CA Veh Code Section 21803

(a)

The driver of any vehicle approaching any intersection which is controlled by a yield right-of-way sign shall, upon arriving at the sign, yield the right-of-way to any vehicles which have entered the intersection, or which are approaching on the intersecting highway close enough to constitute an immediate hazard, and shall continue to yield the right-of-way to those vehicles until he or she can proceed with reasonable safety.

(b)

A driver having yielded as prescribed in subdivision (a) may proceed to enter the intersection, and the drivers of all other approaching vehicles shall yield the right-of-way to the vehicle entering or crossing the intersection.