We provide the first causal analysis of how state and federal minimum wage policies in the U.S. have affected labor market frictions and racial wage gaps. Using stacked event studies, binned difference-in-differences estimators, within-person analyses and classic panel methods, we find that minimum wages increased wages of black workers between 16 and 64% more than among white workers and reduced the overall black-white wage gap by 10% (and by 56% among workers most affected by the policies).
Racial differences in initial wages cannot explain this differential effect. Rather, minimum wages expand job opportunities for black workers more than for white workers. We present a model with labor market frictions in which minimum wages expand the job search radius of workers who do not own automobiles and who live farther from jobs. Our causal results using the ACS show that minimum wages increase commuting via automobile among black workers but not among white workers, supporting our model. Minimum wages also reduce racial gaps in separations and hires, further suggesting the policies especially enhance job opportunities for black workers.