Add the following Guidance to the end of paragraph 04 in MUTCD Section 1A.09:

The decision to use a particular device at a particular location should be made on the basis of either an engineering study or the application of engineering judgment. Thus, while this manual provides Standards, Guidance, and Options for the design and application of traffic control devices, this manual should not be considered a substitute for engineering judgment.

Engineering judgment should be exercised in the selection and application of traffic control devices, as well as in the location and design of the roads and streets that the devices complement.

PDFWAC 468-95-017

Engineering study and engineering judgment.