Border Patrol agent conducts a technique called "Dragging" in which imprints are cleared at the start of the shift in order to better determine a time line of when crossings happen. Border Patrol in San Diego, CA, USA (<a href="//commons.wikimedia.org/wiki/U.S._Customs_and_Border_Protection" title="U.S. Customs and Border Protection">U.S. Customs and Border Protection</a> - <a href="//commons.wikimedia.org/wiki/United_States_Department_of_Homeland_Security" title="United States Department of Homeland Security">United States Department of Homeland Security</a>) - Text by U.S. Customs and Border Protection
Gerald L. Nino, U.S. Customs and Border Protection
<a rel="nofollow" class="external free" href="http://www.cbp.gov/xp/cgov/newsroom/photo_gallery/afc/bp/44.xml">http://www.cbp.gov/xp/cgov/newsroom/photo_gallery/afc/bp/44.xml</a> (file <code>Cbp44.jpg</code>)