Breath test science:how California courts ignore it
The California Supreme Court recently eliminated several important breath test defenses for DUI cases that DUI attorneys Los Angeles used to successfully defend DUI charges.
PARTITION RATIOS AND VANGELDER (58 Cal 4th 1)
According to the 2013 Supreme Court of California decision in People v. Vangelder, partition ratios cannot be argued to a jury. Before this case, Los Angeles DUI defense attorneys would argue that breath sample results are not the same as the blood sample results because the ratio of alcohol in blood could be very different from the ratio of alcohol in breath samples. In the case of Mr. Terry Vangelder, he was prosecuted for a DUI after he was pulled over for speeding and his breath alcohol test showed a result of .08 % BAC. Mr. Vangelder defended his DUI at trial where a DUI defense attorney tried to introduce the testimony of Dr. Hastala who testified that breathalyzers don’t accurately show the level of alcohol in blood because scientific research shows that the ratio of alcohol in the air in the lungs varies when compared to the ratio of alcohol in the blood. Therefore, it is not scientifically accurate to assume that a .08 % BAC in breath is the same as a .08% BAC in blood. This is based on various factors that influence the ratio of alcohol to breath and therefore breathalyzers are not as accurate as many believe. The California Supreme Court held that because the legislature assumed breathalyzers are scientifically accurate, the defendant cannot challenge his DUI conviction even if they are using scientific research! This Supreme Court decision is contrary to science so now these legitimate “partition ratios” scientific arguments cannot be used in Los Angeles DUI defense.
Under California Vehicle Code section 23610, breath results are based on a ratio of either .08 grams of alcohol per 100 ml of blood or .08 grams of alcohol per 210 liters of breath. Because a person cannot breathe out 210 liters, the breathalyzers are designed to take 1.5 liters of breath for a sample. Once a person breathes out 1.5 liters, the breathalyzer multiplies the number of grams of alcohol it senses in a breath sample by 140 to get to 210 liters. Because the amount of alcohol in the blood is proportional to the amount of alcohol in the breath, it is possible to convert the breath alcohol to blood alcohol. Legally this ratio is fixed at 2100. However, this is not reflective of science because each person’s concentration of alcohol in their blood will not be the same as the concentration of alcohol in their breath. The difference has to do with physiological differences, with each person’s blood being slightly different with the ratio (partition rations) ranging from 1600 to 2400. But, the court does not allow DUI defense attorneys to go into the partition ratios anymore, and now, once the machine calculates the grams in 1.5 litters to be more than .08 grams, you are over the limit and will be arrested for a DUI in Los Angeles. Prior to the Vangelder case a Los Angeles DUI attorney could argue that because each person is different, a .08 BAC in breath may be .07 BAC in blood, thus getting a “not guilty” verdict in a DUI trial.
California Vehicle Code 23610
California Vehicle Code section 23610 permits the introduction of evidence disputing that a person is over the limit. In subsection (c), VC 23610 allows the introduction of evidence disputing impairment. Yet, the California Supreme Court decided not to allow the defense to challenge any breathalyzer’s results because of the partition ratio. It is clear to Los Angeles DUI Attorneys that the Supreme Court was wrong to decide the Vangelder case this way.
Reliability of Breath Tests in Los Angeles DUI Cases
Breath tests are inherently inaccurate as a measure of how much alcohol a person has in his blood. The reason for this inaccuracy is that breathalyzers are manufactured on the assumption that the amount of alcohol in the air in the lungs is directly related to the amount of alcohol in the blood. This assumption is based on research from the 1950s. Recent research disputes that conclusion and shows that the ratio of alcohol in the lungs’ air to alcohol in the blood is not constant. The speed of breathing, depth of breathing, body temperature, breath temperature, the ratio of red blood cells to total blood volume, gender, etc affects it. For women, because they have smaller lungs the concentration of alcohol in the lungs can be higher. Also, some medical conditions can affect the ratio of alcohol in the breath to blood. All of the above reasons are important in DUI defense and will change the blood alcohol level (and not the breath alcohol level which is an approximation of the blood alcohol level). Lastly, because mucus membrane and mucus cover the entire distance the air travels to the lungs, absorbing alcohol and contributing to the increased alcohol level in a breath test. Yet, according to the Supreme Court, the deficiencies in the design of breathalyzers that cannot account for all changes in the breath alcohol level must be ignored despite science proving that speed of breathing, depth of breathing, body temperature, breath temperature, the ratio of red blood cell to total blood volume, and sex of person can cause the partition ratio to fluctuate (and therefore give a wrong breath test blood alcohol level).
The Supreme Court only permitted arguments in DUI trials showing the presence of mouth alcohol or arguments showing that the breathalyzer was not properly used. Los Angeles DUI attorney can still argue around Vangelder’s holding by pointing out for example that proper administration of breathalyzer test needs to be done in the post-absorptive phase. Thus, failure to realize
if the person was in a post-absorptive phase when administering the breathalyzer test can help DUI defendants in Los Angeles.
FACTS OF PEOPLE V. VANGELDER 58 CAL 4th 1 
Defendant Terry Vangelder was tried in San Diego for a DUI. At his trial, the jury was deadlocked and could not reach a verdict on the California Vehicle Code 23152(a) charge. However, the jury convicted Terry Vangelder of California Vehicle Code 23152(b), over .08% BAC violation. The VC 23152(b) conviction was based on breath sample results that Terry Vangelder gave to the police upon request. The results were another count based on PAS (preliminary alcohol screening) and EC/IR (electrochromatography/infrared) results that showed his blood alcohol level to be equal to or above .08 percent alcohol.
Mr. Terry Vangelder appealed his conviction and the Court of Appeals reversed the conviction. The Government appealed the Court of Appeals ruling to the California Supreme Court. The California Supreme Court then reversed the Court of Appeal ruling, reinstating the conviction and prohibiting DUI defense attorneys from challenging the partition ratios, and held that every person’s blood alcohol level conversion rate was 2100:1 despite science showing otherwise.
The science behind assuming that any person’s blood-to-alcohol concentration is the same as breath-to-alcohol concentration is based on a study by the National Traffic Safety Administration in which the rate was measured at 2100:1.
This decision is very damaging to previously used Los Angeles DUI attorneys’ arguments that breath tests are inaccurate because the conversion ratios are slightly different for each person. Some person’s breath to alcohol will convert at 1:210, for others it will be 1:2150 for yet another it would be 1:2050. This difference is especially important for low blood alcohol cases, where such difference can put a defendant below the limit of .08 percent
If you are charged with DUI in Los Angeles, please contact our office to talk directly to Los Angeles DUI lawyer. We can provide quality representation at an affordable price. You can call our office at (818) 921 7744.
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