D.C. Mayor Vincent C. Gray (D) is rejecting a proposal to shut down a portion of I-395 for more than a year so that a major development project can be completed more quickly.

“Closing 395 is a non-starter for Mayor Gray,” his spokeswoman Doxie McCoy said in an e-mail Tuesday morning.

Meanwhile, Mayor-elect Muriel E. Bowser (D) also spoke against the idea at a news conference Tuesday where she announced the appointment of Alexandria City Manager Rashad Young as her city administrator. “I can’t imagine closing 395. The Young family just came on 395 to get here, and I’m pretty sure they can’t imagine closing it, either,” Bowser said.

At the request of the D.C. Department of Transportation, the Federal Highway Administration has been reviewing the request to close nearly a mile of the freeway, from D Street to New York Avenue NW. The federal agency determined that a lengthy study is needed before making a decision on the request.

New York-based Property Group Partners, the developer of the Capitol Crossing project, says that if the highway is closed for 15 to 18 months it could cut in half the construction time of a $200 million deck over the freeway’s entrance. That platform would create three new city blocks and support the company’s mixed-use 2.2 million-square-foot development.

McCoy said the the outgoing mayor has appointed the city administrator to work with DDOT on the issue. She said the District will continue conversations with FHWA over closing an off ramp to allow the construction.

“However, upon reviewing the matter, [Gray] has made his views very clear —we will not be closing 395 and the administration will inform the feds of that.”

Read our latest story about the FHWA’s response to DDOT’s request here, and the original story about the proposal here.

Mike DeBonis contributed to this report.