For those wanting to understand the police and policing in the United States, political science hasn't been much of a help. Sure, a few political scientists (i.e., James Q. Wilson, William Ker Muir, Michael K. Brown, and Michael Lipsky) produced classic bureaucracy books by studying the police and policing. Compared to other disciplines (e.g., sociology), however, political science is relatively mute and ill-informed about the police and policing. That's changing.
Political scientists are beginning anew to study the police in the United States, especially encounters between the police and denizens. Greater media attention to and variation in public attitudes about police–denizen encounters drive much of the contemporary attention political science pays to the police and policing. That's especially true of encounters involving the use of force, especially lethal force, by police. Moreover, some encounters spark contentious political action and electoral mobilization by denizens, sometimes leading to policy change. While spectacular encounters between the police and denizens deserve study, unremarkable police–denizen encounters merit attention, too. These include a quotidian practice of policing—traffic stops.
Police stops of vehicles are a common way denizens, as drivers and passengers, come in contact with and experience the state. They are moments where the police as “street-level bureaucrats” exercise wide discretion to stop, detain, release, or arrest citizens and non-citizens. Additionally, police stops of vehicles are moments that may affirm for or teach their occupants how much regard the police have for them, as individuals and group members. Plus, some police stops of vehicles produce spectacular police violence against drivers and passengers (e.g., the non-lethal beating of Rodney King and the fatal shooting of Philando Castile).
The nascent political science studies of police traffic stops take two lanes, moving in parallel. The first lane of study examines the perceptions and attitudes of drivers about their experiences with police stops, and highlights disparities in whom police stop and how they treat them. Pulled Over: How Police Stops Define Race and Citizenship, authored by Charles Epp, Steven Maynard-Moody, and Donald Haider-Markel, exemplifies this type of study. (I don't review it here. But, I've read, taught, and learned from it.) A key limit of this study type is the inability to match survey respondents to police records of stops. Consequently, they can't empirically demonstrate, confirm, or causally explain racial and other disparities (e.g., gender and age) in police stops.
The second lane of study examines official encounter data. It leverages police records of driver stops to describe official rates of disparities and to conduct hypothesis testing. Such studies are possible because governments increasingly publish rich data on traffic stops. The best example is NC. In 1999, it enacted a law to collect and publish data on all stops by municipal police departments, county sheriffs’ offices, and the state highway patrol. The purpose was to determine the degree of racial profiling by police of drivers in (and passing through) the state. Frank Baumgartner, Derek Epp, and Kelsey Shoub leverage that data, which covers 2002 through 2016. Their book Suspect Citizens: What 20 Million Traffic Stops Tell Us About Policing and Race is the forerunner for demonstrating with government data racial disparities in traffic stops, as well as correlates that could reduce them.
Suspect Citizens is concise. Yet, its 10 short chapters cover much procedural, theoretical, and empirical ground about police stops of drivers in NC. Although the Tar Heel State is its sole focus and the study isn't causal, due to its data, Suspect Citizens has resonance beyond that state and its region. At a minimum, Suspect Citizens is a solid tutorial on the legal justifications for police traffic stops and the realities of racial disparities in stops. Furthermore, it combines its immense dataset with methodological rigor, legislative history, and data visualizations to produce fascinating analyses of statewide and agency-level variation in traffic stops. Additionally, it has at least two unassailable takeaways about racial disparities in the use of the most problematic set of traffic stops, namely investigatory stops. First, most stops don't yield contraband. That undermines a key rationale for the overwhelming majority of investigatory stops and the use of traffic stops to prosecute the “War on Drugs.” Second, when stops produce contraband, White drivers and passengers are more likely than non-White drivers and passengers to possess it. That undermines the purported merit of racial profiling of drivers, further revealing the faultiness of racialized policing.
Although the entire book should interest scholars of racial and ethnic politics, as well as bureaucracy, policy adoption, and institutional reform, two chapters, in particular, are worth mentioning. There's the chapter demonstrating that the increased political incorporation of African-Americans, measured by Black descriptive representation in local and county government and Black voter participation at both scales, is associated with statistically significant and substantively meaningful reductions in the racial disparities in traffic stops. As it concludes, “Power matters. It changes the behavior of the police” (p. 186). And there's the chapter explicitly examining stops of Latinx drivers. It observes big enough disparities to raise serious questions about officer discretion in stopping, procedural justice during stops, and punitive treatment of Latinx drivers compared to White drivers, permitting readers to wonder why “whites really are a privileged class when it comes to driving on the roadways” (p. 152).
Beyond the knowledge the authors share about racial disparities in traffics stops, they also share their underlying data files via an online repository. All files are clean and structured for download, replication, and extension. Teachers of quantitative methods courses looking for data for class assignments will appreciate this, as will scholars, be they emerging or established, looking for high-quality data for new projects on the politics of policing, at least if their focus is on traffic stops, either as a dependent variable or as independent variables.
In sum, I highly recommend Suspect Citizens.
