchange just south of Alum Creek Reservoir in Delaware County is an old one, but a planned study could give it new life.

Robert Riley, chief deputy engineer for Delaware County, said an interchange at Big Walnut Road near the border of Genoa and Orange townships has been a feature of the county's transportation plans since the late 1980s.

The last study of the potential for the interchange, completed in 2009, led county officials to determine the project would be too costly. The study concluded the project would create enough new traffic on I-71 to require construction of new southbound and northbound lanes on the highway.

"It became an $80-million freeway expansion, which Delaware County couldn't fund," Riley said.

The new study, which a yet-to-be-determined consultant will undertake this summer, will examine alternatives that would not require adding lanes to the interstate.

"That could mean ramp meter lights (or) timing traffic signals in such a way that would limit the amount of traffic" accessing I-71 during rush hour, Riley said.

If the study concludes the interchange can be constructed without adding lanes to the highway, Riley said the cost of the project could fall to about $30 million. He said the study should be completed by summer 2016.

While the county's approach to the planned interchange has changed over the past decade, so has the character of the nearby land. Riley said the transformation of the area from rural to largely residential benefits the project's prospects.

"First and foremost, this (planned) interchange really serves a developed area at this point," he said. "This is no longer out in the middle of nowhere."

Officials said they think the project could reduce congestion in the Polaris area in addition to serving residents of the Big Walnut Road area.

Hurdles for the proposal include securing funding and getting final approval from officials in Washington, D.C. Riley said the project cannot move forward without the OK of the Federal Highway Administration.

"It's really not the county's decision or (the Ohio Department of Transportation's), for that matter," he said. "It's a decision made in Washington."

Riley said the FHA can reject the project if federal officials conclude it will degrade the highway's operation and negatively affect interstate commerce and travel.

The county's push to revisit the Big Walnut interchange comes amid an ongoing discussion of another major interchange project within the county.

The county, state and developers have been examining plans to improve I-71's interchange with U.S. Route 36/state Route 37 to serve major commercial projects planned for the Sunbury area. An ODOT study released late last year recommended an $84-million project to build a new interchange 3,700 feet south of the existing interchange.

Riley said the new study will analyze the highway's operation with and without the addition of a new interchange near Sunbury.