Breathalyzer tests can be challenged, Calif. Supreme Court rules
The California Supreme Court made it easier today for persons accused of drunk driving to challenge the results of breathalyzers.
The state high court ruled unanimously that defendants can present evidence to show that the breathalyzer results failed to accurately reflect the amount of alcohol in the driver's blood.
A suspected drunk driver can choose either to submit to a blood test, which measures the amount of alcohol in the blood, or a breath test. A breath sample must be converted mathematically to derive a blood-alcohol percentage.
The conversion factors can vary widely, "both in the general population and within an individual," the court said.
A driver's ratio of breath-alcohol to blood-alcohol concentration can be influenced by body temperature, medical conditions, sex and the precision of the measuring device.
Whereas experts say the standard ratio used to derive a blood-alcohol concentration from breath approximates or even underestimates the amount of alcohol the driver consumed, they also agree that breathalyzer results may not always accurately show an individual's intoxication.
"Evidence casting doubt on the accuracy of the breath-to-blood conversion ratio is just as relevant as other evidence rebutting the presumption of intoxication from a breath test result, such as evidence that the defendant had a high tolerance for alcohol or performed well in field sobriety testing, Justice Carol A. Corrigan wrote for the court.
-- Maura Dolan








This changes everything in regard to DUI defense!
Posted by: Walter | July 09, 2009 at 12:09 PM
It can be influenced by sex?
Yes, please!
Posted by: Internet Joe | July 09, 2009 at 01:29 PM
I wasn't drunk. I swear to God, I only had one beer.
Posted by: Schigolch | July 09, 2009 at 01:29 PM
About 15-years ago the legal limit for DUI was amended to include breath results as a separate thing. The breath level is 0.08 Grams of alcohol per 210 liters of breath. The blood level is 0.08 grams of alcohol per milliliter of blood. They are different, no conversion is necessary to satisfy the charge. There is sufficient scientific evidence to show that if a person blows 0.08 they are under the influence regardless of their blood level. This has been the law for quite some time.
Posted by: Scot | July 10, 2009 at 09:00 AM
Scot you obviously missed the point of this article. It was saying even if the breathalyzer shows a .08 it could be wrong.
Posted by: GG | December 29, 2009 at 11:04 AM
I really don't find it that surprising myself, breath been something that can be altered with the simplest of food, like what happened to a man in Australia whose In-Car Breathalyzer "failed" and didn't allow him to start his car after he ate some ice cream. At least with the blood test we can rest assured that only the people who deserved it will end up with the fine or jail sentence.
Posted by: Carlos | January 15, 2010 at 02:40 AM