16 An alternative background color other than the normal guide
sign color of green may be used for Street Name (D3-1 or D3-1a)
signs where the highway agency determines this is necessary to assist road users in determining jurisdictional authority for roads.
Standard:
17 Alternative background colors shall not be used for Advance Street Name (D3-2)
signs(see Section 2D.44).
18 The only acceptable alternative background colors for Street Name (D3-1 or D3-1a)
signs shall be blue, brown, or white. Regardless of whether green, blue, or brown is used as the background color for Street Name (D3-1 or D3-1a)
signs, the legend (and border, if used) shall be white. For Street Name
signs that use a white background, the legend (and border, if used) shall be black.
Guidance:
19 An alternative background color for Street Name
signs, if used, should be...(more:
MUTCD 2009 page 163
