“Traffic Stops in the Pacific Northwest: Competing Hypotheses About Racial
Disparity.” 2008. Journal of Ethnicity in Criminal Justice, 6 (No. 1), 3–22 (with R. G.
Greenleaf and A. Lurigio).
This study examines the distribution of police traffic warning citations in a large
northwestern city. Warning tickets were instituted to document the exercise of police
discretion in the disposition of traffic stops. The paper tests three competing hypotheses
about how these citations are distributed: law enforcement, traffic enforcement, and group
threat. The findings show greater support for the group threat explanation. African
Americans were disproportionately ticketed in the more affluent areas of the city with a
higher per capita income and a higher percentage of home ownership. The data also
demonstrated that traffic officers were more active than patrol officers in predominately
white beats, while patrol officers concentrated more on African American and Asian areas of