Los Angeles residents escaped "carmageddon" when contractors finished work on a key stretch of highway 17 hours ahead of schedule at the weekend.
Interstate 405, a main artery through the city, closed at midnight on Friday and reopened at noon on Sunday.
A 10-mile (16km) stretch was shut so workers could demolish a bridge.
Fears of a traffic disaster in the nation's second-largest city did not materialise, in part because residents heeded warnings to stay at home.
"It forced us to enjoy the day instead of jumping in the car and running errands," Stephanie Leto told the Los Angeles Times as she relaxed with a friend, her baby and her dog in Palisades Park in nearby Santa Monica.
The highway was closed to replace half of the 50-year-old Mulholland Drive Bridge, as part of a $1bn (£600m) project to add additional lanes to a bottlenecked segment of the highway.
With a traffic disaster averted, Los Angeles officials now turn their attention to next year, when they will refit the other side of the bridge.
The Los Angeles authorities had recruited celebrities with large Twitter followings to warn residents of the closure, and a Los Angeles county coined the term "carmageddon" to raise awareness.
With the impending chaos from the closure expected to grind traffic to a halt the authorities had warned motorists to stay off the road.
The work began at midnight on Friday, with contractors working around the clock to beat a 0500 local time deadline - or risk a fine of $6,000 (£3,728) for every ten minutes the highway remained closed beyond that.
During the days leading up to the closure, helicopter taxi rides were being sold for $150 to passengers hoping to get to Los Angeles International Airport during the weekend.
Discount airline JetBlue offered a 10-minute flight between Burbank and Long Beach for $4 per ticket.
A group of cyclists raced the flight and won - because the air passengers had to leave the house, check in at the airport, board and get back off the plane.
City officials have been issuing bleak traffic warnings to Southern California residents for weeks, reminiscent of flood and wildfire warnings.
Some transport experts compared the shutdown to other large planned events in the region, like the 1984 summer Olympics, Los Angeles Lakers championship parades and Michael Jackson's memorial service - events when Los Angeles residents stayed off the roads.
Just like now, "people had advanced notice to get off the roads during the Olympics", said Genevieve Giuliano, a professor of urban planning and policy at University of Southern California.
The city of Los Angeles asked several celebrities, like Tom Hanks and Ashton Kutcher, to warn Los Angeles residents about carmageddon through the micro-blogging website Twitter.
"This weekend, LA! Avoid Carmageddon, Gas-zilla, 405-enstein, Grid-lock-apalooza! STAY HOME. Eat & shop local," Hanks wrote.
Facebook also agreed to direct some 6.6 million Los Angeles area residents to the Metropolitan Transportation Authority's Facebook page for information on avoiding the traffic.