Methodology

Every figure on this site is computed from the NHTSA Fatality Analysis Reporting System (FARS) national CSV files for 1975–2024 and the Census Bureau's county population estimates. Data through 31 Dec 2024; this build was generated 30 Sep 2026. This page defines each measure.

What FARS counts

FARS is a census of crashes on public roads in which at least one person died within 30 days of the crash. "Fatal crashes" is the number of such crashes; "deaths" (or "people killed") is the FATALS field summed over crashes. Crashes on private property and deaths later than 30 days are not in FARS. See how FARS counts a fatal crash.

Years and windows

• The accident table is processed for every year 1975–2024; the vehicle and person tables for 2015–2024, the years in which the codes used for factor shares are consistent.
• "Ten-year window" is 2015–2024. Rates, factor shares, time-of-day and road-type distributions use this window. "Previous ten years" is 2005–2014.
• Route pages use route identification from 2000, when the trafficway field became consistent.
• The latest year (2024) is NHTSA's annual release for that year and may be revised in the following year's cycle; see when new data arrives.

Rates per 100,000 residents

A ten-year rate is deaths in the window divided by the sum of each year's population estimate (person-years), times 100,000: an annual rate averaged over the window. A single-year rate divides that year's deaths by that year's estimate. Denominators are the Census Bureau's county totals from three vintages: the 2000–2010 intercensal estimates, the 2010–2020 vintage (2010–2019) and the current vintage (2020 onward). No county estimates before 2000 are used, so no rates are shown for earlier years.

Rates are per resident, not per vehicle-mile. A small county on a busy through route accumulates deaths of people who do not live there, and its rate rises accordingly. The deaths column beside every rate gives the scale.

Counties

Crashes are assigned to the county FARS records. County pages exist for every county in the Census Bureau's current list that has a FARS record; the small number of historical county codes that no longer exist are kept in state totals only, and a handful of documented code changes (Miami-Dade, Oglala Lakota, Kusilvak, the merged Virginia independent cities and several Alaska boroughs) are merged into today's code so trends are continuous. FARS still codes Connecticut by its eight historical counties rather than the planning regions the Census Bureau adopted in 2022; those counties use the 2020 population estimate for 2020 onward.

Factor definitions

• Alcohol: share of fatal crashes in which police reported at least one driver as drinking (DRUNK_DR in the accident table through 2021; the vehicle table's DR_DRINK for 2015–2024, which yields the same count). This is not NHTSA's "alcohol-impaired driving" measure, which uses measured or imputed blood alcohol concentration of 0.08 g/dL or above and runs higher.
• Speeding: share of fatal crashes with at least one driver coded as speeding-related (SPEEDREL codes 2–5: racing, exceeding the limit, too fast for conditions, or yes with specifics unknown).
• Pedestrians and motorcyclists: share of all people killed who were pedestrians (person type 5) or occupants of a motorcycle, moped, scooter or other motored cycle (body types 80–89).
• Unrestrained: among occupants of non-motorcycle vehicles who were killed and whose restraint use was known, the share coded as "none used". Unknown and not-reported cases are excluded from the denominator.
• In darkness: crashes coded dark (lighted, not lighted or lighting unknown) as a share of crashes with a reported light condition. Rural: crashes on roads coded rural as a share of those coded rural or urban.

Routes

A route is the trafficway recorded for the crash (TWAY_ID) where FARS classes the route as Interstate, US highway or state highway. The identifier is normalised to its signed number ("I-65", "US-31", "SR-99"); concatenated identifiers such as "US-31 SR-3" are assigned to the first. Local streets, county roads and unsigned roads are not given pages. A route page needs at least 20 fatal crashes in 2015–2024; the same number in another state is a different page. Mile-marker bins use the FARS milepoint in five-mile ranges and are shown only when at least half the crashes on the route have one.

Time of day and road type

Hour and weekday are the crash's reported time. Road function classes are the FHWA functional system as coded in FARS (FUNC_SYS): interstate; other freeways and expressways; other principal arterial; minor arterial; major collector; minor collector; local. See road function classes.

Small-count suppression and thresholds

• Any county-year or route-year count below three is shown as "1–2", and a per-100,000 figure is not shown for it. County trend charts plot such years at the midpoint of the range.
• Counties with fewer than 20 deaths in the ten-year window are built (so state tables can link to them) but marked noindex, and their trend is shown in five-year totals instead of single years.
• Factor shares are shown only where the entity has at least ten fatal crashes in the window; county lists on factor pages require 100 deaths.

Why figures can differ from NHTSA's tables

• NHTSA's headline national totals are the same sums over the same files; state totals here exclude Puerto Rico and the Virgin Islands, which some NHTSA tables include.
• NHTSA's alcohol-impaired figures use imputed BAC (see above); this site uses the police-reported drinking flag.
• Rates use Census Bureau resident estimates; NHTSA also publishes rates per 100 million vehicle-miles travelled, which are not reproduced here.
• The latest year is revised when NHTSA publishes the following year.