Motorists in Los Angeles are preparing for what's being billed "Carmageddon II" this weekend.

A bridge demolition project will shut down both directions of the main traffic artery between west Los Angeles and the San Fernando valley.

On- and off-ramps on the San Diego Freeway in the Sepulveda Pass will begin being blocked around 7 p.m. Friday night.

Freeway lanes will be blocked beginning around 10 p.m.

At midnight, the northbound freeway will be completely closed between the Santa Monica and Ventura freeways.

Southbound lanes will be closed between the Ventura Freeway and Getty Center Drive. The closure, which will enable crews to demolish the north half of the Mulholland Bridge over the freeway, is expected to continue until 5 a.m. Monday.

The demolition and reconstruction of the Mulholland Bridge is part of the billion-dollar Sepulveda Pass improvement project that is adding a 10-mile northbound carpool lane and making other upgrades along the route.

The project is expected to be completed next year.

The Los Angeles Fire Department will have more firefighters and paramedics working on the Westside for "Carmageddon II" this weekend.

The extra personnel will include motorcycle teams capable of weaving through gridlocked traffic in an emergency.

The motorcycle teams, which include two firefighter/EMTs, will be stationed on both sides of the freeway.

They will also be used to provide traffic reports around the closed section of freeway.