DUI Defendants May Challenge Breath Tests, Court Rules

The California Supreme Court has made a recent ruling that California drunk driving defendants in should be able to challenge breath test results in court. According to an Associated Press news report, the court is basically allowing defendants to question the science of breath tests, which use a standard formula called “Partition Ratio” to convert the amount of alcohol vapor in the lungs into a blood alcohol level.

The problem with this science is that breath-to-blood ratios vary greatly throughout the population and from person to person, depending on factors such as body temperature, atmospheric pressure, medical conditions and the precision of the measuring device. What this means is that the same breath test result for one person’s breath could erroneously signal intoxication while for another it could mean that they simply had a glass of wine with their dinner.

The recent California Supreme Court ruling opens the door to breath test challenges, an option that has remained closed to most DUI defendants over the last two decades. The court said in its ruling that evidence of the variability of these tests can henceforth be shown to juries. This ruling confirms what any DUI defense lawyer already knows – that one-size-fits-all breath tests don’t tell the real story for all suspects.

If you have been accused of drunk driving in Los Angeles, Orange or Ventura counties, it is critical that you consult with an experienced Southern California drunk driving defense attorney at Sitkoff & Hanrahan. We have successfully challenged breath, blood, and field sobriety tests on our clients’ behalf. We will fight hard to protect your rights and make sure your DUI case has a positive outcome.