Wisconsin Department of Transportation

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Drunk driving risk factors

Alcohol concentration

Even at an Alcohol Content (AC) level as low as 0.04%, alcohol in your blood system affects driving ability and crash likelihood, according to Special Report 216, "Zero Alcohol" by the Transportation Research Board.

  • The probability of a crash begins to increase significantly at 0.05 AC and climbs rapidly after about 0.08%.
  • For drivers with AC's above 0.15% on weekend nights, the likelihood of being killed in a single-vehicle crash is more than 380 times higher than it is for non-drinking drivers.


Alcohol-related crashes in Wisconsin are much more likely to involve men than women.

  • Among fatally injured male drivers in the year 2008, 37% of those tested had AC's of 0.08% or more and women tested for .08 or above were 29%. These numbers are taken from all of the fatalities that were tested.
  • Men, ages 21-24, are the most likely drivers to be killed in a crash when their blood alcohol content is above 0.08.


Male drivers ages 21-40 make up the majority of fatally injured drivers with high ACs. This group has shown only a modest decline in the 1980s in the percentage of fatally injured drivers with high ACs.

In contrast, other age groups, particularly teenagers, show substantial declines. Drivers in the 16-20 year-old group showed the biggest improvement throughout the 1980s, due largely to the 21-year-old alcohol purchase laws.

Wisconsin Driver Age and Crash Involvement 2008
Age Total Number
in Crashes
Number Who Had Been
Drinking in Crashes
Unknown 18,659 9.0% 25 0.3%
14 and under 113 0.1% 6 0.1%
15 to 19 23,653 11.5% 614 8.5%
20 to 24 26,256 12.7% 1,721 23.8%
25 to 44 70,634 34.2% 3,258 45.0%
45 to 64 51,787 25.1% 1,455 20.1%
65 to 84 13,797 6.7% 152 2.1%
85 and up 1,334 0.6% 4 0.1%
Totals 206,233 100.0% 7,235 100.0%

Questions about the content of this page:
Colette Brown, Colette.brown@dot.wi.gov
Last modified: January 15, 2014

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