Updated, 5:45 p.m. Wednesday

Gov. Jerry Brown and Democratic leaders of the state Legislature unveiled a plan Wednesday to raise $52.4 billion over the next decade to pay for a massive program of rebuilding California's highways and bridges and improving public transit.

The plan would be paid for with a combination of revenue measures: an increase in the state's excise tax on gasoline from 28 cents to 40 cents a gallon, increased vehicle registration fees and a new $100 annual charge on emission-free vehicles.

"Let's be clear -- our roads suck," said Assembly Speaker Anthony Rendon, a Los Angeles Democrat, one of those who unveiled the plan during a media event on the steps of the State Capitol. "Our bridges are crumbling. Traffic takes time away from our families. ... Potholes take money out of our wallets. Delays cost businesses money and raise prices for consumers."

The plan was embraced by public transportation agencies, who noted that it could provide about $1 billion a year for local and regional transit agencies and $100 million annually for bicycling and pedestrian infrastructure. That infusion of dollars would come as the Trump administration is suggesting killing a major federal grant program for transit.

That guarantee of new transit funding "would have a huge impact," said Rebecca Saltzman, president of the BART board of directors.

"Especially with the uncertainty of federal funds, this would be big for BART and all the transit agencies in the state," Saltzman said.

The new state proposal, still under development as SB 1 by state Sen. Jim Beall, D-San Jose, could also help pay for Caltrain's $2 billion electrification project. The Peninsula rail agency is awaiting word on whether the Trump administration will move forward with a $647 million grant that the U.S. Department of Transportation had approved in January, just days before President Barack Obama left office.

Carl Guardino, CEO of the Silicon Valley Leadership Group and a member of the California Transportation Commission, said Beall's proposal would include funding for relieving congestion in "corridors of significance" throughout the state.

"One of those corridors of significance is Highway 101," Guardino said. "That's not only road improvements on Highway 101, it is improvements like Caltrain electrification. We can't forget that three out of every five passengers on Caltrain are choice riders -- they own cars, but they're choosing to get out of their own cars and ride Caltrain, taking traffic off 101, 280 and all those surface streets."

Brown argued during Wednesday's announcement that the revenue plan, to be backed up by a state constitutional amendment that would require proceeds from revenue measures to be spent on transportation projects, would ensure that the state takes care of its infrastructure needs on a pay-as-you-go basis. Backers say the plan would cost most drivers less than $10 a month.

The plan would require a two-thirds vote in both the Assembly and Senate. That's a goal that's within reach for Democrats, who hold supermajorities in both houses.

But the proposal, coming after years of party-line disagreement over how much the state ought to spend to pay for its estimated $59 billion in deferred highway infrastructure maintenance and how the investment should be paid for, drew an immediate "no" vote from Republicans in the Legislature.

As they have throughout years of negotiations, GOP legislators said that California drivers are paying high gasoline taxes and that the state brings in enough revenue to pay for needed infrastructure fixes and upgrades without increasing levies.

“Our state has become increasingly unaffordable for ordinary Californians," a joint statement from GOP lawmakers said. "We can fix our roads and bridges by simply ensuring that the billions of dollars that drivers are already paying in transportation fees and taxes are actually used for transportation purposes, rather than being swept into the state’s general fund. We strongly urge the Legislature to reject this historic tax hike in favor of our responsible plan that fixes our roads without raising taxes and fees."

California's gasoline taxes -- which in addition to the current 27.8 cent per gallon excise tax, 2.25 percent state sales tax and an 18.4 cent per gallon federal excise tax -- currently total 56.53 cents per gallon. That's the fifth-highest rate in the country, after Pennsylvania, New York, Washington state and Michigan.

However, part of the pinch on the state's transportation finances is due to a large decline in the state excise tax -- from 39.5 cents in 2013-14 to the current 27.8 cents.

Brown dismissed criticism of the revenue plan.

"The only objection is political," he said. "And I think that political objection is pretty weak."

He said "the vast majority" of the $52 billion raised in the plan would go to existing facilities -- and he compared the situation to that of a homeowner.

"What do I say to someone whose roof is leaking?" Brown asked. "Just let it ruin the rug? Let it ruin your nice chairs? No! You gotta fix it. This is life. As grown-ups, we know that things we build wear out and you gotta fix 'em."

Another potential voice of opposition came from progressive transportation advocacy group TransForm.

Joshua Stark, the group's state policy director, said he was troubled by reports that the final bill will exempt trucks from clean-air regulations passed by the California Air Resources Board.

Those rules were passed largely to reduce particulate pollution from diesel engines near the state's biggest ports -- a form of air pollution that is linked to high rates of asthma and other respiratory and circulatory diseases in nearby communities, like West Oakland. The industry has said complying with the rules is prohibitively expensive for many individual operators.

"This is generally a very good package," Stark said. "As an organization committed to sustainable, equitable transportation policy, it's heartening to see senior leadership take up the mantle." But he called the reported trucking exemption "very concerning" and said TransForm would stand with community groups that have fought for the air rules.