Now we know the price tag to keep California public transit agencies from going over a “fiscal cliff” — $5.15 billion over five years.

As part of a budget proposal being unveiled today in the state Senate, transit agency officials and their supporters in the Legislature are seeking “bridge funding” for transit systems throughout the state, some of whom are struggling to recover ridership after the pandemic.

The proposal is being championed by Sen. Scott Wiener, a Democrat from San Francisco, who said that without the state cash, BART and other big-city transit systems will have to make drastic service cuts.

The California Transit Association, which says the plan was created by 15 member agencies, says the $5.15 billion over five years for transit operations can come from a mix of funding sources that already support transit:

• $1.35 billion additional funds from the diesel fuel tax
• $2.5 billion from unallocated cap-and-trade revenue
• $300 million from transit development projects
• $1 billion from future funding for operations

The association and Wiener’s office say the budget request will only require a $213 million reduction to General Fund revenue in the next fiscal year, and pledged to address safety and cleanliness concerns and to continue work on accountability.

Michael Pimentel, transit association executive director, said,: “We recognized the importance of putting forward a request that could enjoy broad-based buy-in not only from the transit agencies, but we hope also by the Legislature and the administration.”

Wiener, meanwhile, said that the bridge funding would help transit agencies preserve services until the dust settles “more significantly” from declining ridership and changing commuting .

“As we look over the next few years at what adjustments need to be made, let’s do that from a position of fiscal strength and not fiscal chaos,” he said.