Tuesday, March 15, 2011

Breathing patterns can affect breath test results

A recent scientific article from Forensic Science International confirms something that Seattle DUI lawyers already know, that breathing patterns can affect the result of a breath test in a big way. In "Influence from breathing pattern on alcohol and tracer gas expirograms—Implications for alcolock use", the Swedish authors conclude from their studies that the measurement of a breath alcohol result is greatly influenced by the timing of the test and the breathing pattern of the person taking the test. Specifically, shallow breathing or hyperventilation can lead to a lower breath test result. Conversely, deep breathing and holding the breath before blowing can lead to an increased breath test result.

There are a couple of points to be made here. First, the machine is supposed to be giving us an accurate measurement of what a person's actual breath alcohol content is. It should not be too high or too low based on how the person is breathing, especially since everyone breathes differently, and people who have been arrested are often crying, in shock, angry, etc, and not breathing in their normal breathing pattern. This is more proof that the number that the machine spits out is just a “guesstimation,” at best.

Second, police officers that know this information can use it to manipulate test results (just as a subject could). I am able to obtain and watch a video recording of the breath test in almost every Seattle DUI case, which I handle. It is very common to see police officers demonstrate to the subject to how to take a deep breath and hold it, before blowing in the machine. Whether the officer realizes that this can influence the test result, I don't know. But, it is very, very common. If nothing else, taking a deep breath and holding it tends to heat up the breath to be expired. The machine is calibrated to assume that the expired breath is 34 degrees Celsius +/- .2c. 34 degrees Celsius is 93 degrees Fahrenheit. The human body is, on average, at a temperature of 98.6 degrees Fahrenheit, or 37 degrees Celsius. Expired breath is expected to cool as it leaves the human body, thus the assumption of the lower temperature by the breath test machine. However, if the breath is warmer than 34 degrees Celsius, the test result will be skewed higher. Holding the breath will make it closer to the 37 degrees Celsius of the human body when it is expired.

The bottom line is that there are dozens of variables that can affect what the breath test result is at any given moment. These variables include breathing patterns, body temperature, partition ratio between the breath and blood, inherent margins of error in the machine, the inherent margin of error in the gas or solution used to calibrate the machine, burping, crying, hyperventilating, interfering chemical compounds, voltage fluctuations in the power supply to the machine, radio frequency interference from police radios, cell phones, etc. Every person's biology is different, but the machine treats everyone as if they were the same. Every person's breathing pattern is different, but the machine assumes that everyone is breathing the same. Alcohol in the blood is what makes people intoxicated, not alcohol in the breath. The machine has to make assumptions about the breath, and calculations and conversions based on those assumptions to estimate what the blood alcohol content is. The assumptions and estimates these outdated machines make leave too much reasonable doubt in my opinion as to what a persons actual blood alcohol level is and whether they are actually guilty of a Seattle DUI.  

Thursday, March 3, 2011

Field Sobriety Test FAQs and other thoughts

Lately I have had several potential clients accused of DUI meet with me and have some interesting issues with the Field Sobriety Tests or FSTs for short.  The purpose of this article is to kind of clear the air on people’s misconceptions about these tests, whether you should take them, and how accurate they are.The FSTs are a battery of tests that police officers will ask that you complete, usually while on the side of the road, when investigating for DUI, so they can “make sure you aren’t too impaired to drive.”  These tests are completely voluntary and you have the option to decline them.  Since they are voluntary.  Don't do the Field Sobriety tests!  Let me repeat, don’t do these tests, I cant tell you how many former clients I have still do these tests.  Remember they don’t satisfy any court requirement and they usually only incriminate you further on your DUI

So what are they?  There are 3 main SFST’s that are employed by most of the law enforcement agencies in Washington State when investigating a DUI

1.  The first is one of the most well known among civilians – the officer waiving a pen in front of your face and telling you to follow it with your eyes. This test is known as Horizontal Gaze Nystagmus (HGN). The officer will slowly move a stimulus (usually a pen) in front of your eye (right to left, or left to right) to determine whether your eyes are able to track the pen in a smooth manner (checking for nystagmus – an involuntary jerking of your eyes).

2.  The second test that will usually be asked to complete is the Walk and Turn. The officer will have you stand in a starting position while you are listening to his instructions. You will then take 9 heel-to-toe steps, turn and take 9 heel-to-toe steps back to the start line. This is considered a “Divided Attention” test (i.e you will need to concentrate on two things at one – listening to directions while maintaining the start position but not actually starting).

3.  The last of the SFST’s is the One Leg Stand.  Here the officer will have you maintain a start position while explaining the directions (another “dividend attention” test). Once the officer instructs you to begin, you will raise one leg approximately 6 inches off of the ground with your foot pointed out and count out loud (one-one-thousand, two-one thousand, three-one thousand) until they tell you to stop.  Which is supposed to happen after 30 seconds. 

Now there are some other field sobriety tests that can be requested of you, usually Seattle Police Department Officers will request you complete these tests in addition to the main three.  Typically you will see these from some of the members of the DUI squad.  

The other field sobriety tests include:
·       Add 20 + 21
·       saying ABC’s (not singing),
·       counting backwards between two numbers,
·       finger dexterity (finger to nose),
·       Romberg Test (you stand still with feet together, arms at sides, head back, and eyes closed – the officer will check for swaying).

So how accurate are these field sobriety tests?  Well there was some studies done by the National Highway Traffic Safety Administration back in the late 70’s and early 80’s.  Beginning in late 1975, the Southern California Research Institute under the guidance of NHTSA traveled to law enforcement agencies through the US to select the most commonly used field sobriety tests.  Six tests were used in the initial stages of this study.

Laboratory research indicated that three of these tests, when administered in a standardized manner, were a highly accurate and reliable battery of tests for distinguishing alcohol levels about 0.10.  NHTSA analyzed the laboratory test date and found: HGN, by itself, was 77% accurate; WAT, by itself was 68% accurate, and OLS, by itself was 65% accurate.  When HGN and the WAT were combined an 80% accuracy was achieved. 

Now let me preface these results for a minute.  These tests were conducted in controlled environments.  Meaning they were done indoors, on a level surface, with good lighting, and performed by people with nothing to lose.  This is what most police officers, and prosecutors don’t understand.  When a person is on the side of I5, with cars speeding by them, its 20 degree outside, the officers overhead lights on blinking, they are scared and never been in trouble before, facing the strong likelihood of going to jail.  Obviously this is going to affect how a person does on these roadside gymnastics tests.  Imagine taking a test in school, and if you didn’t get a “B” you would go to jail.  That’s a lot of pressure if you ask me.  In addition to that these tests in my opinion are nothing but junk science.  But that’s for another blog. 

In summary, remember to talk to an attorney before you do these tests.  If you have had alcohol to drink, and the police officer smells an odor, chances are you’re going to get arrested for a DUI.  Regardless if you do these tests are not.  So you might as well make things easier on yourself, and your DUI Attorney and politely decline.  If at any time you ever have a question when you’re being investigated by a police officer always ask to speak with an attorney.  Seriously.  You can call me anytime.  24/7.  I will always pick up.  Or you can ask to speak with a public defender.  Usually police officers have that number on speed dial.