Traffic in the Seaport has become so bad that one developer proposed a sky-high transit alternative to ferry visitors to and from South Station. The fate of that project is now in the hands of Boston leaders.

Millennium Partners proposed in 2017 a 2.7M SF development in the Raymond L. Flynn Marine Park. But its location in the Seaport’s eastern edge meant visitors would have to deal with the neighborhood’s crowded bus network. Millennium floated the idea of a $100M aerial gondola network that could shuttle up to 15,000 people daily between South Station and the planned development.

The developer has remained quiet on the Seaport plans, especially the gondola. While the trasit plan isn’t dead, it is out of Millennium Partners’ hands, the Boston Business Journal reports. Millennium is focused on its Winthrop Center development that broke ground last week as well as the land it has in the Seaport, but the gondola will require a full blessing from City Hall.

“From our perspective, it was an idea or a concept that we tested, to see if we thought it was real,” Millennium Partners principal and founding partner Christopher Jeffries told the BBJ. “And when we thought it passed the first test — could it be real? — we then turned everything over to the city.”

The city is embarking on a Seaport transportation study in January that will focus on the best option for improving transit in the neighborhood. The Boston Planning & Development Agency stressed the focus of the study will be on buses.

Critics of the gondola proposal said the city should avoid the privatized system in favor of Bus Rapid Transit and improvements to the existing Silver Line network in the neighborhood.

It is unclear if the gondola proposal will be part of the city’s study, Jeffries told the BBJ.