A nonresident daily commuter indicia shall be displayed in a location on the vehicle which is clearly visible and adjacent to the rear license plate. The corresponding nonresident daily commuter identification card shall be carried at all times in the assigned vehicle and shall be presented to any California peace officer upon demand.
Source:
Section 6700.4, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH§ionNum=6700.4..