Racial bias in traffic enforcement has become a popular line of inquiry, but examinations into explanations for the disparity have been scant. The current research integrates theoretical insights from the racial threat hypothesis with inferences drawn from the empirical analyses of the factors that stimulate officer suspicion. The most intriguing finding from this beat-level examination of the structural predictors of several traffic stop outcome measures concerns the conditional effect of the racial composition of the beat on search rates. The analyses reveal that the search rate increases in areas where the proportion of Black residents is higher; however, this finding is observed only for White motorists. This finding is interpreted as indicating that structural characteristics of an area can provide cues to officers regarding who belongs in that environment. As a result, social control increases among groups whose racial characteristics are inconsistent with the neighborhood racial composition. (Contains 4 tables and 4 notes.)