Archive for December, 2012

Study Shows Field Sobriety Tests Overestimate Blood-Alcohol

Monday, December 31st, 2012

Proponents of the so-called “standardized” field sobriety tests (SFSTs) have long pointed to field studies which indicate a high correlation between performance on the tests and actual blood alcohol concentrations (BAC).  A new study now calls those conclusions into question.

Originally, the National Highway Traffic Safety Administration (NHTSA) paid a private group, the Southern California Research Institute, to conduct studies to find which among the various field sobriety tests used by police were most effective and to develop a standardized 3-test battery.  SCRI subsequently reported to NHTSA that a battery of walk-and-turn, one-leg-stand and nystagmus provided a strong correlation with breath test results.

Confronted with questions about those conclusions, NHTSA later commissioned the same researcher who had conducted the original studies, Marcelline Burns, to  corroborate the accuracy of her own findings.  Burns accompanied a small number of San Diego police officers conducting actual DUI investigations in the field.  After administering the SFSTs, the officers were asked to guess whether suspects had blood alcohol  concentrations (BAC) over or under .08%.   Burns reported a 91% correlation between SFSTs and BAC over-under estimates, arguably validating the battery of tests she had helped create.

A subsequent scientific article called Burns’ conclusions into question.  In Hlastala, Polissar and Oberman, “Statistical Evaluation of Standardized Field Sobriety Tests”, 50(3) Journal of Forensic Sciences 1, the raw data used in the validation study were obtained from NHTSA through the Freedom of Information Act.  The methodology used was then reviewed and the data subjected to statistical analysis.

The methodology was found to be seriously flawed in a number of respects.  For one thing, many of the suspects had very high BACs, making estimates of whether a suspect was over .08% obvious regardless of SFST performance.  For another, there was no attempt to isolate the influence of SFST performance from other factors:  officers estimated BACs after the field sobriety tests, but they also took into account earlier observations, such as erratic driving, slurred speech, odor of alcohol, flushed face, admissions as to amount of alcohol consumed, etc.

The most glaring defect in Burns’ corroborative study was that “all police officers  participating in the study were equipped with NHTSA-approved portable breath testing devices”.  In other words, the San Diego officers already had the results of portable breath tests when they were asked to estimate the BACs later obtained at the station!

After reviewing the flawed methodology, the raw data was then statistically analyzed.  The conclusions:

If we consider three ranges of MBAC [measured blood alcohol content], 0.00% to 0.04%, 0.04% to 0.08%, and 0.08% to 0.12%, the officers’ EBAC [estimated blood alcohol content] overestimated the MBAC 76%, 67% and 48% of the time, and underestimated it 14%, 26% and 28% of the time. 

In other words, officers relying upon field sobriety tests were far more likely to overestimate  BACs than underestimate — particularly with those suspects having low BACs. 

(T)he utility of the SFST depends very much on how intoxicated an individual is.  Accuracy (and specificity) are low when individuals are close to 0.08% MBAC, but if the individuals are quite intoxicated, such as above 0.12%, then accuracy is high.

In other words, in borderline cases involving persons at or under the legal limit, officers were very poor at estimating levels over .08% based upon SFSTs.  And it is these cases, of course, that are critical.  Suspects with high BACs are relatively easy to single out without the help of field tests; it is for the closer cases, particularly those who are innocent (below .08%), that the SFSTs are designed.  And it is with these very cases that the tests apparently fail. 

Put another way, accuracy in using field sobriety tests is high when they are not needed — and low when they are. 


Are “Sobriety Checkpoints” Really Constitutional?

Monday, December 24th, 2012

The Constitution of the United States pretty clearly says that police can’t just stop someone and conduct an investigation unless there are “articulable facts” indicating possible criminal activity….So how can they do exactly that with DUI roadblocks?

Good question. And it was raised in the case of Michigan v. Sitz (496 U.S. 444), in which the U.S. Supreme Court reviewed a decision of the Michigan Supreme Court striking down drunk driving roadblocks as unconstitutional. In a 6-3 decision, the Court reversed the Michigan court, holding that roadblocks were constitutionally permissible.

Chief Justice Rehnquist began his majority opinion by admitting that DUI roadblocks (akaDUI sobriety checkpoints”) do, in fact, constitute a “seizure” within the language of the 4th Amendment. In other words, yes, it’s a blatant violation of the Constitution. However….

However, it’s only a "minor violation", and there’s all this “carnage” on the highways MADD tells us we’ve got to do something about. The “minimal intrusion on individual liberties”, Rehnquist wrote, must be “weighed” against the need for and effectiveness of roadblocks. In other words, the ends justify the (illegal) means….aka, “The DUI Exception to the Constitution”.

The dissenting justices pointed out that the Constitution doesn’t make exceptions: The sole question is whether the police had probable cause to stop the individual driver. As Justice Brennan wrote,

“That stopping every car might make it easier to prevent drunken driving…is an insufficient justification for abandoning the requirement of individualized suspicion….The most disturbing aspect of the Court’s decision today is that it appears to give no weight to the citizen’s interest in freedom from suspicionless investigatory seizures”.

Rehnquist’s justification for ignoring the Constitution rested on the assumption that DUI roadblocks were “necessary” and “effective”.  Are they?  As Justice Stevens wrote in his own dissenting opinion, the Michigan court had already reviewed the statistics on DUI sobriety checkpoints/roadblocks:

“The findings of the trial court, based on an extensive record and affirmed by the Michigan Court of Appeals, indicate that the net effect of sobriety checkpoints on traffic safety is infinitesimal and possibly negative”.

p.s. The case was sent back to the Michigan Supreme Court to change its previous decision accordingly. But the Michigan Supreme Court sidestepped Rehnquist by holding that DUI checkpoints, if now permissible under the U.S. Constitution, were not permissible under the Michigan State Constitution! The Court ruled again in favor of the defendant — in effect saying to Rehnquist, “If you won’t protect our citizens, we will”. 


Guilty…of Not Being Average?

Friday, December 14th, 2012

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.

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.

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 term 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: The blood-alcohol level was declining and the rate of elimination is known. This second assumption involves the further assumption that the “burn-off” rate was .015 percent per hour (sometimes the assumed rate used is .02 percent). How does the prosecution know that the defendant was eliminating (assuming he was eliminating rather than absorbing) at that rate and not at .005 percent or .3 percent? 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. It's convenient: it makes prosecution and conviction much easier.


DUI Suspect Resisting Forced Blood Draw is Tasered, Dies

Saturday, December 8th, 2012

Maybe MADD's "War on Drunk Driving" has gone a bit too far….

D.A. Reviewing Death of West Allis Man After Taser Incident

Milwaukee, WI.  Dec. 6 — Prosecutors are investigating how West Allis police officers handled a drunken-driving suspect found dead the day after they used force and a Taser on him to obtain a blood draw…

The Milwaukee County medical examiner's office is awaiting autopsy results before determining a cause of death.  According to court and medical examiner's records:

Robert Wayne Maurina, 46, had come to the West Allis Police Department early on Nov. 28 to pick up his girlfriend after she was arrested on a drunken driving charge. Police suspected Maurina also was intoxicated and arrested him about 4 a.m. He was later charged with fifth-offense drunken driving.

At Aurora West Allis Medical Center, Maurina resisted attempts to take a blood sample, according to court records, and had to be restrained and stunned with a Taser.

Shortly before noon the same day, Maurina was released to his brother, in whose basement Maurina lived. The brother told a medical examiner's office investigator that Maurina had complained about pain to his ribs and kidney on his left side, and that he heard Maurina coughing about 7 p.m. that day.

The next morning, the brother said, he found Maurina dead in his basement room. The medical examiner's report indicated that Maurina was on several medications.

The funeral for Maurina, an Air Force veteran, was Tuesday…

No comment necessary.

(Thanks to John Kruzelock.)


Involuntary Intoxication

Monday, December 3rd, 2012

What if an individual drinks from a punch bowl at a party — not knowing that the punch has been secretly “spiked” by a prankster — and is later pulled over for DUI?  What if another person takes a medication prescribed by his doctor — without being told that it will cause impairment — and is subsequently arrested for driving under the influence of drugs?

Are these people guilty of DUI — or can they assert the legal defense of involuntary intoxication?

A no-brainer, right?  After all, a person should not be punished for something that was not their fault — that they weren’t even aware of. 

Not surprisingly, however, the courts in their infinite wisdom have taken contradictory approaches to these situations.  Some take the position that DUI is a “strict liability” offense, and so any mental element such as intent or even knowledge is irrelevant.  See, for example, State v. Pistole, 476 N.E.2d 366.  Others permit the involuntary intoxication defense only where the intoxication was caused by use of force or threat of force from a third party.  A few recognize the defense on the grounds that some mens rea (mental culpability) must exist in any crime.  See, for example, State v. Wallace, 439 N.E.2d 851.  And at least one likens a claim of involuntary intoxication to an insanity defense:  Did the defendant know the difference between right and wrong?  See Commonwealth of Pennsylvania v. Smith, 831 A. 2d 636. 

In those states which permit the defense, however, the prosecution need not prove that the intoxication was voluntary:  The defendant has the burden of proving by a preponderance of the evidence that it was involuntary — that is, he must prove his own innocence or stand convicted.