The first 24 hours of the Bay Bridge's holiday weekend closure of its westbound lanes went smooth, a Caltrans spokesman said, with other arterials and mass transit seeing increased traffic.

BART reported thousands of extra riders as the transit system ran extra trains Saturday, and other Bay Area bridges reported some delays as motorists were forced to take detours to reach San Francisco from the East Bay.

Traffic on the Golden Gate Bridge was heavier than normal, bridge spokeswoman Mary Currie said, but vehicles were still moving about 35 mph at stretches of the bridge.

The Bay Bridge's westbound lanes closed at 8 p.m. Friday and are scheduled to reopen at 5 a.m. Tuesday.

Steamrollers replace commuters Saturday afternoon Feb. 18, 2012 as the President’s Day weekend Bay Bridge closure enters its second day. Actual
Steamrollers replace commuters Saturday afternoon Feb. 18, 2012 as the President's Day weekend Bay Bridge closure enters its second day. Actual commuters will see a slightly different approach to the span when the bridge reopens Tuesday morning. (Karl Mondon/Staff)

Motorists still are able to drive on the lower deck from San Francisco toward Oakland.

BART, which began running trains five hours earlier than normal, reported that 87,500 riders traveled on BART from 1 a.m. to 2 p.m. Saturday, spokeswoman Luna Salaver said, up 17,500 from their normal Saturday morning service.

On a normal Saturday, in which hours run from 6 a.m. to midnight, approximately 182,000 riders use BART, Salaver said.

With the bridge closed, "we expect (Saturday's) numbers to far surpass that," she said.

To make up for the bridge closure, BART has been running trains to 14 select stations over the three-day weekend from 1 to 6 a.m.

BART customers can go to BART.gov for more info on train service during the bridge closure.

The 75-year-old Bay Bridge is nearly 4½ miles long and carries about 260,000 vehicles a day between San Francisco and Oakland.

The bridge has not closed for an entire weekend since 2009, when a portion of its eastern span was replaced with a new double-deck section.

Rick Hurd and Chris De Benedetti cover public safety. Follow them on Twitter at Twitter.com/3rdERH and /cdebenedetti.