It’s not just a training problem. Indiscriminate traffic stops are dangerous and unnecessary—no matter who conducts them.

A decade ago, the killings of Sandra Bland and Philando Castile forced people in the United States to reckon with the harms of traffic stops—especially for people of color. In the years since, many jurisdictions have become safer by curbing the use of traffic stops as a law enforcement tool. But in much of the country, the harms have persisted. Now ...