Pedestrian Crossing sign (Standard 1-D), a standard warning device specified by General Order 75-D of the California Public Utilities Commission.
<a href="https://en.wikipedia.org/wiki/California_Public_Utilities_Commission" class="extiw" title="w:California Public Utilities Commission">California Public Utilities Commission</a>
<a rel="nofollow" class="external text" href="https://docs.cpuc.ca.gov/PUBLISHED/GENERAL_ORDER/60157.htm">General Order 75-D</a>