What does a purple ribbon mean?

Hmmm, from that shopping list on Wiki one of the most probable meanings for this particular ribbon is:

It is also a symbol used by 4 R Kids Sake whose mission is to protect our children from preventable injuries and death in and around cars. They were the driving force behind purple ribbon month in CA.

The race car in question is in CA and it is sponsored by a wrecking yard. Wrecking yards probably see far more than their fair share of the residue left after kids are killed in auto accidents.