An excise tax on gasoline of 17.3 cents per gallon bought by drivers will cease to exist unless it is passed again by the Legislature this year thanks to two measures voters approved in last November's election, The Press-Enterprise of Riverside County reported.

If a solution isn't found, state and local transportation officials will not know what kind of state money to expect for road and transit projects, which could delay some long-sought priorities.

Lawmakers replaced California's 6% sales tax on gasoline with the excise tax last year as part of then-Gov. Arnold Schwarzenegger's state budget, raising roughly the same $1.6 billion each year.

Schwarzenegger in past budgets used state sales tax revenues from gas to buttress the General Fund that pays for many state programs. After he was sued by the California Transit Association and lost, Schwarzenegger suggested replacing the sales tax with an excise tax that he could borrow from.

But Proposition 26, which voters passed last year, requires all tax changes approved in 2010 to pass with a two-thirds vote within a year. Retroactively, officials believe they now need to pass the gas-tax swap again, or else it will be null and void in November.