But officials warned the real test was likely to begin around midday, after the country's second-largest city fully awakened.
"So far we're still Saturday morning light," said Mike Miles, a California Department of Transportation district director. "We don't know if that's just because it's Saturday morning, or if in fact motorists are listening to the message that has been put out about not driving this weekend."
He said traffic was expected to pick up as the day progressed.
Ramps to the normally clogged Interstate 405 were shut down Friday evening before the entire roadway was closed at midnight, setting the stage for a 53-hour bridge demolition project that will test whether this car-dependent city can change its driving habits for a weekend.
The bridge work attracted onlookers, many of whom cycled to a parking lot that overlooks the 405 about a quarter-mile from the span.
"Everybody's calling this weekend 'Carmageddon,' but seeing the freeway empty it feels more post-apocalyptic," said Gail Standish, 47, who peddled from Beverly Hills with her bicycling club.
For weeks, authorities have urged residents to avoid getting in their cars, lest they trigger Carmageddon.
Such an event could back up vehicles from the 405 — locals like to joke that its name is shorthand for "traffic that moves no faster than 4 or 5 miles an hour" — to surface streets and other freeways, causing a domino effect that could paralyze much of Los Angeles.
Saturday morning, light traffic whizzed across the region's others highways, and no major delays were reported.
"The work is progressing, traffic is cooperating, and it's moving freely this morning," Miles said.
With warnings having been broadcast through television, radio, social media and flashing freeway signs as far away as San Francisco, many of the city's nearly 4 million residents appeared ready to stay off the roads.
Crews systematically began closing on- and off-ramps beginning at 7 p.m. Friday then began lane closures at 10 p.m., before the entire 10-mile section that runs through the Sepulveda Pass was closed at midnight.
Evening rush-hour traffic was light in the hours before the shutdown. Motorists took to Twitter to marvel at the rare sight of traffic maps showing a sea of green, indicating that traffic was flowing.
"Carmageddon? More like carmaheaven. No traffic in L.A.," tweeted Chip Dorsh, who said he breezed through a canyon road to get from his job in Culver City to the San Fernando Valley.
"When I left work, it was like a no man's land," Dorsh later told The Associated Press.
Mayor Antonio Villaraigosa said he thinks traffic will move smoothly if motorists take advice and stay close to home throughout the weekend.
"We can either say we survived Carmageddon or we survived the Carmageddon hype," he said.
If people listen, there will be no shortage of staycation activities or adventures awaiting them.
They can snag free cotton candy at the Santa Monica Pier or drop in on Michael Jackson's dermatologist for 25-percent-off Botox injections so that frazzled commuters won't look quite so frazzled.
Those who do want that real road warrior look might consider swinging by T-Man's Tattoos (located just off the 405) in the San Fernando Valley.
"If you come on in and mention you're in town because you're stuck from Carmageddon, you can get 15 percent off tattoos and piercings," proprietor Howard Teman said.
A few planned to take discounted helicopter rides over the empty stretch of the 405, several dozen others have $4 to $5 tickets to board special JetBlue flights between Long Beach Airport and Bob Hope Airport in Burbank. The airline, seizing on the national buzz about Carmageddon, offered the deal this week by calling the short, 20- to 30-minute flights a "planepool" between the San Fernando Valley and the coastal city.
Tickets sold out within three hours.
The flights inspired a group of cyclists to challenge JetBlue to a race. Members of the Wolfpack Hustle planned to peddle on a roughly 40-mile route starting near the Burbank airport to see whether they or a JetBlue passenger will reach Long Beach first.
Cycling advocates said they hope to show that gridlock can be avoided without using a car or plane.
"Everyone's freaking out about car traffic around the 405, bicycling represents a very viable alternative," cyclist Gary Kavanagh said.
Meanwhile, construction crews were working feverishly to take down half of the 50-year-old Mulholland Bridge as part of a $1 billion freeway-widening project.
Extra police, fire and medical personnel were on hand to ensure that everything goes smoothly. Or, if it doesn't, to ensure they are prepared to handle any emergency.
The city fire department put two dozen additional engines, fire companies and ambulances into service, placing them in neighborhoods that firefighters might have a hard time getting to from jammed roadways.
Much of the section of freeway that is being shut down winds through a hillside pass near Beverly Hills and other communities that are susceptible to brushfires.
Wildfire season, however, hasn't reached its peak yet, fire officials said. Besides, this weekend's expected humid weather should further reduce the threat of a fire.
The UCLA Health System, which runs the huge Santa Monica-UCLA Medical Center located near the 405, was putting its weekend staff in dorm rooms and hotels to ensure they don't run late to work. Three helicopter companies were on standby to transport patients and human organs in case of emergency procedures.
For those who do have to drive, a Cedars-Sinai Medical Center psychiatrist was offering advice on how to keep calm and stay safe.
Among Dr. Waguih William IsHak's advice: avoid road rage at all costs, apologize profusely to anyone you accidentally cut off in traffic, be sure to leave for your destination with a full tank of gas and a cell phone.
Or, better yet, authorities say, stay at home.
"If everyone heeds our advice, this whole weekend will be in our rear view mirror and everybody will be fine," Los Angeles County Supervisor Zev Yaroslavsky said.
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AP writers John Rogers and John Antczak contributed to this report.
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