The contents of this publication are not copyrighted. They may be reprinted freely.

and in section 1D.06 on page 114 that:

Traffic control device design or application provisions contained in this Manual shall 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, 511 Travel Information pictograph, National Scenic Byway graphic, and any items under the stewardship of or owned by FHWA. The Caltrans logos consisting of the “CT” symbol and the “Caltrans” logotype are registered service marks and when used on any traffic control device they shall be presented in a uniform and consistent manner as outlined in Caltrans’ Deputy Directive DD-33-R1.