Revision 6 the 2014 edition of the <i>California Manual on Uniform Traffic Control Devices</i>, the legal standard for all traffic control devices in the U.S. state of California.
California Department of Transportation
<a rel="nofollow" class="external text" href="https://dot.ca.gov/programs/safety-programs/camutcd/camutcd-files">California Department of Transportation official website</a> <a rel="nofollow" class="external autonumber" href="https://dot.ca.gov/-/media/dot-media/programs/safety-programs/documents/ca-mutcd/rev6/camutcd2014-rev6.pdf">[1]</a>