WEST LOS ANGELES (CNS) - Two of the four northbound lanes on the San  Diego Freeway, which were closed overnight as work continued on Sepulveda Pass  road improvements, reopened ahead of schedule.

However, access will remain reduced to two lanes today between  Mulholland Drive and Ventura. And, transition roads onto the northbound 405  from the Santa Monica (10) Freeway will remain closed until early Tuesday  morning.

As has been the case throughout what was billed as ``Jamzilla,''  traffic delays have remained manageable, and much of the feared congestion has  not materialized because many motorists avoided the area during the Presidents  Day weekend.

On Sunday, construction plans changed midafternoon, and workers began  removing barriers to some on ramps to the northbound San Diego (405) Freeway.  Ramps at Santa Monica and Wilshire boulevards were reopened and remained open  all night, even during the midnight to 4:30 a.m. road closures.

And although most schools and government agencies are closed today for  the  Presidents Day holiday, Metro officials are still recommending that 405  leave extra time to reach their destinations.

'`People should be prepared for extra traffic on the 405 -- more  congestion than so far," Metro spokesman Paul Gonzales warned.

Overnight, crews dug up the center median near Ventura Boulevard. It is  being shifted 20 feet west, and the entire northbound pavement will be dug up  and replaced during the next two overnight closures.

Saturday saw a huge traffic jam on the Santa Monica (10) Freeway, where  electronic signs advised that two lanes on the northbound 405 were open in  Sepulveda Pass. While that was true, the signs failed to note that transition  roads from the 10 to the 405 north were closed because of Jamzilla, and there  was no direct connection from the 10 to the pass.

That apparently contributed to observed swerving and confusion on the 10  at the 405 all day Saturday. At one point, traffic on the westbound 10 was  backed up from La Cienega Boulevard to the ramp blockades at the 405.

Today, the electronic signs on the 10 said ramps to the 405 north were  closed. There was no congestion observed at the 10/405 interchange, although  Sunday morning traffic was negligible in all directions.

Metro has announced that the 10's connectors to the northbound 405 would  remain closed until the end of Jamzilla at 6 a.m. Tuesday. The California  Highway Patrol recommended extending the connector road closures, citing driver  safety and the impact to traffic on the 405, according to Metro.

At midnight tonight, all lanes of the northbound 405 will close one last  time before all lanes reopen no later than 6 a.m. Tuesday.

Advice, updates and details on the freeway closures are available at  http://www.lawa.org/405 and motorists can also access a Jamzilla hotline by  calling 5-1-1 and saying ``Jamzilla'' or by visiting http://www.go511.com.