The Federal Highway Administration estimates total vehicle miles traveled using an algorithm that includes gas sales, vehicle registration, vehicle fuel economy data, and other data from the Highway Performance Monitoring System. The National Highway Traffic Safety Administration (NHTSA) defines a fatal crash as alcohol related if either a driver or a nonmotorist has a measurable or estimated blood alcohol concentration (BAC) of 0.08 g/dL or above. BAC is measured as a percentage by weight of alcohol in the blood (expressed as grams per deciliter). An elevated BAC level (0.08g/dL and higher) indicates that enough alcohol was consumed by the person tested to impair normal functions. Only deaths that occur within 30 days of the motor vehicle crash are included (less than 2 percent of the total number of deaths occur after 30 days). FARS data are obtained solely from a State's existing documents, including police crash reports, death certificates (coded to ICD-10 V30-V39 [.4-.9], V40-V49 [.4-.9], V50-V59 [.4-.9], V60-V69 [.4-.9], V70-V79 [.4-.9], V81.1, V82.1, V83-V86 [.0-.3], V20-V28 [.3-.9]. V29 [.4-.9], V12-V14 [.3-.9], V19 [.4-.6], V02-V04 [.1, .9], V09.2, V80 [.3-.5], V87 [.0-.8], V89.2), vehicle registration files, and hospital medical reports.
A description of the FARS data set has been published by NHTSA.
A description of the primary measurement used to determine the number of Vehicle Miles Traveled annually in the US has been published by the Department of Transportation (DOT).