Here are the basic options to crossing the bay, as suggested by NBC Bay Area’s Mike Inouye:
The easiest alternate for you to cross the bay would be by going under the water using the BART system. All East bay lines converge on the tunnel and emerge on the San Francisco side. All Peninsula stops funnel through the Embarcadero station, zipping under the bay and eventually fan out through the East Bay.
The upside: BART is running 24 hours a day through the closure to help out.
The downside: You leave your car where you jump on and that is probably not there where you jump off. Make sure to plan your transportation at the other side of your rail ride. 2.Ferry
The upside: Beautiful and peaceful change. Fridays are quite the social event for many of the routes.
The downside: Timing, access flexibility and potentially seasickness. ;-)
If you're north of the Bay Bridge, the Richmond-San Rafael Bridge (I-580) is your route across the water. If you're south of it, you can take the San Mateo Bridge (Hwy 92) the Dumbarton Bridge (Hwy 84) or Hwy 237 to connect your drive btwn I-880 and Hwy 101.
The upside: At least you have you transportation regardless of timing or destination.
The downside: More mileage, more time and more crowds
Once you are in the City you have the option of a zipcar. That takes a little planning. You need to sign up ahead of time.
My guess is that most will either use the last option or will stay clear of that drive for the duration.