California had its “Carmageddon,” complete with sequel. Now, New York could be staring at its own potential transportation disaster.

Officials at the Port Authority of New York and New Jersey were hoping for the best Friday as they announced plans to close three of four lanes on the heavily traveled upper deck of the George Washington Bridge to replace sections of the steel beams that support the roadway.

The work is expected to last through the end of the year and will be performed during overnight hours — not that that will be any comfort to the estimated 20,000 vehicles that cross the span during those hours on weeknights, or the 50,000 that cross on weekend nights.

The bridge has two levels: Trucks are restricted to the upper level, which has four lanes in each direction. The lower level has three lanes in each direction and is not part of the current repair project. Crews will cut, remove and replace more than 600 deck panels — steel topped with asphalt — using two large cranes.

Delays of 45 to 60 minutes are expected, but that could be an optimistic assessment. A test run two weeks ago produced 90-minute-delays, albeit with no public notification, said Port Authority tunnels, bridges and terminals director Cedrick Fulton.

“There are going to be delays, no question about it,” Fulton said. “We’re trying to communicate with the public and urge them to change their driving habits. We’re trying to push as many cars as possible down (to the lower level).”

About 300,000 vehicles per day cross the 82-year-old span, which carries Interstate 95 from northern New Jersey across upper Manhattan and northeast into Connecticut. The upper deck opened in 1931, and the lower deck was added in 1962.

About 7 percent of those vehicles travel in the overnight hours during the week and would be affected by the lane closures, Port Authority officials said Friday. That number rises to 17 percent on weekend nights.

The $82 million repair will replace the steel beams underlying the upper deck roadway, which were last replaced in the late 1970s. They were designed to have a 20-year life span, but tests every two years showed they had maintained their integrity, Fulton said. But in recent years, according to bridge chief structural engineer Bernard Yostpille, small cracks had begun to crop up with greater frequency, leading to increasing repairs. The bridge was never in danger from the cracks, said Andrea Giorgi Bocker, engineer of construction for the bridge.

The repairs are being funded by phased-in toll increases implemented in 2011 that will ultimately raise cash tolls from $8 to $15.

Fulton said one concern is that some motorists won’t take the warnings seriously because a project last year to shore up a structure on the New York side of the bridge led to far shorter delays than were expected.

Two years ago, a weekend-long closure of a portion of Interstate 405 in Los Angeles was dubbed “Carmageddon” but didn’t produce anything resembling the epic traffic jams that many feared. Another weekend closure last fall didn’t produce “Carmageddon II,” as many motorists stayed off the road.

The George Washington Bridge work is to begin Monday at 11 p.m. in the westbound lanes and will shift to the eastbound lanes the following Monday. The Port Authority plans to extend the hours gradually until the closures last from 10 p.m. to 5 a.m. on weeknights and 11 p.m. to 9 a.m. on weekends.

Work schedules also will be tailored around the New York Yankees’ home games in the Bronx, Port Authority officials said.

(AP)