There will have to be a controlled experiment.
Find two boys, one white and one black. Dress them both alike. Give them both a "toy" gun. Place them both on a playground (asphalt or otherwise). Call the cops and report these boys and their "guns". See which one the cops shoot.
This may come as a surprise to you and other race baiters, but....
http://www.spokesman.com/stories/2014/sep/05/wsu-study-finds-local-officers-slower-to-fire-at/
According to the results of the research, law enforcement took 1.34 seconds longer to shoot a black suspect than a white suspect when all other factors were the same.
In addition, the study found that law enforcement officers were 25 times less likely to shoot unarmed black suspects as they were unarmed white suspects.
All of the law enforcement participants in the study were white.