By Erik N. Nelson, STAFF WRITER

As frustrating as its traffic and toll booths may make motorists, the Bay Bridge will be missed by many thousands of motorists if they decide to venture into San Francisco this weekend.

At 11:59 p.m. Friday, the lower deck was closed to most eastbound traffic and will remain closed throughout the three-day Labor Day weekend.

One person who will especially miss it will be Sid Abraham, lead dispatcher at 415 Limousine off the city's Market Street.

"I thought it was going to be midnight to 5 a.m. each day," he said, somewhat taken aback after hearing that the lower deck closure would, instead, last straight through until 5 a.m. Tuesday. "Then it's going to be major, oh boy!"

Like many other consumers of cross-bay transportation, Abraham was one of thousands who saw variable message signs along Bay Area freeways, heard radio and television spots or received colorful fliers warning that the area's main artery would be half-closed for demolition to make way for a new, more earthquake-worthy approach viaducts and ramps leading to and from the bridge's western end.

But he missed the details, thinking it would be as limited as previous closures, like the one in June that was limited to late-night hours.

To ease the loss of the eastbound deck, transit service will be increased, with BART running 24 hours through Monday evening, AC Transit running eastbound bus service from the Transbay Terminal at 40 minutes past each hour and both the Oakland-Alameda and the Vallejo Baylink ferry services more than doubling their runs. Other buses will also be escorted across the bridge.

The state's transportation agency, Caltrans, isin the midst of a $429 million project to replace the massive concrete structures that funnel more than 200,000 vehicles a day on and off of the Bay Bridge. The new structure is engineered to withstand an 8 magnitude earthquake.

Caltrans' project managers decided to do this phase of demolition work, which will break up more than 1,000 feet of concrete that now carries Interstate 80 up to the bridge, on Labor Day weekend because the long weekend will permit them to finish the job in one fell swoop and there are no major public events scheduled.

To warn people about the closure, Caltrans has mounted an all-out effort to educate the public, aided by other agencies such as the Metropolitan Transportation Commission.

Commission spokesman John Goodwin said "The extent that we've reached out to people has gone really well, to the extent that we've been in direct contact with three wedding parties" that involved shuttling bridesmaids and groomsmen and guests across the Bay.

The Baltimore Orioles, who are playing the Oakland A's this weekend, will be shuttled from their hotel in San Francisco to the Oakland Coliseum by a bus that will stand in line at the Transbay Terminal for an escort past the demolition zone, Goodwin explained.