You should read Policing the Open Road and Suspect Citizens, but if you won’t you should at least read the conclusion from Suspect Citizens available for free at the link provided.

Here’s a choice, long excerpt about traffic stop data in North Carolina:

Today, after eighteen years of data collection have assembled over 20 million observations, we can report that a two-to-one disparity, far from being an aberration, is in fact the statewide average; many police agencies are much more disparate in their treatment of black motorists. And, as we showed in Chapter 7, these disparities are not limited to blacks; Hispanics are also much more likely to be searched and arrested than whites…

Another key element of our findings is that these tactics do not appear to have any readily apparent crime-fighting benefits. When contraband is discovered it is almost always in small amounts, so much so that the typical contraband “hit” does not even lead to an arrest. To boot, those demographic groups that are most likely to experience a search (young minority men) are actually less likely to be found with contraband. Hispanics in particular are much more likely to be subjected to “fruitless search” than whites or blacks. When we look at the behaviors associated with each police officer, we find no correlation between a propensity to search and the propensity to find contraband, suggesting that there are no overarching standards, that training does not produce a clear profile of when to search, and that it may well be an idiosyncratic guessing game, with each officer using his or her own judgment.

Traffic stops can certainly be a traffic safety tool, and we have shown that when officers focus on traffic safety, the racial disparities apparent in the outcomes of those stops are greatly reduced. Disparities are higher when officers use the rules of the road as a pretext to pull over those drivers who attract their attention for reasons unrelated to the safety of their driving.

In other words, traffic enforcement is all about the suspension of the Fourth Amendment, just as Policing the Open Road frames it. Cops are stopping people of color, using those stops as a pretext for searches that would be illegal in any other context, and those searches are failing to turn up much illegal activity. The reality is that traffic enforcement is not about safety, but instead about using state power to intimidate Black and Hispanic people.

The goals of traffic enforcement do not require police, and the actions of police do not support those goals. We need to decriminalize and remove policing from them. Departments of Transportation can handle traffic enforcement, using cameras and, when necessary, patrols of non-armed civil servants. We can end the threat of search or seizure or physical abuse on the roads entirely in favor of simple citations and providing assistance.

We should defund the police, and traffic enforcement is a great place to start.