Pulling back the veil of darkness: A proposed road map to disentangle racial disparities in traffic stops, a research note

Abstract

The veil of darkness (VOD) is a practical and rigorous methodology for examining racial disparities in police traffic stop behavior. Past research, however, has been littered with methodological inconsistencies inhibiting cross-study comparison and decisions regarding policy. Accordingly, we clarify four aspects of its implementation: 1) coding daylight, our treatment condition; 2) constructing an intertwilight period; 3) accounting for seasonal differences in driving or patrol patterns; and 4) modeling VOD multivariable regression equations. We discuss the theoretical and practical implications of methodological decisions as they pertain to the method's functionality as a natural experiment. Furthermore, we propose a novel weighting procedure to account for seasonal driving population differences. We examined more than 50,000 traffic stops conducted by Michigan State Police during 2021 to demonstrate our suggested framework for future analyses.