There was a report today that said in Kingston Ontario, cops are 3.5 times more likley to pull a black person over than a white person. On CBC they showed this test by Harvard university that claims to show whether you have a preference for one race or the other.
https://implicit.harvard.edu/implicit/
http://news.bbc.co.uk/1/hi/magazine/4447471.stm
They also have a ton of other tests.
I came out as slightly preferential to white people. They say that most people are preferential to white people, even people of other races I suppose because of the way we are brought up.