Section 4D.17 Visibility,
Shielding, and Positioning of Signal Faces
[Excerpt from existing text of Section 4D.17]:
The use of a signal backplate for target value enhancement should be considered on signal faces viewed against a bright sky or bright or confusing backgrounds.
The use of backplates enhances the contrast between the traffic signals and their surroundings for both day and night conditions, which is also helpful to elderly drivers.
[Recommended Addition of new Option]:
A yellow retroreflective strip no wider than 75 mm (3 in) may be placed around the perimeter of the face of backplates to project a rectangular appearance at night.