Which data source best normalizes crash incidence to population in a community?

• A. Census tract data
• B. Traffic density data
• C. Weather data
• D. Vehicle age data

Answer: (A)

Normalizing crash incidence to population means comparing crash counts relative to how many people live in an area, so you can fairly compare communities of different sizes. To do that, you need population data tied to a geographic unit. Census tract data provides population counts and defined geographic boundaries for many small areas, enabling you to compute a rate like crashes per 100,000 people for each tract. This lets you compare communities on a common scale and identify areas with unusually high crash rates after accounting for how many people live there. The other options don’t give population figures: traffic density describes how much traffic flows but not population; weather data is about climate; vehicle age data relates to the vehicles themselves, not how many people live in an area.