Chicago DUI lawyer comments on new breath testing case

Finally. We all know machines can malfunction. We know that everyone doesn't respond the same way to medicine. We also know that sometimes test results are wrong, right? The California Supreme Court has ruled that breath tests don't always mean someone is intoxicated even if the result is above the legal limit of .08, People v. Timmie Lance McNeal, S157565.

July 9, San Francisco, CA

Accused drunk drivers now have more ammunition for challenging Breathalyzer findings as a result of a unanimous ruling Thursday by the California Supreme Court.

The ruling is expected to make drunk-driving cases more complicated and possibly more difficult to prosecute, lawyers said. Courts in two other states, Arizona and Vermont, have reached similar conclusions.

Under the law, a suspected drunk driver can submit to either a blood test, which measures the amount of alcohol in the blood, or a breath test. Alcohol levels in a breath sample are converted mathematically to derive a blood-alcohol percentage. In California, a person is legally drunk when his or her blood-alcohol level is 0.08% or higher.

The standard formula for converting breath results to blood-alcohol levels is not accurate for everyone, however, and can vary depending on an individual's medical condition, gender, temperature, the atmospheric pressure and the precision of the measuring device, the court said.

"The question is whether a defendant who has a blood-alcohol concentration of 0.08% or more measured by breath is entitled to rebut that presumption that he was under the influence" in certain cases, Justice Carol A. Corrigan wrote. The court's answer was yes.

Even though experts say the standard ratio used to derive a blood-alcohol concentration from breath generally approximates or even underestimates the amount of alcohol the driver consumed, they also agree that Breathalyzer results may sometimes overestimate the amount of alcohol in the blood.

Thursday's ruling permits defendants in some cases to challenge those results based on mathematical ratios.

"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," Corrigan wrote.

The situation currently is that juries are led to believe that when a person blows into the breath test, the blood-alcohol measure that breath test gives is a fact, when all a breath test is is a measure," Popper said.

I wonder how long it will be before this California decision becomes a standard ruling throughout the country. It's time to put common sense back at the forefront, of course a breath test can't tell the entire story for every single person, no matter what the number is. There are simply too many variables that impact the measure of alcohol based on a breath test.