Los Angeles ? Southern Californians appeared Saturday to be willing to make the ultimate sacrifice to avoid the dreaded “Carmageddon” — leaving their cars in the garage.

Unusually light traffic flowed freely through the nation’s second-largest city despite fears of epic traffic jams spawned by the 53-hour shutdown of a 10-mile stretch of one of the region’s most critical freeways.

Authorities closed the segment of Interstate 405 on the western side of the metropolis to allow partial demolition of a bridge, warning motorists to stay off the roads or plan alternate routes.

Officials were optimistic that the public far and wide had gotten the message, though there was some concern that the lack of gridlock would make the public complacent and that drivers would get behind the wheel before the freeway’s scheduled reopening early Monday.

“We hope they still listen to what we’re saying and not go out and try to drive through this area, because it is going to be congested if people do that,” said Mike Miles, a district director of the California Department of Transportation, known as Caltrans.

Citizens clearly embraced the warnings, leaving neighborhood streets clear near the closure.

“It’s been one of the most quiet Saturdays I’ve seen in forever,” said Steven Ramada, who had expected to hear lots of cars honking in front of his Sherman Oaks home but instead only heard news helicopters.

“Everyone’s calling this Carmageddon weekend, but it feels like copter-geddon over where we live,” he said.

Not everyone was cooperating, though.

California Highway Patrol Officer Charmaine Fajardo said a 74-year-old man was arrested for jogging on the closed freeway after police told him he couldn’t do so, and one or more bicyclists also were intercepted on the route. Fajardo said officers now have orders to arrest anyone trying to enter the shuttered freeway.

Additionally, a suspected drunken driver was arrested after going around barricades to enter the freeway, Fajardo said.

Progress on demolition of the half-century-old Mulholland Bridge was said to be good. Powerful machines with long booms hammered away at the south side of the span, which is being removed to allow the interstate to be widened. The plan is to leave the north-side lanes standing until the south side is rebuilt.

Gail Standish, 47, peddled from Beverly Hills with her bicycling club to a 405 overlook a quarter-mile from the closed span.

“Everybody’s calling this weekend Carmageddon, but seeing the freeway empty it feels more post-apocalyptic,” Standish said.

Authorities looking at the potential impacts of the $1 billion interstate project spent months giving the public dire warnings. The event got its name when Los Angeles County Supervisor Zev Yaroslavsky told an early June press conference that “this doesn’t need to be a Carmageddon” if people avoided driving.

Although no major delays related to the closure had occurred by midafternoon, a major test of was likely in the evening when Major League Soccer’s Los Angeles Galaxy, featuring David Beckam, is scheduled to play Spanish heavyweight Real Madrid at Memorial Coliseum south of downtown.