"Is it the "dirty hippie" effect?" sort of, read between the lines of the story, driver's second language is English, etc, there are two driving experiences in America, driving while white and driving while minority. The author seemed shocked to experience a fairly normal "driving while minority". I didn't find the story all that unusual from discussion with minority coworkers. If the driver was white, they would not have been hassled as per departmental policy, so there wouldn't have been a story.

Looking at the history of enforcement of Jim Crow laws, being treated as a "dirty hippie" can be considered progress in race relations. Nobody got beaten, jailed, shot, or lynched.