Challenging the Breathalyzer in a California DUI Case

Posted by Jon Ibanez on September 20th, 2016

The breathalyzer is the most commonly used method for testing the blood alcohol content of suspected drunk drivers in California. Yet, both myself and Lawrence Taylor have written on more than a few occasions about the inaccuracies of the breathalyzer. Such inaccuracies include, but are not limited to an inability to differentiate between blood alcohol and “mouth alcohol,” elevated temperatures causing elevated BAC readings, and certain diets causing elevated readings.  

So can a person suspected of driving under the influence of alcohol in California challenge the accuracy of breathalyzers in court?

Notwithstanding the widely proven fact that breathalyzers are generally inaccurate, the California Supreme Court in 2013 ruled that scientific evidence refuting the accuracy of breathalyzers in general in California DUI cases are inadmissible.

The issue arose when a California trial court agreed with the prosecutor and excluded the testimony of a defense expert of Terry Vangelder who would have testified that breathalyzers, in general, can be inaccurate.

In 2007, California Highway Patrol pulled over Vangelder for allegedly going 125 miles per hour in San Diego. Although having admitted to consuming some alcohol, Vangelder passed field sobriety tests. Vangelder then agreed to a preliminary screening alcohol test (an optional roadside breathalyzer) which indicated that Vangelder’s blood alcohol content was 0.086 percent. Based on that, Vangelder was arrested and transported to the police station where he submitted to a chemical breath test (a required post-arrest breathalyzer). This breath test showed a blood alcohol content of 0.08 percent. Vangelder then submitted to a blood test which indicated that his blood alcohol content of 0.087 percent.

At trial, Vangelder called Dr. Michael Hlastala, a leading authority on the inaccuracies of breathalyzers.

"They are (inaccurate)," Dr. Hlastala testified before the trial judge. "And primarily because the basic assumption that all of the manufacturers have used is that the breath that [is] measured is directly related to water in the lungs, which is directly related to what’s in the blood. And in recent years, we’ve learned that, in fact, that’s not the case."

The judge however, did not allow the testimony and Vangelder was found guilty. Vangelder appealed and the appellate court reversed the decision in 2011. San Diego City Attorney, Jan Goldsmith, then appealed the appellate court decision arguing that such testimony would undermine Californi’s a per se law making it illegal to drive 0.08 percent blood alcohol content or higher.

Unfortunately, the California Supreme Court sided with Goldsmith.

“[T]he 1990 amendment of the per se offense was specifically designed to obviate the need for conversion of breath results into blood results — and it rendered irrelevant and inadmissible defense expert testimony regarding partition ratio variability among different individuals or at different times for the same individual," Chief Justice Tani Gorre Cantil-Sakauye wrote for the court. "Whether or not that part of expired breath accurately reflects the alcohol that is present only in the alveolar region of the lungs, the statutorily proscribed amount of alcohol in expired breath corresponds to the statutorily proscribed amount of alcohol in blood, as established by the per se statute."

The Court went on to say that, “Although  Dr. Hlastala may hold scientifically based reservations concerning these legislative conclusions, we must defer to and honor the legislature’s reasonable determinations made in the course of its efforts to protect the safety and welfare of the public."

I’m sorry, but I read that to say, “We recognize that science is important in determining the accuracy of breathalyzers, but we’re not going to undermine the legislature because of its good intent.”

Legislators are not scientists.

The effect of the decision was that people suspected of a California DUI can no longer offer evidence that breathalyzers, in general, are inaccurate. People suspected of a California DUI can, however, still challenge the accuracy of a particular breathalyzer.

Seems to me that the California Supreme Court doesn’t want accuracy in California DUI cases.

Share