The rupture prompted city crews to close the eastbound lanes. That tied the afternoon commute in knots and left many people stuck in traffic for more than an hour to travel the six miles from 'Ainakoa Avenue to Hawai'i Kai.

Judi Kern, a Hawai'i Kai resident who was heading home late from work, knew about the sewer line break but didn't expect that she'd run into bumper-to-bumper traffic at 9 last night.

"Before I even got to Kahala Mall, I had to hit the brakes," Kern said. "It's terrible. What a nightmare."

Much of the the tie-up occurred because three lanes of eastbound traffic were merged into two, then contraflowed onto the townbound lanes at the area of the break near Niu Valley Shopping Center, said police Sgt. Patrice Gionson.

Townbound traffic was detoured from Kalaniana'ole Highway through Niu Valley on East Halema'uma'u Street.

"The mauka-most lanes had to remain closed because the road swelled up and we had to assess if the road would fall in," Gionson said. "We didn't want to take a chance."

The ruptured pipe stretches from the Niu Valley wastewater pumping station on the mauka side of Kalaniana'ole Highway to the makai side for about 75 yards, said city spokesman Mark Matsunaga. Crews will either have to replace the pipe or install a plastic liner, he said. The city believes the pipe ruptured because of corrosion, Matsunaga said.

This morning's townbound commute will be only two lanes in the Niu area. But once past West Halema'uma'u it will be its normal four lanes: three lanes plus one contraflow lane for car-poolers.

The ruptured line spewed an unknown amount of untreated sewage into the storm drains that lead to the ocean, Matsunaga said. Warning signs were posted and the public is advised to avoid affected areas.

Repair crews were scheduled to work throughout the night and at least all day today, Matsunaga said. Last night crews pumped sewage from the broken pipe into trucks, which deposited it into a sewer access point at Wailupe Beach Park.

The pipe that broke is the same one that ruptured on Feb. 2, spilling an estimated 2,025 gallons of untreated wastewater into storm drains that lead to the ocean, Matsunaga said. That same sewer main was also repaired in 2001, Matsunaga said.