There simply isn’t enough money to adequately maintain California’s crumbling highways and bridges, Gov. Jerry Brown’s revised budget proposal acknowledges.

Brown’s proposal would boost general-fund spending on transportation from $200 million in the current year to $261 million in 2015-15, a 30.5 percent increase. There’s also $8.86 billion in special funds and $2.1 billion in bond funds earmarked for transportation, bringing next year’s total to about $11.2 billion.

But the past decade’s spending was mostly on reducing traffic jams, allowing for faster shipping of goods, funding local streets and roads, and transit facilities, the proposal notes. Meanwhile, highway repair and maintenance — though crucial to California’s economy — has “largely been overlooked,” the budget plan acknowledges.

Current gas-tax revenue covers only about $2.3 billion of the state’s $8 billion in annual highway repair needs, Brown’s plan notes, and so there’s $5.7 billion each year in deferred maintenance.

And gas-tax revenue is decreasing as cars become more fuel efficient and some drivers switch to hybrids or electric cars — good for the environment, but bad for highways. “While the state is accelerating the pilot program to explore a potential mileage-based revenue collection system, or Road Usage Charge, implementation of a broader statewide program is not likely for a number of years,” the plan says.

So a transportation infrastructure priorities work group will keep meeting to triage the state’s most pressing highway needs, and Brown’s administration is working with lawmakers to develop a pay-as-you-go funding package by the end of this year.

On the brighter side, significant proceeds from the state’s cap-and-trade program to reduce greenhouse-gas emissions went to clean-transportation and mass-transit uses starting in the current budget year.

Brown’s revised transportation budget for next year provides $1.6 billion from these revenues, including $500 million for the controversial high-speed rail system that Brown ardently supports.

It also includes $100 million for transit operations in the Low Carbon Transit Operations Program, and $265 million for rail and transit in the Transit and Intercity Rail Capital Program. Another $400 million goes to the Affordable Housing and Sustainable Communities Program, which funds land-use, housing, transportation, and land-preservation projects to support infill and compact development. And $350 million goes to the Air Resources Board’s clean transportation programs.

Josh Richman covers politics. Follow him at Twitter.com/Josh_Richman. Read the Political Blotter at IBAbuzz.com/politics.