Glossary
Each term has one meaning on this site. The first text is a plain explanation. The quotation is the text of the agency, with a link to its page.
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- Fatal crash
A crash that FARS records. A motor vehicle on a public road is in the crash, and a person dies in 30 days or less after it. A crash on private property is not in FARS.
The words of the agency:
To qualify as a FARS case, the crash had to involve a motor vehicle traveling on a trafficway customarily open to the public and must have resulted in the death of a motorist or a non-motorist within 30 days of the crash.
NHTSA, FARS Analytical User's Manual, 1975-2024, Introduction- Death (fatality)
A person who died in a fatal crash. FARS counts each person with the injury severity "fatal". One fatal crash can have more than one death. A person who dies 31 days or more after a crash is not in FARS.
The words of the agency:
This data element records the number of fatally injured people in the crash.
The data element is derived by counting all people with “Injury Severity” of 4 in the crash.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element C101 Fatalities (FATALS)- Annual file
The first FARS file of a crash year. NHTSA calls it the Annual Report File (ARF). Its counts can change in the final file.
The words of the agency:
The set of first files, known as the Annual Report File (ARF), is released following the crash year.
NHTSA, FARS Analytical User's Manual, 1975-2024, Appendix G, "Analysis of the FARS Annual Report File (ARF)"- Final file
The file that replaces the annual file about one year later. It has the cases and the updates that came after the annual file. The page of release dates shows which file each year has.
The words of the agency:
The ARF is replaced about a year later with a final file, which contains additional cases or updates to cases that had become available after the ARF was released.
NHTSA, FARS Analytical User's Manual, 1975-2024, Appendix G, "Analysis of the FARS Annual Report File (ARF)"- Trafficway
A road, street or highway that is open to the public. FARS records a crash on a trafficway only.
The words of the agency:
Any Road, Street, Or Highway Open To The Public As A Matter Of Right Or Custom For Moving Persons Or Property From One Place To Another.
NHTSA, FARS Encyclopedia, Terms, entry "Trafficway" (NHTSA sets each word of this page with a capital letter.)- Motor vehicle in transport
A motor vehicle that moves on a trafficway, or any other motor vehicle on the roadway. A vehicle that stalled on the roadway is in transport. A crash needs a motor vehicle in transport to be in FARS.
The words of the agency:
A Motor Vehicle In Motion On The Trafficway Or Any Other Motor Vehicle On The Roadway, Including Stalled, Disabled, Or Abandoned Vehicles.
NHTSA, FARS Encyclopedia, Terms, entry "Motor Vehicle In Transport" (NHTSA sets each word of this page with a capital letter.)- Route signing
The kind of route that the sign on the trafficway shows, for example Interstate, US highway or state highway. This site makes a page for a route of these three kinds.
The words of the agency:
This data element identifies the route signing designation of the trafficway on which the crash occurred.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element C11 Route Signing (ROUTE)- Rural and urban
FARS classes the place of a crash as rural or urban. This site gives the share of fatal crashes on a rural road among the crashes that FARS classes as rural or urban.
The words of the agency:
This data element identifies the classification of the segment of the trafficway on which the crash occurred based on FHWA-approved adjusted Census boundaries of small urban and urbanized areas.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element C12A Rural Urban Classification (RUR_URB)- Road function class
The class of a road by the service it gives, from Interstate to local road. The Federal Highway Administration defines the classes. FARS records the class of the road of each crash.
The words of the agency:
This data element identifies the functional classification of the segment of the trafficway on which the crash occurred.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element C12B Functional System (FUNC_SYS)- Light condition
The level of light at the time of the crash: daylight, dawn, dusk, or dark with or without street lights. The count "in the dark" adds the three dark conditions. The share is among the crashes with a reported light condition.
The words of the agency:
This data element records the type/level of light that existed at the time of the crash as indicated in the case material.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element C25 Light Condition (LGT_COND)- Weather
The atmospheric conditions at the time of the crash, such as clear, rain or snow. FARS gives one value for each crash.
The words of the agency:
This derived data element records the prevailing atmospheric conditions that existed at the time of the crash as indicated in the case material.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element C26 Atmospheric Conditions (WEATHER)- Driver recorded as drinking
A fatal crash is in this count when FARS records one or more drivers as drinking. FARS does so when police reported alcohol involvement, or when a test of the driver was positive for alcohol. The count is not a count of drivers over a limit of alcohol. It is the count of the FARS field DR_DRINK.
The words of the agency:
This data element records whether the driver was drinking.
A driver is classified as drinking (alcohol-involved) if the driver has (1) police-reported alcohol involvement, or (2) a positive alcohol test result.
Note that alcohol data is often missing. For that reason, this data element may under-count the actual number of drinking drivers.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element V151 Driver Drinking (DR_DRINK)- Alcohol-impaired driving (NHTSA measure)
NHTSA's own measure. It uses a blood alcohol concentration of .08 g/dL or higher, and NHTSA estimates a value when no test result is known. This site does not give this measure. Its count is not the count of drivers recorded as drinking.
The words of the agency:
Drivers are alcohol-impaired when their blood alcohol concentrations (BACs) are .08 grams per deciliter (g/dL) or higher.
Estimates of alcohol-impaired driving are generated using BAC values reported to the Fatality Analysis Reporting System (FARS) and BAC values imputed when they are not reported.
NHTSA, Alcohol-Impaired Driving: 2023 Data (DOT HS 813 713)A fatal crash is in this count when FARS codes one or more drivers as speeding-related. The codes are racing, exceeded the speed limit, too fast for conditions, and speeding with no detail. It is the field SPEEDREL.
The words of the agency:
This data element identifies if the driver was speeding, and it was related to the crash as identified by law enforcement.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element D22 Speeding Related (SPEEDREL)- No restraint used
The share of vehicle occupants killed with no restraint in use, among the occupants killed whose restraint use FARS records. Motorcycle riders are not in the count. It is the field REST_USE.
The words of the agency:
This data element records the restraint equipment in use by this occupant at the time of the crash.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element P10A Restraint System Use (REST_USE)- Pedestrians and bicyclists
The count is the persons killed of each type. The FARS field PER_TYP gives the type. The count of bicyclists includes other pedalcyclists.
The words of the agency:
This data element describes the role of this person or non-motorist at the time they became involved in the crash.
NHTSA, FARS Analytical User's Manual, 1975-2024, data element P7/NM7 Person Type (PER_TYP)- Motorcyclists
The count is the drivers and passengers killed in a vehicle with a FARS body type of 80 to 89. These types are motorcycles, mopeds, scooters and other motored cycles.
The words of the agency:
A Two- Or Three-wheeled Motor Vehicle Designed To Transport One Or Two People, Including Motorscooters, Minibikes, And Mopeds.
NHTSA, FARS Encyclopedia, Terms, entry "Motorcycle" (NHTSA sets each word of this page with a capital letter.)- Deaths for each 100,000 residents
The deaths of a place in a period, divided by the residents of the place in the same period, times 100,000. Persons who do not live in the place are in the deaths and not in the residents. This site gives no rate for a count of 1 or 2 and none before 2000.
No agency has an entry for this term. The explanation is the own text of the site.
- Deaths for each 100 million vehicle-miles
The deaths of a state in a year, divided by the vehicle-miles that vehicles travel in the state in that year, times 100 million. Only states and the United States have this rate, from 2015.
The words of the agency:
Travel for the rural minor collector and rural/urban local functional systems is estimated by the States based on a model or other means and provided to the FHWA on a summary basis. Travel for all other systems are estimated from State-provided data in the Highway Performance Monitoring System.
Federal Highway Administration, Highway Statistics 2024, table VM-2, note 1- Population vintage
A vintage is one release of the population estimates of the Census Bureau. A new vintage replaces the estimates of all earlier years. This site uses vintage 2025 from 2020, the vintage 2020 file for 2010 to 2019, and the intercensal file for 2000 to 2009.
The words of the agency:
With each new release of annual estimates, the entire time series of estimates is revised for all years back to the last census.
Census Bureau, Population Estimates Program, MethodologyThe words of the agency:
As each vintage of estimates includes all years since the most recent decennial census, the latest vintage of data available supersedes all previously-produced estimates for those dates.
Census Bureau, Population Estimates Program, About- 1 or 2
The text for a count of 1 or 2. A table, a figure and a sentence of this site write it so, for a county, a route and a county in a year. The rule keeps a count that small from naming one event. A rate is not given for it.
No agency has an entry for this term. The explanation is the own text of the site.
- The ten years
The ten newest complete FARS years. The page shows its years. Ten-year rates, factor counts and the tables by weekday, time and road class use this window.
No agency has an entry for this term. The explanation is the own text of the site.
- Rate class
One of five ranges of the ten-year rate for each 100,000 residents. The ranges are the same for each state. A class shows the size of a rate. It is not a judgement of a county.
No agency has an entry for this term. The explanation is the own text of the site.
- Edition
The FARS file that the pages rest on: the year, the kind of file (annual or final) and the date on which NHTSA released it. The edition line at the top of each page shows it.
No agency has an entry for this term. The explanation is the own text of the site.
The site copied the texts of the agencies on . A quotation keeps the spelling of its source.