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.
{{Information| |Description=Iowa Highway marker. Uses the standard circle route marker with the FHWA font (type D for 1 digit routes, type C for 2d, type 3 for 3d |Source=[http://www.erl.dot.state.ia.us/APR_2006/RS/content_eng/rd41.pdf http://www.erl.dot