From SFWiki

The Emery Go-Round is a free bus connecting the Emeryville Amtrak station and the MacArthur Bart Station with Emeryville proper.

Each bus is tracked via a GPS and can be seen on the live map. In addition, the schedule is available here. One can additionally track the whereabouts of buses on the route by dialing a phone number listed on all bus signs. The voice prompts will ask you for the stop number posted on the sign. It will respond with the estimated time of arrival of the next bus.