The Three Feet for Safety act became law in California on September 14, 2014.  It requires drivers to stay at least three feet away from a bicyclist who is moving in the same direction when the driver is overtaking and passing the bicyclist.  The text of the act is now part of the Vehicle Code and can be seen at https://www.dmv.ca.gov/pubs/vctop/d11/vc21760.htm

The law imposes a $35 fine for drivers who pass too close if the bicyclist is not injured, and $220 if the bicyclist is injured, unless the driver can prove it was impossible to provide the three feet of clearance.  However, most traffic lanes are 11' or 12' wide and most cars are 6' or 7' wide, so all drivers really have to do is stay to the left when passing a bicyclist and there should be adequate clearance.  

Stay safe out there!