I worked in this area for the state of MD at one of the foremost traffic records outfits in the US and have done this work previously, there are a few considera

I worked in this area for the state of MD at one of the foremost traffic records outfits in the US and have done this work previously, there are a few considerations you are leaving out which comes as a result of knowing these data. You want to never look at things at the citation level, you should group it into stops. One driver can get many citations per stop, which confounds your findings..grouping can be done by making an ID of DL#+Date of stop. If time is included, put that on ONLY if it has the same time for all citation issued in the stop (like it is here in MD) - You could end here, or you could add an indication Y/N for whether a citation was issued. This way, you are looking at stops where at least 1 citation was issued, instead of 3 counts for a race off of one stop where three tickets were issued. Also, the racial categories are based upon the DMV database, and what options they have permitted. The confounder here is racially ambiguous persons may be misclassified, while obviously black people etc will reliably be called such. Additionally, you want to use something like the National Household Travel Survey to get an idea of the racial background of DRIVERS in the area you are examining. It is quite possible that an area has more drivers of a certain race. Note this still will not be perfect due to out of jurisdiction drivers. Please contact me with any questions. Very interesting stuff, I just want to make sure you do it right.....if you hope to make any changes at the govt level, these considerations will be widely known in the traffic records sector.