Detroit's first stop sign is oftentimes described as a 2' by 2' white square with black lettering. Unfortunately, I couldn't track down an image of it, but the photo here was taken in 1915 at the ...

The idea of red meaning "stop" dates back to British railroad regulations of the 1840s—but for a while, a dearth of fade-proof red materials meant that many American stop signs were yellow instead.

They’re hard to miss, those big red-and-white signs in the shape of a octagon that declare “STOP.” But some Boise-area motorists — including at a main intersection at Bown Crossing — are ...