15 U.S.C. § 318
Verified against govinfo.gov as of June 20, 2026View official text on govinfo.gov ↗
The Secretary of Commerce, in cooperation with the United States Postal Service, may arrange a plan by which there shall be displayed on all cars and other conveyances used for transporting United States mail suitable flags or other signals to indicate weather forecasts, cold-wave warnings, frost warnings, and so forth, to be furnished by the Secretary.