Mambo95 said:
Yeah, you can trademark colours. You have to have a very strong link between the company/product and it's only for very specific uses. There aren't many colour trademarks (maybe about 100), but the Tour would almost certainly be able to get one if they wanted (they haven't though).
Here's a list of them:
http://www.copat.de/markenformen/Farbmarken2007.pdf
But as you say, it has to be very specific uses etc, for instance i beleive flymo have the orange coloour protected in this country, when used specifically on lawnmowers or garden tools, as obviously a company producing lawnmowers in the same colour as flymo is doing so to try and benefit from that colour association.
but there is precedent for that, flymo have built up a reputation as a brand, flymo have always used a certain colour, there is something there to protect.
The ASO would have a very hard job protecting predominantly yellow as a cycle shirt colour. Polka dot yes, that is immediately identifyable as the king of the mountains, and anyone producing a cycle shirt in that design is clearly trying to benefit from the tours design, but yellow, nah. Dont think it would hold.