What fluorescent color is used on US school zone and pedestrian warning signs?

What fluorescent color is used on US school zone and pedestrian warning signs? Yellow-green. In US traffic-sign standards, fluorescent yellow-green is used with black legends and borders for school warning signs and for many pedestrian-related warning signs.

The color is brighter and more conspicuous than ordinary yellow, especially in low light, poor weather, or visually crowded streets. It is intended to attract attention where children or pedestrians may be especially vulnerable. School-zone signs, school-crossing signs, and some pedestrian or bicycle warning signs can therefore appear in a vivid yellow-green rather than the traditional yellow used for general roadway warnings.

This color is easy to confuse with fluorescent orange, which is associated mainly with temporary traffic control and work zones. Blue is commonly used for services, while pink is reserved for incident-management signs. The MUTCD also allows some variation by sign type and application, so not every pedestrian sign in the country will look fluorescent yellow-green; the stored answer names the standardized fluorescent color itself.