Have you seen the size of the UCSF shuttle buses? They are tiny compared to the tourist coach sized google buses. Also they don't just take UCSF staff and students, they also take patients.

Googlers can take the Caltrain to Mountainview and hop on the free shuttle buses which drop them off at their campus. Why don't they do that?

Or since Google has an office in San Francisco here's a better idea - let people who live in San Francisco work from that office, and people who live outside work at Mountainview.