Session 38 Alcohol Data In The Fatality Analysis Reporting System (FARS)

National Center for Statistics & AnalysisPeople Saving People

128th Annual Traffic Records Forum, Orlando, FL

Session 38Alcohol Data In The

Fatality Analysis Reporting System (FARS)

Trends and Testing Patterns Anders Longthorne

Mathematical Analysis Division



NHTSA Definitions

Blood Alcohol Concentration (BAC) BAC is measured as the weight of alcohol in the blood (grams/deciliter or g/dl). Actively Involved Participant A Driver (including MC operators) or Non-Occupant Involved in the Fatal Crash. Crash BAC Maximum BAC level of any Actively Involved Participant in the Fatal Crash. Alcohol Related Driver / Non-Occupant A Driver or Non-Occupant with a Positive BAC.



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Driver Pedestrian Pedalcyclist

In Year 2000 55 Percent of Drivers Had an “Unknown” BAC Test Result

“Unknown” BAC results as Percent of all BAC resultsBy Actively Involved Person Type

Source: 1982-2000 Final FARS File



State Total Unknown Percent Unknown Total Drivers

Maine 19 8 229Minnesota 192 22 883Vermont 22 24 91Nebraska 95 26 369Mississippi 389 31 1,236Georgia 682 32 2,149South Dakota 69 32 217New Hampshire 56 33 168Delaware 60 34 179Arkansas 312 37 852

INVOLVED DRIVERS BY ALCOHOL TEST RESULTS - FARS 2000

The Ten Best States for TestingDrivers BAC

Source: 2000 Final FARS File



State Total Unknown Percent Unknown Total Drivers

North Carolina 1,950 90 2,162South Carolina 1,221 87 1,411Texas 3,860 76 5,061Arizona 995 74 1,348Dist of Columbia 46 74 62New York 1,482 74 2,005Montana 204 72 284Alabama 885 65 1,363Virginia 841 65 1,284Massachusetts 385 64 605

INVOLVED DRIVERS BY ALCOHOL TEST RESULTS - FARS 2000

The Ten Worst States for TestingDrivers BAC




Multiple Imputation Improves the Quality of FARS Data

Unknown= 55%

Known= 45%

Rate of Driver Alcohol Testing for USA for Year 2000

Multiple Imputation calculatesValues for these “Unknown” Values and allows for valid Statistical Analysis




0

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60

70

1982

1983

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1987

1988

1989

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2000

Perc

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Crashes Fatalities

Fatality Rate closely follows Fatal Crash Rate

Alcohol Related Fatal Crashes and Fatalities as a Percent of all Fatal Crashes and Fatalities




0

1020

3040

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70

1982

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Perc

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0.08 and above g/ dl 0.01-0.07 g/ dl

Most Alcohol Related Crashes Involve BAC levels of 0.08 g/dl

or Greater.

Alcohol Related Fatal Crashes as a Percent of all Fatal Crashes by the Crash BAC




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60

70

1982

1983

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1989

1990

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1995

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2000

Perc

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Single Multiple

Most Alcohol Related Crashes are Single Vehicle Events

Alcohol Related Fatal Crashes as a % of all Fatal Crashes by the Number of Vehicles in the Crash




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Driver Pedestrian Pedalcyclist

Alcohol Trends of Actively Involved persons

Trend of Alcohol Related Drivers, Pedestrians and Pedalcyclists

Source: 1982-2000 FARS File



63%

37%

Fatally Injured Drivers More Likely to be Alcohol Related

Alcohol Related Drivers as Percent of Drivers Involved in Fatal Crashes for Year 2000

84%

16%

All Fatally Injured Drivers All Surviving Drivers

Alcohol Related

No Alcohol Related

Alcohol Related

No Alcohol Related




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1982

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Perc

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% Alcohol Related of All Killed % Alcohol Related of All Surviving

Fatally Injured Drivers moreLikely to be Alcohol Related

Alcohol Related Drivers as Percent of Drivers Involved in Fatal Crashes By Their Survival Status




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0.01 - 0.09 g/dl 0.10 - 0.94 g/dl

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Killed Survived

Old Method – Allows for only two Alcohol Classifications for Drivers

with Positive BAC

Distributions of BAC for Drivers Involved in Fatal Crashes By their Survival Status (excluding

BAC=0)




0

0.25

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0.75

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1.75

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9

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7

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0.6

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0.8

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0.9

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BAC (g/ dl)

Perc

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Killed Survived

New Method – Allows for 94 Alcohol Classifications for Drivers with Positive

BAC

Distributions of BAC for Drivers Involved in Fatal Crashes By their Survival Status

(excluding BAC=0)




0102030405060708090

0.01 - 0.09 g/dl 0.10 - 0.94 g/dl

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Killed Survived

Old Method – Allows for only two Alcohol Classifications for Drivers

with Positive BAC

Distributions of BAC for Alcohol Related Drivers Involved in Fatal Crashes By their Survival

Status



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BAC (g/ dl)

Perc

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Killed Survived


BAC

Distributions of BAC for Alcohol Related Drivers Involved in Fatal Crashes By their

Survival Status




00.5

11.5

22.5

33.5

44.5

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0.0

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0.8

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BAC (g/ dl)

Perc

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Prior DWI None


BAC

Distributions of BAC for Drivers Involved in Fatal Crashes By Prior DWI Convictions

(excluding BAC=0)




QUESTIONS?

Documents

Session 38 Alcohol Data In The Fatality Analysis Reporting System (FARS)