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Women's Issues in DUI Breathalyzer

Did you know that California DUI breathalyzer's do not give an accurate measurement of a woman's blood alcohol content? In fact, a woman who has an actual blood alcohol content of .07% - below the legal limit - may test 0.10% on a California breathalyzer. Learn why in this article.

Breath machines assume that for 2100 units (milliliters) of air will contain the same amount of alcohol as 1 unit (milliliter) of breath. This is known as a partition ratio, and the formula is expressed as 2100:1. Unfortunately, this is an average that does not exist in most of society, and certainly not in most women. In reality, very few people will actually have a 2100:1 ratio.

The 2100:1 average is a number agreed upon by the National Safety Council's Committee for Tests on Intoxication in 1952. Even at the time, that number was highly disputed. R.N. Harger was on that committee, and just so happened to have invented a device that used the 2100:1 ratio in calculating BrAC results.

Later research by Kurt Dubowski - a leading expert in intoxication testing for the government - found that the actual number ranges from between 1100:1 up to 3000:1 among the general population. A South Dakota Court held in State v. McCarty, 424 N.W.2d 67 (S.D. 1988), that the "ratio can vary as much as "1141 to 1 to 3478 to 1..." Medical science supports the conclusion that women typically have a lower partition ratio than men.

What does is matter?

Edward F. Fitzgerald noted in Intoxication Test Evidence, Second Edition, that "All breath test devices, for example, will report a 0.10% for a subject who has a true BAC of 0.07% if he or she has a partition ratio of 1500:1 (instead of 2100:1), and conversely, a 0.10% for a subject who has a true 0.14%, if he or she has a partition ratio of 3000:1."

So, if your partition ratio is lower than the 2100:1 assumed by the machines, then the machines will measure your BrAC as higher than your actual BrAC. If your partition ratio is higher than 2100:1 then the machines will measure your BrAC as lower your actual BrAC. And, guess which gender typically will have a partition ratio lower that 2100:1?

Yep! Since women are typically smaller in stature than men, they typically have a lower partition ratio. Thus, a woman's breath alcohol reading will unfairly measure her BrAC higher than her male counterpart's BrAC simply so the government has an easy way of testing DUI suspects.

Come back to read more in the coming week about how women are treated unfairly by the California DUI breath machines. We will expose other factors that will cause false readings by the machines, and talk about how we use these factors when handling California DUI cases. In the meantime, go to our Facebook page and tell us what you learned from this post, and ask us any questions you may have.