SAN FRANCISCO (AP) -- Officials in California are bracing for long lines and urging patience as voters cast ballots on "Super Tuesday" in what could be record turnout for a presidential primary election.
A fraction of the 20.7 million registered voters in the heavily Democratic state has already returned ballots in early voting, which started last month. Officials expect the bulk of ballots to be cast Tuesday.
Enthusiasm is high among Democrats eager to elect a candidate they hope can oust President Donald Trump in the fall, and California moved up its primary from June to March so voters could weigh in earlier.
The state has been blanketed by continuous advertising from billionaires Mike Bloomberg and Tom Steyer, who dropped out of the race Saturday after a third-place finish in South Carolina. Sens. Bernie Sanders and Elizabeth Warren and former Vice President Joe Biden are still running for California's 415 pledged Democratic party delegates.
But the primary also coincides with a number of changes aimed at expanding voter participation. Those changes may end up confusing voters or contributing to longer lines.
In casting his ballot at an early voting center last month, Secretary of State Alex Padilla said that election day wait times may be longer than normal given the number of people registered to vote. Voters are also weighing in on congressional races, state legislative seats and a statewide school bond.
"I'm expecting we're going to see an avalanche of ballots on election day, and it's going to take a while to figure out the results," said Kim Alexander, president of the nonpartisan California Voter Foundation.
New this year, Californians will be able to register to vote through 8 p.m. Tuesday at any location where ballots are accepted, which could tie up lines as people fill out paperwork. Results may be delayed because provisional ballots take longer to count.
Also, 15 counties representing more than half the state's voters have replaced traditional neighborhood polling places with a smaller number of multi-purpose vote centers where people can register, vote and take care of other elections business.
The new centers are designed to make voting more convenient, but may confuse people who are accustomed to visiting their local polling place.
Los Angeles County reported several hiccups when it rolled out its vote centers last month. A handful opened late or not at all because equipment didn't arrive in time or workers didn't have correct information to start new touch-screen ballot markers.
Sacramento County will be tripling staff at a voting center at Sacramento State University that saw huge lines in November 2018 as students raced to register at the last minute. Everyone in line by 8 p.m. got to vote, even if that was hours later, spokeswoman Janna Haynes said.
Elections officials have been encouraging people to vote early, in case of problems and to avoid election day mayhem. But voters like to hang on to their ballots, perhaps more so for an election with a wide-open presidential primary.
Voting advocates hope the waits won't discourage voters.
"Overall, California has suffered from long lines a lot less than other states," said Jonathan Stein, head of the voting rights program at Asian Americans Advancing Justice-Asian Law Caucus.
"The long line is unfortunate but ultimately, it's a product of California trying to do the right thing by voters," he said.