In 2010, the 2010 Tour of California moved from February to May (May 16–23), the same time as the Giro d'Italia. It is considered likely that the number of Americans in the Giro and Italians in the Tour of California will decrease. Tour of California organizers seek to make the race a preparatory event for the Tour de France, believing few riders who seek a serious position in the Tour will ride the Giro. The race remained in May in 2011 and 2012.
The leader and overall winner by time after each stage and at the conclusion of the race wears a Yellow Jersey. Originally the leader's jersey was gold, a reference to the California Gold Rush, but in 2009 the jersey color was changed to yellow.
The Blue Jersey is given to the most courageous rider at the end of each stage. In 2008, the jersey was red. George Hincapie has won this jersey three times, after stages in 2008, 2009 and 2010. Jan Bárta won the award twice during the 2011 edition. No one else has won this jersey more than once.
The main sponsor of the event, Amgen, is the producer of the medical drug Erythropoietin, also called EPO. EPO is often used as a performance enhancing drug by professional cyclists. Former professional cyclists that admitted their doping like Tyler Hamilton claim that for some time, most of the worlds top cyclists consumed EPO.
A plan to perform comprehensive anti-doping tests for the Tour 2011 was terminated by the UCI. The plan was to do blood tests performed by the United States Anti-Doping Agency (USADA), which would have been able to detect EPO, but the UCI and the USADA couldn't agree on the details of the doping tests. For the 2013 edition, the UCI elected to reintroduce testing based on the biological passport, as USADA would also take care of pre-race testing, but with no cooperation between the two agencies.