Jamzilla lane closures on the 405 Freeway begin tonight

Jamzilla is nearly here.

Lane closures on the 405 Freeway start tonight at 10 and are scheduled to remain in place until 6 a.m. Tuesday.

Most or all lanes on the busy northbound side of the freeway will be closed. The shutdowns through the Sepulveda Pass will allow workers to pave and re-stripe the highway where a carpool lane is being added.

Transportation and law enforcement officials are urging drivers to avoid traveling north through West Los Angeles and the Sepulveda Pass for the duration of the closures.

During daytime hours, two northbound lanes will be open, but all five will be closed at night.

Jamzilla is the name transportation officials have given the freeway closure. It recalls the full-freeway weekend closures of 2011 and 2012, which gave workers time and space to demolish the Mulholland Bridge.

The first of those closures gave rise to the apocalyptic term “Carmageddon.” The Southland survived the loss of drive time relatively unscathed.

For Presidents Day weekend, “we wanted to come up with a term that would be like Carmageddon in its ability to influence the public,” said Dave Sotero, a spokesman for the Los Angeles County Metropolitan Transportation Authority, which is managing the $1.1-billion freeway-widening project.

This closure, he said, is similar to Carmageddon but affects only the northbound side. Three of five northbound lanes between Getty Center Drive and Ventura Boulevard will be closed during the day.

They are the three lanes closest to the freeway median, where workers will be paving. The remaining two lanes, Sotero emphasized, will not be able to accommodate the usual 405 traffic, nor will Sepulveda Boulevard be able to handle spillover during the day.

Southbound lanes will be unaffected during the day, but one or two lanes will probably be closed at night, Sotero said.

Metro and the California Department of Transportation are advising motorists to scope out alternate routes and to monitor traffic conditions via Twitter, Facebook, news reports and Metro’s 405 project website.

The 405 typically carries about 300,000 vehicles a day. In a bid to ease its notorious congestion, Metro and Caltrans in 2009 began preliminary work on the final 10-mile leg of a carpool lane through the pass.

In addition to completing the northbound “high-occupancy vehicle” link between Orange County and the San Fernando Valley, the project called for building new on- and offramps, demolishing and rebuilding three bridges, and adding miles of retaining and sound walls.

Officials initially forecast completion of the carpool lane by spring 2013. The timeline was later nudged to December 2013, then to summer 2014.

Sotero said the project team picked Presidents Day weekend because it was the earliest three-day weekend that would enable Kiewit, the contractor, to complete the project this summer.

martha.groves@latimes.com