LOS ANGELES >> The event that many feared would be the "Carmageddon" of epic traffic jams cruised calmly to a finish Sunday, with bridge work on the Los Angeles roadway completed nearly a full day ahead of schedule and officials reopening a 10-mile stretch of the busy freeway.

Drivers honked their horns and waved from car windows as traffic started moving in all 10 lanes of Interstate 405 just after noon for the first time since being shut down at midnight Friday.

There were no major problems since the freeway was closed, and the biggest worry of all — that the work would spill into the area’s always rough Monday morning commute, was set aside.

Mayor Antonio Villaraigosa praised contractors for working so quickly and thanked city residents for heeding calls to stay off the roads. He also gave credit to news outlets for spreading word about the closure, which had been planned to last for 53 hours.

"We couldn’t have done this without the cooperation of this city," Villaraigosa said.

Crews finished demolition work on the bridge at about 7 a.m., toppling two massive pillars. About 4,000 tons of concrete rubble was expected to be removed over the course of the job.

For weeks, authorities warned people that driving as usual this weekend could trigger what had been hyped as an event that could back up vehicles from the I-405 to surface streets and other freeways, causing a domino effect that could paralyze much of Los Angeles.

Signs warning drivers well in advance about the closure appeared not just near the affected freeway but all over Southern California and as far away as the San Francisco Bay Area.

But the fears of epic traffic jams dissipated with only light weekend traffic.

"It was just so nice. It took me actually less time to get to work than it would have on a normal weekend," said Jenn Tanaguchi, a hairstylist who has to drive from downtown to her job at a salon in Brentwood. "People were telling me that I would have to leave two hours early, that everything would be blocked out. But there were no problems. It was such a nice ride."

Officials said during the closure there were 65 percent fewer automobiles on freeways in the LA metro area, compared with normal weekend traffic.

The California Department of Transportation reopened the freeway in phases. The off-ramps were opened first, then the freeway itself, followed by connectors from other freeways and the on-ramps, the mayor said.

Demolition work previously was expected to be completed by 2 a.m. Monday, followed by cleanup and reopening of the freeway at 5 a.m., with on-ramps and connectors all reopened by an hour later.

The reopening attracted a few onlookers to a parking lot above the freeway. Albert Hill, 47, a Westwood resident, brought his three-year-old son to take photos of the empty lanes and the first cars to return to the 405.

"This is a historic moment for me. I’ve lived here my whole life, so to see it closed down, I thought it could never happen," Hill said. "This Carmageddon thing was the best weekend ever in LA. There was no traffic anywhere. I couldn’t believe it. I think we should have Carmageddon every weekend."

Project contractor Kiewit Infrastructure West could have been fined a $72,000 an hour for delay in getting the freeway reopened, according to the city’s Metropolitan Transportation Authority.

Instead Kiewit will receive an extra $300,000 for finishing early. The project gets to save $400,000 — even with the Kiewit bonus — since paying workers for an additional 12 hour shift would have cost $700,000.

Powerful machines with long booms hammered away at the south side of the half-century-old Mulholland Bridge, which was removed to allow construction of an additional freeway lane. The plan is to leave the north-side lanes standing until the south side is rebuilt.

Another closure will be required in about 11 months to demolish the rest. Officials said they were hopeful that the future shutdown would run just as smoothly as this one.

Ira Vitug, 27, who works for a mortgage company in Calabasas, is already anxious for phase two, and for the entire project to be done. "Glad it’s over and ready for the next," she said. "Bring it on!"

The project picked up its apocalyptic name when Los Angeles County Supervisor Zev Yaroslavsky said at an early June news conference that "this doesn’t need to be a Carmageddon" if people avoided driving.

On Sunday, Yaroslavsky jokingly dismissed the phrase that took on a life of its own. "Carmageddon, Shmarmageddon!" he declared.

"I think people in L.A. have learned that you can get along without having to take long car rides on a weekend," the supervisor said.

The mayor agreed.

"I think everyone has realized that we can get out of our cars once in a while and survive," Villaraigosa said.

He added that he loved hearing reports of people venturing out in their neighborhoods on foot, meeting neighbors, and making time for family dinners and barbecues.

The drumbeat of warnings about the weekend triggered an instant industry of businesses trying to capitalize. JetBlue offered special flights from Burbank in the San Fernando Valley to Long Beach, with seats for the short hop costing just $4 or $5.

Some trespassers crept onto the 405 during the shutdown. Officials report a bicyclist made it onto the road before getting escorted off by police, a man was cited for driving on the roadway, several people were found putting up a large sign, and a man was caught scaling a perimeter fence.

Many mocked the frenzied language surrounding the closure, especially on Twitter, where Hollywood’s comedians had at their hometown.

"How’s everyone coping with this terrifying apocalyptic nightmare of having to … oh my god … stay home with your family?!!!" Bill Maher wrote.

Albert Brooks was more philosophical.

"If we would close the freeways every weekend," he tweeted, "we would have a great society."

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Associated Press Writer Andrew Dalton contributed to this story.