SAN DIEGO -- Balboa Park could soon be expanding over Interstate 5 through a wide bridge that can be placed on top of the highway.

Four years ago, the San Diego City Council approved plans to place a lid over I-5 in several locations, including between 3rd and 8th avenues near Tweet Street Park and between Market and J streets.

San Diego has a lid over Interstate 15 between Orange and Polk avenues, where Teralta Neighborhood Park stands. Cities such as San Francisco, Atlanta and Cincinnati have done similar projects.

Currently, 35,000 people live in downtown San Diego, and the city is making room for 60,000 more. Gary Smith, president of the San Diego Downtown Residents Group, said there is not enough open space for that kind of density.

"We have woefully few parks downtown for the number of residents," said Smith.

The lids could create several new acres of new park land or land to build on. Four lids near Tweet Street Park on Date Street would reconnect downtown with Balboa Park. Tweet Street Park used to be a part of Balboa Park until Caltrans constructed I-5 and cut through the middle of the park. The lids would reunite the two parks once again.

"It could be expansions for the museums, it could be parks, it could be basketball courts," Smith said. "It can be anything your imagination could create that would go over there."

Earlier, the San Diego Chargers were investigating constructing a lid so they could build a football stadium on top. Chargers Special Counsel Mark Fabiani told 10News that team representatives met with the New York Jets while the Jets were considering its own new stadium. The Jets were considering building their stadium on top of a rail yard.

Then the Chargers decided it would be too expensive to build the infrastructure, which Fabiani estimated would cost $250 million, and that does not include $1 billion to build the actual stadium.

Despite the price tags, Smith said the lids may be cheaper than buying land. Building new property with a lid would cost about $385 per square foot, while buying old property downtown would cost about $600 per square foot.

"So if you want to build something, especially of a public nature like a park or a new museum, building over the freeway makes perfect sense," Smith said.

The lid that would connect Tweet Street Park with Balboa Park would cost about $200 million.

It is among one of the projects envisioned by the Center City Development Corporation, which total about $1.5 billion.

The CCDC has only about $380 million left in its funds, but the San Diego City Council will consider the raising CCDC's spending limit in June, giving the CCDC more property tax revenue and allow them to finish their projects and pave the way for a Chargers stadium in East Village.