670.5.
(a) The Flag of the United States of America and the Flag of the State of California may be displayed on a sidewalk located in or abutting on a state highway situated within a city, if the type of flagholder and the method of its installation and maintenance are not in violation of the department’s rules.(b) (1) A city or county may display the Flag of the United States of America or the Flag of the State of California, or both, as part of a gateway monument if the flags are maintained by the city or county.
(2) As used in this subdivision, a “gateway monument” means any freestanding structure or sign, or nonintegral or nonrequired highway feature, constructed within the state’s right-of-way, that communicates the name of the city or county.