The FHWA recently posted proposed changes to the MUTCD.  A call for comments has been issued and ADOT is in the process of reviewing the proposed updates.  If you are interested in providing comments please reach out to webmaster@itsaz.org.  Comments are due to Hasina Luna (hluna2@azdot.gov) no later than 26 February 2021

A link to the proposed changes can be found here – https://beta.regulations.gov/document/FHWA-2020-0001-0038.  Thank you for your time in this process!