Speed laws, as well as other traffic laws, are enacted by the State Legislature and compiled in the California Vehicle Code (CVC).
All states base their speed regulations on the Basic Speed Law: “No person shall drive a vehicle at a speed greater than is reasonable or prudent and in no event at a speed which endangers the safety of persons or property” (CVC 22350).
California state law also establishes maximum speed limits. For example the maximum speed on an undivided two-lane roadway is 55 MPH (CVC 22349b). All other speed limits are called prima facie limits, which are considered by law to be safe and prudent under normal conditions. Certain prima facie limits are established by California law and include the 25 MPH speed limit in business and residential districts and the 25 MPH limit in school zones when children are present.
Additional information may be found on the Speed Limit page.