This sign reminds me of the childen's book Make Way for Ducklings, the story of a family of mallard ducks who take up residence in a park in downtown Boston.  Whether it be ducks in Boston or here in Texas, deer on a mountain highway, or children on a neighborhood street, these diamond-shaped yellow signs are used to help keep everyone safe.  Road crews and runners also wear yellow vests helping to keep them safe by making them more visible to motorists on the streets.

Where do you see yellow being used as a safety measure?  Photograph it today.