Once I was asked to stop by Japanese police officer when I was an undergrad student. I had long hair and wearing a cap. I was walking in a dark park with an old bicycle. I might be a bit suspicious. Fair enough. But, I never ever felt great about the way they asked some questions. I understand police officers are doing their jobs, but I wish they can talk a bit more in nice ways.
This story came back to my mind the other day, and I wanted to look into some police-stops data. I doubt if Japanese police would release such data. But, American police, they do. I found a data related to police stops in NY in 2012. You can see when and where police officers asked American citizens to stop. You can also see who they asked to stop. That is, you can see information like age, race, weight, height, and hair color. I can already imagine that police officers had some bias in their suspect selection; they probably asked black / Hispanic people to stop more than white people. But, I have more questions like; which season do police officers ask American citizens to stop. I will dig this data set and see what I can find. Analyses are in progress. To be continued.