At least I have options. The bart reaches my town. One unanticipated option is the Casual Carpool. Using CC, a driver can pick up two riders and get into the carpool lane in the bridge. Riders & driver benefit.
I heard about the CC a while ago; I heard about the rules:
Which as it turns out, is pretty close to the 'official rules and etiquette'. I've met some nice folks from my neighborhood and learned some handy shortcuts on the way to the city.
Find a CC pickup location near you and give it a try sometime.