Yet the Wyatt Earp killed Johnny Ringo claim can be found in four separate sources (Forrestine Hooker, John Flood, Frank Lockwood, and Frederick Bechdolt), and each person had contact with Wyatt Earp or stated he told them the story.
A TCD is any sign, signal or marking that involves traffic. A speed limit sign is a type of TCD. A TCD ticket is a lesser violation carrying only 2 points. Even the lowest level speeding violation carries 3 points and the stigma of a speeding violation.
These are messages in material symbolic form. You might argue that Iris would be a better symbol for FTD, what with the rainbow association and all (nature, colors), but no one knows who she is just by looking. Best they could do would be a rainbow lady, and that wouldn't express the quick/convenient end of the business FTD wants to communicate.