Add the following Standard to the end of Paragraph 01, Subsection A, in MUTCD Section 1A.13:

Site-specific conditions may lead agencies to determine that it is impossible or impractical to comply with a Standard and that they must deviate from the requirement of a particular Standard at that location or others having the same condition. In such limited specific cases, the deviation is allowed provided that the agency or official having jurisdiction fully documents the engineering reasons for the deviation.

The FHWA can also be requested to review the site-specific condition and the proposed deviation and, if appropriate, issue an Official Interpretation to clarify the application of the Standard to that condition.