Sources and methods

Fatal crashes

NHTSA's Fatality Analysis Reporting System (FARS), national CSV files for 2020 through 2024, read October 2, 2026: 189,208 crashes and 205,237 deaths. FARS includes every crash on a public road in which someone died within 30 days. We count crashes and deaths by the state, county and city coded in each record, and roads by the trafficway name, merging a numbered route's spellings (I-45, IH 45, I45 frontage) into one.

Large truck: a vehicle body type over 10,000 lbs gross weight, excluding buses and motor homes. Speeding: a driver coded as speeding, racing or too fast for conditions. Drinking: police reported alcohol involvement for a driver; this is the police report, not a blood test. Pedestrian, bicyclist and motorcyclist deaths come from the person records.

Population

US Census Bureau Vintage 2024 estimates for counties and incorporated places. Connecticut crashes are still coded by its eight historic counties, so those pages use the 2020 Census. Rates are deaths a year per 100,000 residents, averaged over the five years.

Which places get a page

A county gets a page with 10 or more fatal crashes in the five years (2,467 counties); a city with 20 or more and at least 25,000 residents (654 cities). Smaller places are listed on their state page.

State law and crash reports

Each deadline, fault rule, insurance minimum and crash-report fee was read from the state statute or the official agency page on the date shown on that page, with the quote kept. A rule is printed only when the quote states it. Where official pages disagreed, we used the statute and say so on the page.

Map outlines

US Census Bureau cartographic boundary files (2025), projected to Albers equal-area.