TdF and colour of dossards

[daeno]

Watching the TdF and just realized that some teams/riders have different coloured dossards

CSC - black on fluo yellow
Schumacher / Gerolsteiner - white on red

Most seam to be the standard black on white.

Does the colour mean something or is it simply for contrast against their kit ? Although, FdJ have white dossards on their white kit...

[Greenbank]

yellow background dossards are the current leading team.

White on red = combative (for Schumacher at least).

Dunno why the rest of Gerolsteiner would have them (although they do have the current polka dot jersey rider in Kohl)