Much is riding on today’s primary election, especially in the three-way race for Hono­lulu mayor, which some consider a referendum on the city’s rail project.

After facing a last-minute shortage of volunteers and changes in voting sites that will affect 1 in 3 voters, state election officials proclaimed themselves ready for the task of ensuring an election without glitches today.

"We’re prepared," Office of Elections spokes­man Rex Qui­dilla said Friday.

The mayoral contest will be decided today if Mayor Peter Carlisle, former city Managing Director Kirk Caldwell or former Gov. Ben Caye­tano receives a majority of the vote. If not, the top two vote-getters face off in the Nov. 6 general election.

Former Mayor Mufi Hannemann faces a tough race against City Councilwoman Tulsi Gabbard in their bid to be the Demo­cratic nominee for the 2nd Congressional District, which includes rural Oahu and the neighbor islands. The two big-name contenders are vying for the seat held by Rep. Mazie Hirono.

Hirono is in her own race against former U.S. Rep. Ed Case in the Demo­cratic primary for the seat of U.S. Sen. Daniel Akaka, who is retiring. Three other Demo­crats are in the primary. Former Gov. Linda Lingle is the leading candidate in the five-person Republican primary.

Because of redistricting, voters in several areas today will be choosing between familiar names who are running against one another.

The Democratic primary contenders for the state Senate 11th District seat covering Makiki, Tantalus and Manoa, for example, include two longtime state legislators.

State Sens. Carol Fuku­­naga (D, Lower Makiki-Punchbowl) and Brian Tani­gu­­chi (D, Moiliili-Manoa) were pitted against each other after a three-judge panel of the U.S. District Court in Hono­­lulu in May allowed the new reapportionment and redistricting plan to proceed.

Two state House races also have incumbents facing each other: Reps. Heather Giu­gni and K. Mark Takai in the 33rd District (Halawa-Aiea-Newtown) and Reps. Pono Chong and Jessica Wooley in the 48th District (Kaha­luu-Ahui­manu-Kane­ohe).

Meanwhile, one state Senate race and seven state House races have no incumbent, largely due to redistricting. Those eight wide-open races attracted a total of 32 candidates.

Quidilla urged voters to check the yellow polling place postcards mailed in recent weeks to make sure they show up at the right polling place. Voters also need to bring photo identification, which will "make the process simpler," he said. "It speeds things up."

People who are still unsure where they need to vote can find their voting site by using the Office of Elections’ online polling place locator at elections2. hawaii.gov/ppl.

Quidilla also expressed confidence in Hawaii island’s ability to efficiently process ballots today after weeks of criticism aimed at Hawaii County Clerk Jamae Kawa­­uchi, who was criticized for shutting down the elections office on two days and changing procedure for absentee voting. Two employees, reportedly the acting election administrator and another election staffer, also are out sick until after the primary election, and a temporary worker quit Wednesday.

"We’ve been reassured by the Big Island county clerk that they’re prepared and ready," Qui­dilla said.

Election officials on Oahu earlier this week found themselves about 300 volunteers short to staff 142 polling sites on Oahu. About 170 new volunteers showed up at an orientation on Wednesday, and Qui­dilla said there are enough volunteers to run a smooth election.

In all, elections officials will rely on 3,100 volunteers across the islands to help staff 233 voting sites.

Polls will remain open from 7 a.m. to 6 p.m. Anyone in line at 6 p.m. will be allowed to vote, Qui­dilla said.

As of Thursday more than 90,300 Oahu voters had returned their mail-in absentee ballots or came in early to vote, according to the Hono­lulu city clerk’s office.

Out of more than 102,637 absentee ballots that were mailed, 75 percent had been returned by Thursday. Another 12,941 people voted early at one of the three walk-in voting sites on Oahu. Those sites closed Thursday.