The Washington Metropolitan Area Transit Authority signed on to an agreement Tuesday with Gilbane Development Company to develop a residential and retail project at the College Park Metro Station, according to a Metro press release.

The development will include 440 market-rate multi-family units and around 12,000 square feet of retail space. Landscaping and pedestrian safety improvements to the site, located at 7201 River Road, are also included in the project.

“Signing the agreement is a significant milestone in that the project will now happen,” said Ken Ulman, the president of the Terrapin Development Company, which manages real estate ventures on the Route 1 corridor near the University of Maryland.

[Read more: Council has concerns over apartment development near College Park Metro Station]

Ulman said the introduction of both residential and retail space near the Metro is a big part of developing the city’s Discovery District and transforming it into a “walkable, enjoyable place.” Connecting more people to public transit helps the city become more sustainable, he said.

The retail spaces in the development will likely be service-oriented, he said — coffee shops, restaurants and other places “the folks who are going to live in the Gilbane project will like.”

“Maximizing transit-oriented development around Metro stations brings more residences and jobs within walking distance of our stations, which increases ridership and revenue for Metro without increasing costs,” said WMATA Real Estate and Parking Office Managing Director Nina Albert said in a statement.

Metro signing the joint development agreement is a sign “that the area is on the move,” Ulman said. The redevelopment of the site had been attempted three times since the early 2000s before Gilbane got on board.

[Read more: Prince George’s County allocates funds for affordable housing initiatives, Purple Line]

Gilbane was selected to be the developer of the College Park Station in mid-2016, Ulman said, and has since been working with the city, county and WMATA to get the necessary approval to start the project.

“It really just takes the brakes off us because we can just … move forward with the rest of the design for the project in order to deliver, or really break ground as soon as possible,” said Gilbane Vice President Robert Gilbane.

The joint development agreement was held up for so long because of the complexity of the site, Gilbane said. The station is a future site of the Purple Line, so considerations have to be made to ensure the two projects interact in a safe, complementary way, he said.

Development plans for the Purple Line had not been finalized until recently, so Gilbane had to iron out the details with the Purple Line team, Gilbane said. Once the major issues were addressed, the joint development agreement could go ahead.

“Everyone really has the same goal — it’s just there’s a lot of coordination that needs to take place,” Gilbane said.

Now that WMATA has agreed, the development will occur, but the exact plan is still in formation, and must be reviewed by county and city officials.

College Park Mayor Patrick Wojahn said the city is still involved in the development review process for the site. When Gilbane submits their detailed site plan, the city can choose whether to recommend the county approve the plan.

In October, the council raised concerns that the project would increase noise levels or cause pedestrian safety issues. The county approved Gilbane’s Preliminary Plan of Subdivision in November, subject to conditions that require the company to address the noise and pedestrian safety issues.

Gilbane said the company was planning to submit the project’s detailed site plan later this spring, expecting for the plan to be fully approved early in the fourth quarter of 2018. Construction would begin shortly thereafter.