The goal of this study is not to establish that there is systemic racism in policing in general or in traffic stops in particular. That's been well documented,

The goal of this study is not to establish that there is systemic racism in policing in general or in traffic stops in particular. That's been well documented, for decades, and it's surprising to see people denying it or expecting this study to reconfirm something so well established. This study is trying to connect the dots from early warning signs in a traffic stop to disproportionately-bad outcomes that are faced by minorities. They used the data they had to try to connect the dots, drew some inferences, but much more is left to be studied here.