ENCINO (CBSLA.com) — Lane closures on Sepulveda Boulevard due to the installation of a gas pipeline could mean a traffic nightmare between the Westside and the San Fernando Valley.

The closures started about 5 p.m. Sunday as workers began placing the underground pipeline along Sepulveda Boulevard at Skirball Center Drive in the Sepulveda Pass, according to the Southern California Gas Company. The work slows traffic in the Sepulveda Pass and the northbound 405 to a crawl.

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Only one lane will be available on Sepulveda Boulevard in each direction at the top of the Sepulveda Pass Monday and into Tuesday night, according to SoCalGas’ Rosa Maria Santana.

Offramps from the southbound 405 at Skirball Center Drive will be reduced from three lanes to one, Santana said. Traffic may also be restricted on the onramps to the south 405.

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The Gas Company asked West L.A. motorists to use alternate routes, but one of those major alternatives – Topanga Canyon Boulevard – was blocked much of Sunday with fire department vehicles and residents waiting to return from evacuations caused by the Old Fire in the Calabasas area. The boulevard has since been reopened.

For traffic on the 5s, tune in to KNX 1070 NEWSRADIO.

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