This research indicates that a driver with a BrAC of 0.05% is twice as likely to crash as a driver with no alcohol in their system, and the risk for a driver with a BrAC of 0.08% — the current legal limit in all states of the USA — is almost exactly four-times higher than with no alcohol.
What follows is an excerpt from the ‘Drug and Alcohol Crash Risk: A Case-Control Study’ (Executive Summary), from NHTSA (2017):
Alcohol Crash Risk Estimate
The unadjusted crash risk estimates for alcohol indicated that drivers with BrACs of .05 grams per 210 liters g/210L are 2.05 times more likely to crash than drivers with no alcohol. For drivers with BrACs of .08 g/210L, the unadjusted crash risk is 3.98 times that of drivers with no alcohol. When adjusted for age and gender, drivers with BrACs of .05 g/210L are 2.07 times more likely to crash than drivers with no alcohol. The adjusted crash risk for drivers at .08 g/210L is 3.93 times that of drivers with no alcohol. [#End]
Importantly, readers should also view the World Medical Association Statement on Alcohol and Road Safety (1992, 2006 & 2016), which states “…it would be desirable to lower the maximum permissible level of blood alcohol to a minimum, but not above 0.5 grams per litre, which is low enough to allow the average driver to retain the ability to assess risk.”
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Footnotes:
- “BrACs” are Breath-Alcohol Concentrations, as opposed to the more commonly seen Blood-Alcohol Concentrations [BACs].
- “0.5 grams per litre” is the equivalent of 0.05% BAC.