A Well Written Post on The Source Code Issue

I ran across an excellent post discussing the source code issue.  That is, the fight between criminal defense attorneys and the maker of the breath tester (CMI) to disclose the code used in their breath testers.  CMI will not allow an inspection of the code.  Consequently, it cannot be checked for accuracy.  CMI essentially tells everyone charged with DUI to "just trust us."

Ed Brayton, a journalist and the co-founder of Michigan Citizens for Science, discusses the source code litigation in Florida.

Here's a very interesting case from Florida, where an appeals court has upheld a lower court ruling that threw out evidence from a breathalyzer test in a drunk driving case because the manufacturer of the device refused to release the source code and allow defense experts to analyze the accuracy of the machines.

The results of breath tests in more than 100 local drunken-driving cases will not be allowed at trial, a judge announced Tuesday.

The validity of those breathalyzer tests has been challenged for more than three years because of the Intoxilyzer 5000, a machine that uses a breath sample to measure a person's blood-alcohol content.

Manatee County Judge Doug Henderson ruled two years ago that any Intoxilyzer 5000 tests were inadmissible in trial, but prosecutors appealed. On Tuesday, Henderson told lawyers that his ruling had been affirmed by the Second District Court of Appeal and Circuit Court.

Breath analysis machines are notoriously inaccurate and this has been a problem for a very long time. Dr. David Hanson, a sociologist who has written on this issue for decades, writes:

Breath analyzers (Breathalyzer, Intoxilyzer, Alcosensor, Alcoscan and BAC Datamaster are common brand names) don't actually test blood alcohol concentration (BAC), which requires the analysis of a blood sample. Instead, they estimate BAC indirectly. Different types of machine use different techniqes and larger machines generally yield better estimates than do hand-held models. Therefore, some states don't permit data or "readings" from hand-held machines to be presented as evidence in court. South Dakota does not even permit evidence from any type or size breath tester but relies entirely on blood tests to ensure accuracy and protect the innocent.

A major problem with some machines is that they not only identify the ethyl alcohol (or ethanol) found in alcohol beverages, but also other substances similar in molecular structure. Those machines identify any compound containing the methyl group structure. Over one hundred compounds can be found in the human breath at any one time and 70 to 80 percent of them contain methyl group structure and will be incorrectly detected as ethyl alcohol. Important is the fact that the more different ethyl group substances the machine detects, the higher will be the false BAC estimate.

The National Highway Traffic Safety Administration (NHTSA) has found that dieters and diabetics can have acetone levels hundreds and even thousand of times higher than that in others. Acetone is one of the many substances that can be falsely identified as ethyl alcohol by some breath machines.

One investigator has reported that alcohol-free subjects can generate BAC readings of about .05 after eating various types of bread products.

Substances in the environment can also lead to false BAC readings. For example, an alcohol-free subject was asked to apply a pint of contact cement to a piece of plywood and then to apply a gallon of oil-base paint to a wall. The total activity lasted about an hour. Twenty minutes later the subject was tested on an Intoxilyzer, which registered a BAC of .12 percent. This level is 50% higher than a BAC of .08, which constitutes legal intoxication in many states.

Similarly, a painter with a protective mask spray painted a room for 20 minutes. Although a blood test showed no alcohol, an Intoxilyzer falsely reported his BAC as .075.

Any number of other products found in the environment can cause erroneous BAC results. These include compounds found in lacquers, paint removers, celluloid, gasoline, and cleaning fluids.

Other common things that can cause false BAC levels are alcohol, blood or vomit in the subject's mouth, electrical interference from cell phones and police radios, tobacco smoke, dirt, and moisture.

Breath testers can be very sensitive to temperature and will give false reasings if not adjusted or recalibrated to account for ambient or surrounding air temperatures. The temperature of the subject is also very important. Each one degree of body temperature above normal will cause a substantial elevation (about 8%) in apparent BAC.

Many breath testing machines asume a 2,100-to-1 ratio in converting alcohol in the breath to estimates of alcohol in the blood. However, this ratio varies from 1,900 to 2,400 among people and also within a person over time. This variation will lead to false BAC readings.

Physical activity and hyperventilation can lower apparent BAC levels. One study found that the BAC readings of subjects decreased 11 to 14% after running up one flight of stairs and 22-25% after doing so twice. Another study found a 15% decrease in BAC readings after vigorous exercise or hyperventilaion.

Some breath analysis machinnes assume a hematocrit (cell volume of blood) of 47%. However, hematocrit values range from 42 to 52% in men and from 37 to 47% in women. A person with a lower hematocrit will have a falsely high BAC reading.

It's about time a judge took a stand on this issue.

Wonder Bread Does it Again!

It turns out my previous post showing Wonder Bread causing a false blood alcohol concentration reading was not an isolated incident.  The same forensic toxicologist and drug recognition expert did another Wonder Bread experiment.  Here it is:

 

Can Bread Cause the Intoxilyzer to Give a False Reading?

As demonstrated below, it appears that Wonder Bread is like Kryptonite to the Intoxilyzer 8000. While I cannot guarantee the accuracy of the test that occurred in this video, I have very little reason to doubt its veracity.  Especially since the manufacture of the Intoxilyzer 8000 (CMI) will not allow anyone (including the government) to inspect the source code used in this contraption.  Enjoy:

 

 

Judge Suppresses Use of DUI Breath-Test Evidence

Kim Smith of the Arizona Daily Star has reported that a Tucson City Court judge has ruled prosecutors cannot use the results of breath tests administered to 49 people scheduled to be tried before him on DUI charges. Her article states:

If other judges agree with Judge Thomas Berning, prosecutors could find it hard to prosecute thousands of other DUI cases locally and statewide. "I'm optimistic the other judges will agree with Judge Berning. It's a well-written decision," said defense attorney Joe St. Louis.  "This could be really big."

Last year, law-enforcement officers across Arizona began administering breath tests to suspected drunken drivers using a new machine called the Intoxilyzer 8000, St. Louis said. Almost immediately, defense experts realized the machines were sometimes providing "weird" or inexplicable results, St. Louis said.

In order to figure out what was going on, the experts said they needed to see the machines' "source card" or software. The software would also enable the experts to determine whether the results were accurate and reliable, St. Louis said.

 

 "It's a Sixth Amendment issue," St. Louis said. "Defendants have the right to cross-examine and confront their accusers." Defense attorneys began demanding the software from prosecutors, arguing they have a constitutional right to the information. Because prosecutors revealed they didn't have access to the software, Berning ordered the machine's manufacturer, CMI, to provide the software.

When CMI refused, defense attorneys filed a motion on behalf of 49 defendants asking Berning to dismiss their cases completely, suppress the results of the breath tests or assess monetary damages against CMI. Prosecutors told Berning the software is "proprietary" and can't be ordered disclosed, and the law doesn't allow for the evidence to be suppressed. They also argued they had given defense attorneys everything they had in their possession. Late last week, Berning ruled the results of the breath tests should be withheld from jurors.

Prosecutors will still, however, be able to provide jurors other evidence that could prove a defendant's guilt, such as the results of field-sobriety tests, St. Louis said. Although she can't comment on pending litigation, city prosecutor Laura Brynwood said she plans to appeal the judge's decision.

Challenging DUI Breath Testing: The Timing of the Pretest Deprivation Period

Arizona law enforcement often uses breath-testing devices to determine the blood-alcohol concentration (BAC) of a person suspected of DUI.  The Intoxilyzer 8000 is commonly used in Maricopa County.  When a person is suspected of DUI, he is generally requested to blow twice into an Intoxilyzer; this is referred to as “duplicate breath testing.”

The Department of Public Safety (DPS) has issued regulations for duplicate breath testing, which it defines as “two consecutive breath tests that immediately follow a deprivation period, agree within 0.020…of each other...”

In addition, the Department of Public Safety defines a deprivation period as “at least a 15-minute period immediately prior to a duplicate breath test during which period the subject has not ingested any alcoholic beverage or other fluids, eaten, vomited, smoked or placed any foreign object in the mouth.”  Breath-testing experts have stated that the deprivation period is critical to the breath-testing process. (See Kurt Dubowski, “Quality Assurance in Breath-Alcohol Analysis,” Journal of Analytical Toxicology, Vol. 18, October 1994.)
Commonly referred to as “quality assurance” measures, the DPS regulations seek to prevent any factors from affecting the breath sample.  Putting something in the oral cavity prior to the test could certainly change the results. Thus, law enforcement officials must prevent anything being put into a DUI suspect’s mouth prior to the breath tests.

When examining the breath test record, the starting and ending times of the deprivation period must be noted.  A 15-minute time span wherein a person does not put anything in his mouth is not sufficient; the deprivation period must “immediately” precede the first breath test.

The record must not show any gap between the deprivation period and the first breath test. Moreover, the police officer who conducted the deprivation period should be questioned. If he cannot account for any gap in time, then the test fails to comply with DPS regulations and may be inadmissible.

Scientific Defenses That May Be Available In Arizona DUI Cases

Challenging the reliability of a chemical test result is usually essential to effectively defending a DUI case.  In order to accomplish this task a thorough understanding is needed of the types of chemical testing used in Arizona and the scientific principals behind those tests. Here are the three types of chemical tests used by Arizona law enforcement:

  1. Breath Testing
  2. Blood Testing
  3. Urine Testing

Blood and breath testing are by far the most common.  Moreover, there is a trend in Arizona law enforcement moving towards blood as the primary testing method.  However, some police agencies such as the Department of Public Safety appear to be staying primarily with breath testing.  Urine testing is utilized mostly in cases where it is suspected that a person is under the influence of drugs.  Urine testing is seldom used in our state for blood alcohol testing.  Below is a summary the potential defenses for cases involving both breath and blood alcohol testing. 

BREATH TESTING DEFENSES

In order to know what defenses may be available to an attorney, an understanding of the breath alcohol testing process is required.  Breath testing is based on the scientific principal of Henry's law (also referred to as Henry's coefficient).  Henry's law was conceived by the English scientist William Henry. The principal provides in a closed container over time some of the molecules in a liquid will travel into the gas above the liquid. The amount of molecules that travel into the gas will be directly proportional to the number of molecules in the liquid.  Henry's law assumes a constant temperature and a closed system.  Consequently, all the factors that may influence Henry's law may also effect the results of a breath test.

The instrument used to apply Henry's law to breath testing is an Intoxilyzer.  In Arizona, most agencies now use the Intoxilyzer 8000.  The instrument is manufactured by a company named CMI.  The instrument is supposed to take a sample of the subject's lung air and use the principals of Henry's law to estimate a person's blood alcohol concentration.

Her are some of the challenges to evidentiary breath testing:

  • Range of Accuracy
  • Temperature Changes
  • Lack of a Deprivation Period
  • Radio Frequency Interference
  • Failure Keep Calibration Records
  • Partition Ratios
  • Lack of Warranty
  • Forced Agreement of Tests
  • Breathing Patterns
  • Mouth Alcohol
  • Hermatocrit Levels
  • Calibration Errors
  • Source Code Disclosure

 BLOOD TESTING DEFENSES

Similar to breath testing, blood testing also relies on the principals of Henry's law.  However, a different instrument is used to test the blood sample.  Most forensic laboratories use a headspace gaschromatograph.  Headspace refers to the space in a vial above the sample where the gas portion is located. Headspace analysis is the analysis of what is present in that gas. In its simplest terms, gas chromatography attempts to separate and identify what is in that head space gas. 

Some of the attacks that can be made on this blood testing process are:

  • Margin of Accuracy
  • Improper Tube Inversion
  • Chain of Custody
  • Contamination of Sample
  • Proper Site Cleaning
  • Lab Testing Errors
  • Expired Materials
  • Serum Samples
  • Failure to Follow Manufacturer's Instructions

While blood testing can be an accurate and precise measure of a person's blood alcohol concentration, it is not perfect.  Even under ideal conditions, there will still be a range of accuracy regarding test results.  However, conditions are not always ideal.  When basic scientific protocols are not followed the reliability of the test comes into question.