I came across a database of traffic violations from Montgomery County, Maryland, which is the most populous county in the state, located adjacent to Washington D.C. The data include all “electronic traffic violations” since January 1, 2012, so this analysis is based on 34 months of records.

The first item is a pair of maps showing point distribution and density. This highlights major traffic routes, and it’s fun to see the D.C. border (bottom right) defined by a red mass.

The second item is a graph comparing how traffic violations are distributed among races. Hispanic is not a race, but the dataset uses it as such, so I’ve included it here as a bin. The blue bar shows the percentage of violations committed by each group, separated by men (light blue) and women (dark blue). The orange bar shows the percentage of the county population represented by each demographic. So if the blue bar is taller than the orange bar, that group commits (or is accused of) a higher number of traffic violations per capita.

The third item displays the simple ratio of citations per warning for each demographic. When a violation occurs, the person is either issued a citation, a warning, or a safety equipment repair order. This graph ignores the latter category. Values great than one indicate the demographic is more likely to get a citation than a warning.

The fourth item shows the age of cars by race for all violations.

The fifth item provides a time series of when each race commits violations throughout the day.

The final item considers all speeding violations. It shows, for each speed limit, how many miles per hour over the limit the person was driving. There were also data for 20 mph and 65 mph limits, but they were too small for a robust calculation.

Data source: https://catalog.data.gov/dataset/traffic-violations