Caltrans road sign G24-6
<a href="https://en.wikipedia.org/wiki/California_Department_of_Transportation" class="extiw" title="en:California Department of Transportation">California Department of Transportation (Caltrans)</a>
<ul><li>Sign specifications: <a rel="nofollow" class="external free" href="http://www.dot.ca.gov/hq/traffops/engineering/control-devices/specs/G24-6.pdf">http://www.dot.ca.gov/hq/traffops/engineering/control-devices/specs/G24-6.pdf</a> (from 1971)(NOTE:Measurements are converted from inches to millimeters and rounded off).</li>
<li>Arrow: from <a rel="nofollow" class="external text" href="http://www.dot.ca.gov/hq/traffops/engineering/control-devices/specs/specappendix_4.pdf">Caltrans Sign Specifications Appendix 4</a></li></ul>