Lassen County Route A3 shield in California. Based upon Image:US_DOT_FHWA_MUTCD_SHS_2004_3-7_M1-6_450x450mm_00.svg . Edited in w:Inkscape .

This file is in the public domain because it comes from the Manual on Uniform Traffic Control Devices , sign number M1-6, which states specifically on page I-1 that : Any traffic control device design or application provision contained in this Manual shall be considered to be in the public domain . Traffic control devices contained in this Manual shall not be protected by a patent, trademark, or copyright , except for the Interstate Shield and any other items owned by FHWA.