Archive for January, 2011

Women and Breathalyzers

Monday, January 31st, 2011

If you are arrested for DUI and a breath test shows a blood alcohol concentration (BAC) of .08% or higher, you are presumed guilty. It does not matter, of course, whether you are a man or a women: the laws do not discriminate.

Maybe they should…

Researchers at the University School of Medicine in Trieste, Italy, have found that the stomach lining contains an enzyme called gastric alcohol dehydrogenase that breaks down alcohol, and that women have less of this enzyme than men.

To determine the relative effects of the enzyme, they gave alcohol both orally and intravenously to groups of alcoholic and non-alcoholic men and women. They found that women reached the same levels of blood alcohol as men after drinking only half as much.  With weight differences taken into account, they found that women reached BAC levels illegal in a DUI case after drinking 20 to 30 percent less alcohol than men.

The scientists’ conclusion: legislatures may need to consider sex differences in drunk driving laws when defining safe levels of drinking for driving motor vehicles. Frezza and Lieber, "High Blood Alcohol Levels in Women: The Role of Decreased Gastric Alcohol Dehydrogenase Activity and First-Pass Metabolism", 322(2) New England Journal of Medicine 95 (1990).

Yet another study has found that women have lower partition ratios of blood to breath. What kind of ratios? Well, all breath machines in DUI cases measure the amount of alcohol in a person’s breath. But the what we really want to know is the amount of alcohol in the person’s blood. So how do we get that? Simple: a small computer in the Breathalyzer multiplies the amount of alcohol it detects in the breath sample by 2100 times.

This is based upon the theory that, on average, there are 2100 units of alcohol in the blood for every unit of alcohol in the breath.  Of course, that’s only an average:  it varies from person to person.) According to the study, women have a significantly lower partition ratio. Jones, "Determination of Liquid/Air Partition Coefficients for Dilute Solutions of Ethanol in Water, Whole Blood and Plasma", Analytical Toxicology 193 (July/August 1983).  And the lower the partition ratio, the higher the reading — even though the true BAC does not vary. For example, a woman with a true BAC of .06% — below the legal limit — and a ratio of 1500:1 (rather than the presumed 2100:1) will get a reading on the machine of .09% — above the legal limit.

Put another way, the breath machine will show an average man accused of drunk driving to be innocent — but a woman with the same blood alcohol level to be guilty.

And then there’s the problem of birth control….

Scientists in Canada have found that "women taking oral contraceptive steroids (O.C.S.) appeared to eliminate ethanol significantly faster than women not taking O.C.S."  Papple, "The Effects of Oral Contraceptive Steroids on the Rate of Post-Absorptive Phase Decline of Blood Alcohol Concentration in the Adult Woman", 15(1) Canadian Society of Forensic Science Journal 17 (1982).

That means that women will reach peak BAC faster, and return to lower levels more quickly. This, of course, can create serious problems in a DUI case when attempting to estimate BAC at the time of driving based upon a breath test administered one or two hours later.

Making the problem worse, researchers have also discovered that women who were taking birth control pills or who were pregnant had higher levels of acetaldehyde on their breath, due to the decreased ability to metabolize the enzyme as the level of sex steroids increases.

So what?

Well, most breath machines use infrared analysis in measuring the breath sample of a DUI suspect. But these machines don’t really measure alcohol, rather they measure any compound which contains the methyl group in its molecular structure — and simply assumes that it is alcohol. And acetaldehyde is one of these compounds. Result: a higher "blood alcohol" reading on the Breathalyzer. Jeavons and Zeiner, "Effects of Elevated Female Sex Steroids on Ethanol and Acetaldehyde Metabolism in Humans", 8(4) Alcoholism: Clinical and Experimental Research 352 (1984).

It’s always a problem when the law, in its infinite wisdom, assumes that all of us are exactly the same.  (See How to Convict an Average Man)
 

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Close Enough for Government Work

Wednesday, January 26th, 2011

How crazy have things gotten in MADD’s "war on drunk driving"? 


Court: Key Enough for Drunk Driving Conviction

Boston, MA.  Jan. 25 — The state Appeals Court has ruled that someone who inserts a key in a car’s ignition and turns on the vehicle’s electricity without starting the engine can be convicted of drunken driving.

Robert S. McGillivary of Salisbury appealed his 2007 drunken driving conviction on the grounds that he was not operating the vehicle when an officer found him slumped over the steering wheel with the key in the ignition and the dashboard illuminated.

The court said Tuesday that turning the key is the first step in a sequence to set the vehicle in motion and "was sufficient to permit the jury to conclude that he ’operated’ the motor vehicle."


So…if you point a gun at someone, you’re guilty of murder?

There may be some logic to charging attempted drunk driving for putting a key in the ignition and then falling asleep, but it’s a corruption of the legal system to pretend that the crime actually took place.  

Unfortunately, this kind of legal and legislative corruption is common in the DUI arena.  See, for example, The DUI Exception to the Constitution.
 

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Driving Under the Influence of…Binaca?

Tuesday, January 25th, 2011

So you’re driving along and suddenly there are flashing red lights in your rear view mirror. You recall that glass of wine with dinner: not nearly enough to be over .08%, of course, but enough to cause an odor of alcohol on the breath. As you pull over, you grab the breath freshener and quickly spray it into your mouth. The officer asks you to step out of the car, holds out a portable breath testing device and asks you to blow into it. A moment later you are being handcuffed.

What happened? One of the many problems with breath machines is that they cannot tell the difference between alcohol coming from the lungs and alcohol which is already in the mouth or throat. This problem is referred to as mouth alcohol, and is particularly troublesome because, believing it to be alcohol from the lungs, the breath machines will incorrectly multiply the detected alcohol by 2100 times (see my earlier post, Breathalyzers — and Why They Don’t Work).

One common source of breath alcohol is breath spray, as well as mouthwash — both of which contain significant amounts of alcohol. Listerine, for example, contains 27% alcohol, Scope 19% and Astring-O-Sol 76%. Even a tiny amount of this on the breath or in the throat, if multiplied by the machine 2100 times, can result in high breathalyzer readings.

This was clearly illustrated in a study conducted with Listerine mouthwash on a breath machine and reported in an article entitled "Field Sobriety Testing: Intoxilyzers and Listerine Antiseptic", published in the July 1985 issue of The Police Chief . Seven alcohol-free individuals were tested at a police station, with readings of .00%. Each then rinsed his mouth with 20 milliliters of Listerine mouthwash for 30 seconds in accordance with directions on the label. All seven were then tested on the machine at intervals of one, three, five and ten minutes.

The results indicated an average reading of .43% blood-alcohol concentration — indicating a level that, if accurate, approached lethal proportions. After three minutes, the average level was still .20%, despite the absence of any alcohol in the system. Even after five minutes, the average level was .11% — well over the legal limit.

In another study, reported in 8(22) Drinking/Driving Law Letter 1, a scientist tested the effects of Binaca breath spray on an Intoxilyzer 5000. He performed 23 tests with subjects who sprayed their throats, and obtained readings as high as .81% — far beyond lethal levels. The scientist also noted that the effects of the spray did not fall below detectable levels until after 18 minutes.

Don’t spray and drive.
 

 

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How to Convict an Average Man

Wednesday, January 19th, 2011

One of the greatest sources of error in breath-alcohol testing is the consistently recurring fallacy that the individual tested is perfectly average in certain critical physiological traits. Put another way, obtaining an accurate blood-alcohol reading in a DUI case is completely dependent on the validity of a number of assumptions.

Unfortunately for the person being tested, these assumptions are usually incorrect: The person tested is rarely “average” in even one of these critical characteristics, let alone in all of them.

For example, all breath testing devices depend on the assumption that the ratio between alcohol in the exhaled breath and alcohol in the blood is 1 to 2100. In fact, the machine is designed to produce a reading based on that assumption; the accuracy of the reading is directly tied to the accuracy of the presumption. Yet, the actual ratio in any given individual can vary from less than 1:1300 to more than 1:3000. So a DUI suspect with a true blood-alcohol level of .07% but a breath-to-blood ratio of, say, 1:1500 would have a .10% reading on an “accurate” breath testing instrument.  In other words, the machine would show an innocent subject to be guilty.

Put simply, these machines do not test individuals. Rather, they test the same “average suspect” over and over again, but using the individual subject’s breath.

Another example of the assumption of “averageness” can be found in urinalysis. When a DUI suspect’s urine is analyzed for blood-alcohol, a presumption exists that there are 1.3 parts of alcohol in the bladder’s urine for every 1 part of alcohol in the blood. This 1:1.3 ratio is as fallacious as the 1:2100 ratio– that is, it is based entirely on the ratio found in the average person. In fact, however, the actual ratio found in any given individual can vary greatly. And as the ratio is in error, so will be the final blood-alcohol reading.

Yet another example of this constant reliance on averages shows itself when the prosecutor in a DUI trial offers evidence of so-called retrograde extrapolation — a fancy word for guessing backwards. The blood-alcohol level at the time of testing is not relevant to the charge, of course, and so the state will offer evidence to show what the level was when the defendant was driving. This is commonly done by “extrapolating” backward — that is, computing the earlier blood-alcohol level by estimating how much alcohol had been eliminated or “burned off” in the period between driving and testing.

But this requires two assumptions: (1) the blood-alcohol level was declining, and (2) the rate of elimination is known. This second assumption involves the further assumption that the “burn-off” rate was .015% per hour (sometimes the assumed rate is .02%). How does the prosecution know that the defendant was eliminating at that rate (assuming he was eliminating rather than absorbing) and not at .005% or .30%?

Quite simply, the prosecution does not know: It merely assumes that the defendant eliminates at the average rate. And, of course, error in such an assumption translates into error in the extrapolation.

This ever-present “average person” in the DUI arena is not limited to chemical analysis. We even find him with the arresting officer in the field. When the officer administers the nystagmus test (“follow my finger with your eyes”) as part of the battery of field sobriety tests, he operates on the assumption that the suspect is “Mr. Average.” The officer has been trained to “read” at what angle the suspect’s eyes begin jerking. If it begins before 45 degrees, the suspect fails. And where does the magic figure of 45 come from? The average person.

Don Nichols, a pioneer among DUI defense attorneys, would point out to juries that his client is female, Chinese and deceased — despite obvious evidence to the contrary. He then explains that statistically there are more women than men in the world, more Chinese than any other nationality and more dead human beings than living ones. Statistically, then, the average person is female, Chinese and deceased — and so, according to the prosecution, must be his client. He also asks the jury how many of them have 2.3 children – the average in the United States.

So why does the state presume facts that are clearly untrue? Simple: Since the prosecution doesn’t know anything about the defendant’s physiology, legally assuming the critical facts makes prosecution and conviction much easier.  
 

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Crackdown on…Bicycling Under the Influence?

Friday, January 14th, 2011

The latest in MADD’s "War on Drunk Driving"….


5 Bicyclists Arrested on Suspicion of DUI in L.A.

Los Angeles, CA.  Jan. 13
– Five bicycle riders have been arrested on suspicion of riding under the influence in South Los Angeles after officers gave sobriety tests to a pack of pre-dawn bikers.

California Highway Patrol Officer Travis Ruiz says officers were called to the Baldwin Hills area at around 1:30 a.m. Thursday after a bicycle lost control and crashed to the pavement.

Ruiz says while officers were there, 15 bicyclists came up to check on their friend. Ruiz says they were riding on both sides of the street without helmets and were barely visible to motorists.
 

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