In many DUI cases, the breath evidence is the strongest evidence to be used in the case. The margin of testing error, and the fact that alcohol levels in the body are constantly changing means that no machine can ever be 100% accurate. However, there are certain procedures that are followed with breath testing devices that are used to attempt to make the measurement as accurate as possible.
Title 17 Breath Testing Requirements
To be used to properly establish breath alcohol levels at the time of driving, a DUI breath test must have all the following:
- The breath machine must have gone through the procedure to become one of the approved breath testing devices;
- The breath testing device must have a self-diagnosis hardware process to check internal device components to make sure that they are working properly;
- The device must measure the air temperature and record it when obtaining a breath test;
- The officer using the device must have been specifically trained in the device and how it works;
- The officer must have observed the testing subject for 15 minutes to make sure that the subject did not belch, burp, or vomit within 15 minutes of the test;
- The officer must also ask the testing subject after 15 minutes if the subject has belched, burped, or vomited within 15 minutes before the test;
- The machine must obtain enough air for a sample (to measure deep lung alveolar air rather than mouth air);
- The machine must obtain two test – one initial test, and another at least two minutes apart; and
- The two tests must agree within a .02% of each other, or the machine must take another sample two minutes later and see if the third or more test matches the previous test.
- The breath testing device must be maintained when required, and a log of maintenance and repairs must be kept;
- The breath testing device must be calibrated after x uses, or every x days, whichever comes first.
These procedures are highly important. The presence of mouth alcohol is a known problem with breath testing devices, and the 15-minute waiting period, the requirement of a sufficient sample, and the test timing of two minutes apart are efforts to avoid testing air from the mouth, where dental work, contaminants, food stuck in the teeth, or gum or mouth strips might affect the test.
A good lawyer that specializes in DUI defense will always check the maintenance and calibration records of the device used, to see if there are any problems. In hundreds of recent Orange County DUI cases, a breath machine used was found to not be properly calibrated, which resulted in a dismissal of the DUI case for each defendant.
If you find yourself needing a DUI lawyer, or have questions about a breath test in a DUI case and how that might help your case, please contact our office today. We can help you.