County election officials are predicting a 45 percent turnout for Tuesday's ballot question asking voters whether they're willing to temporarily add a penny to the current sales-tax rate to put a dent in the state revenue shortfall.

The increase, which would boost the state sales-tax rate from 5.6 cents to 6.6 cents on the dollar, is expected to generate roughly $1 billion annually to help shore up education, health care and public safety.

With local taxes added on, Tucsonans would pay 9.1 cents. That means if you bought $100 worth of taxable goods, the taxes would add up to $9.10 instead of the current $8.10.

The tax would automatically expire after three years.

Typically, special elections attract a much smaller voter turnout than the fall general election.

In 2004, about 22 percent of local voters showed up to weigh in on a series of bond questions. And the 2006 election on the regional transportation plan brought out 26 percent of voters.

Statewide elections don't fare much better typically. While we haven't had a statewide special election in May since 1927, the last statewide special election took place in 1980, when nearly 30 percent of voters took a stand on capping property-tax rate increases.

But this is the first special election testing the impact of the permanent early-voting list.

And already, of the roughly 470,000 voters eligible to vote in this election, the county has already received 110,000 early ballots back. That's nearly a 24 percent turnout before the polls even open.

County Elections Director Brad Nelson reminds voters to double-check their polling locations, since many were consolidated. Voters received notice last weekend on a yellow postcard advising them of their polling locations. For those who tossed it or missed it for some reason, contact the Pima County Recorder's Office.

Nelson also said that with so many voting by mail for the first time, there may be some confusion about the process. "It's not like your tax returns. Postmarks don't count." If elections officials don't have those ballots by Tuesday when the polls close, they won't count. His advice? Take it to any polling place in Pima County and drop it off.

Polls are open from 6 a.m. to 7 p.m.

Voters are also required to show proof of identity at the polling place.

Voters may present one of the following photo identifications: a valid Arizona driver's license or non-operating identification, a tribal enrollment card or other form of tribal identification, or a valid U.S. federal, state or local government-issued identification.

Without photos, the office will take two forms of identification showing a name and address, including utility bills or bank statements dated within 90 days of the election, a property-tax statement and a valid Arizona vehicle registration.

For more information on identification or poll locations, call the Pima County Recorder's office at 740-4330.

Contact reporter Rhonda Bodfield at 573-4243 or