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.
According to the Alaska DOT&PF:
The Alaska Traffic Manual Supplement (ATMS) does not modify the Manual on Uniform Traffic Control Devices (MUTCD) standard statement regarding traffic control devices in the public domain and restriction from protecting those devices by patent or copyright. Accordingly the MUTCD standard applies in this case andall devices contained in either or both the MUTCD and ATMS are in the public domain and shall not be protected by patent or copyright, except for the Interstate Shield.
24 in by 24 in (600 mm by 600 mm) Alaska highway shield, made to the specifications of the 2003 sign design specifications (sign M1-5). Uses the Roadgeek 2005 fontsarchive copy at the Wayback Machine. (United States law does not permit the copyrighting of typeface designs, and the fonts are meant to be copies of a U.S. Government-produced work anyway.)
Note: the ALASKA might not be perfect, as the specs do not specify the font, so I had to copy it from the PDF.