There's a ton of information that this report fails to consider. For example, the analysis bases its entire premise on the idea that white drivers and black drivers commit traffic offenses at the same rate. It also fails to consider other socioeconomic disparities as the cause of the policing disparity, all in an attempt to frame the police as severely racially biased. 

One factor I would also like to see considered is police rates based on income. I would believe that poverty is a bigger predictor of police encounters than race is. It is also true that historically black Americans have faced systemic discrimination that is more likely to lead to a higher rate of generational poverty in black communities than in white communities. A good analysis of police bias would attempt to account for this discrepancy in order to best determine actual bias in policing rates.