Racial Bias in Traffic Stops

Grade 7, 140min

In this series of activities on evaluating racial bias in traffic stops and searches, students calculate the probabilities of drivers of different races being searched at traffic stops, and compare their findings to census data to determine if the numbers represent random sampling or show evidence of racial bias.

Students begin by random sampling the color of objects in a bag, combining their data with their peers’ data to increase sample size and thus decrease sampling variability. These colors map to race data of the US driving population, which students compare to real-world numbers. Students learn about their rights during traffic stops and why race matters during interactions with police. Next, they create compound probability tree diagrams with data from the Bureau of Justice Statistics to determine probabilities of being stopped by race, which they contrast with general population data.

Students interpret the data (e.g., 10% of all drivers are Black / African American, but 23% of all searched drivers are Black / African American) and form an evidence-backed conclusion about racial bias in national traffic stops. Finally, students use random sampling again to compare data for their county against their national results, bringing the issue closer to home. This project was inspired by this activity from Rico Gutstein.

Frame from StoryCorps video, Traffic Stop

Topics addressed

Students will be able to



Suggested lesson breakdown

This activity is more of a practice/review project than a teaching tool, and therefore works best towards the end of the unit. Students can work individually, in pairs or in small groups. The timing suggestions below are estimated and are very flexible based on your students’ pace.

Common Core standards