14 May 2009

The implications here are potentially HUGE.

For a long time I have maintained that convictions based on Breathalyzer™-type machines are suspect. When faced with criminal charges, the Constitution guarantees that you have the right to confront your accuser in court. How do you confront a machine? 
Moreover, how do you confront a machine that determines your blood alcohol level by extrapolating that information from measuring your breath alcohol level? And how do you confront that extrapolation when the manufacturers withhold the extrapolation code from independent examination citing "trade secrets"? 
Furthermore, the metric doesn't actually measure intoxication because intoxication is determined by a number of issues including an individual's personal alcohol tolerance, body mass, hematocrit percentage, gender, race, etc. If you're diabetic, have acid reflux, gum disease, dentures, a small woman, or eat a low-carb diet, you'll score artificially high. What's more, these instruments make an abundance of calculations based, not on the individual tested, but on presumed averages — your size is average, your breathing is average, etc. Oh, and it also assumes that in the past day or so you haven't inhaled any solvents or other vapors with methyl compounds like gasoline, glue, or paint — which will falsely register as booze.
When folks first started drafting DWI laws, they went to the American Medical Association to inquire what blood alcohol percentage would impair an "average" person. After extensive testing, the AMA determined it was .15. Over the years, via political pressure primarily from MADD, that number has been cut by almost half. Essentially, legislators have accepted an arbitrary number — .08 in  most states — and fashioned it a one-size-fits-all determination of "impaired." It's not unlike a legislature adopting 150 lbs. as officially "fat."
If you refuse to submit to testing out of concern for scoring a false positive, you're basically deemed automatically guilty — despite the presumption of innocence and the Fifth Amendment guarantee that the state cannot compel self-incrimination. 
Holy hell. Conviction on this basis is just kafkaesque.
So I was interested to note that New Jersey addressed the question, "Are alcotest instruments scientifically reliable for establishing blood alcohol levels in prosecutions?" in the case of State v. Chun. The instrument was the Alcotest 7110, called by its manufacturer "the single best microprocessor-driven evidential breath tester on the market." The defense attorneys spent two years trying to get the instrument's source code. They finally got it and had it analyzed. Money quotes from the analyst:
"Base One...did an extensive evaluation, finding 19,400 potential errors in the code"
"the patchwork code...is not written well, nor is it written to any defined coding standard"
"The Alcotest Software Would Not Pass U.S. Industry Standards for Software Development and Testing"
"Sections of the original...and modified code show evidence of using an experimental approach...or use what is best described as the 'trial and error' method. Several sections are marked as 'temporary, for now'"
"Readings are Not Averaged Correctly"
"This is a loss of precision in the data; of a possible twelve bits of information, only four bits are used"
"Catastrophic Error Detection Is Disabled"
Really? We're using this technology as evidence to convict people of felonies
This case is on my radar. Stay tuned.

1 chimed in:

william said...
This comment has been removed by a blog administrator.