Nearly 3 in 4 Californians want more money spent on filling potholes and repaving freeways and city streets, but they have little appetite for paying the bill.

A new Field Poll found voters are lukewarm to hiking the gas tax and clearly opposed to charging motorists based on the number of miles they drive — an idea being studied to make sure the growing number of electric vehicle drivers pay their share.

The poll results released Friday revealed once again the squeeze transportation planners face in trying to ease one of California motorists’ biggest concerns as roads built as long as 70 years ago are falling apart and gas tax revenues have been dropping for a decade. The need is obvious to almost everyone behind the wheel, as the backlog to fix the Golden State’s roads and bridges has climbed to $59 billion.

“The public is very supportive on spending more for roads,” said Field Poll director Mark DiCamillo. “But how you pay for it has trouble gaining that support.”

A 10 cent-per-gallon hike in the gas tax would be the most palatable solution, according to the Field Poll, but only 48 percent of voters polled said they would support that idea, while 49 percent opposed it. While Democrats were more open to the gas-tax hike — 63 percent — Republicans were solidly opposed. Any tax hike would require a two-thirds majority in the Legislature.

The poll found 55 percent of those surveyed are dead set against building more toll roads like those common in Southern California.

And Californians are even more turned-off by an idea to charge drivers a mileage fee to make up the drop in gas tax revenues as cars become more efficient, forcing EV drivers to pony up. In all, 66 percent of those polled were against the idea, including 59 percent of Democrats.

“That is an invasion of my privacy,” said Justine Issavi, a Stanford graduate student troubled by the idea of a gadget that would track the miles she drives. “Not only will it track my mileage, but how do I know it won’t track my movements too? Another invasion of my privacy. That is problematic enough with all the electronic devices I already use voluntarily.”

On the other hand, Kristina Teves, an actress from San Ramon, said electronic monitoring would be the fairest way to make sure that all drivers — including ones who can afford Teslas — would be held responsible for funding.

“I’d hope the electronic system would help the government determine not only how much to put into road maintenance, but how much in funding to aim back into specific communities,” she said. “That system would help them allocate all that money more fairly.”

California’s high gas taxes were often cited by many opposed to paying more at the pump, with 3 in 4 voters saying we already pay too much. State drivers now pay 63.79 cents a gallon in federal and state gas taxes, second behind only to Pennsylvania.

However, California’s tax will drop by 6 cents on July 1 to 57.79 cents. The national average is 48.23 cents.

Dan O’Neal, of San Jose, who recently returned from a trip to Washington and Oregon, said the problem back home is obvious.

“I had forgotten what a well-maintained road system exists outside of this state,” he said after not hitting “a single pothole or damaged road surface for a whole week in over 2,000 miles of driving.”

A dime tax would be OK with him “provided it was only spent to repair and maintain road surfaces.”

The Metropolitan Transportation Commission in Oakland has had the authority to place a dime-a-gallon tax on the ballot in the nine Bay Area counties for nearly two decades. But the agency’s polls have shown only about a third of voters would support the measure, so the MTC has never taken the idea to the public.

Raising the gas tax has been approved in several states since Jan. 1, the most recent on Tuesday in Iowa, with a dime hike. Maryland, Virginia and Pennsylvania have raised their gas taxes by 3 to 9 cents, and Minnesota is debating a 21-cent hike.

Some members of Congress also have voiced support for raising a federal gas tax that has not been increased since 1993.

Bay Area voters have shown a willingness to pay for road work in other, less divisive ways. Three years ago, they approved a $10 hike in vehicle registration fees, and Alameda County voters in November approved a new half-cent sales tax that will set aside $2.3 billion over the next three decades for local streets. Next year, Santa Clara County will consider a new sales tax that is almost certain to earmark funds for road upgrades, and San Jose may pursue a $400 million bond measure for neighborhood streets.

No surprise, said pollster DiCamillo.

“There are more Democrats in the Bay Area, and Democrats support sales taxes for roads,” he said. “The chances locally are much better here.”

Contact Gary Richards at mrroadshow@mercurynews.com or 408-920-5335. Contact David E. Early at 408-920-5836. Follow him at Twitter.com/DavidEarlySr.