“Bad Calibration” Defense to a DUI

Driving under the influence (DUI) is a significant criminal offense in California, leading to serious legal and personal repercussions. One of the most common methods used by law enforcement to determine a driver’s blood alcohol concentration (BAC) is breathalyzer testing. However, the reliability of these tests can be compromised due to faulty testing procedures and improper calibration of the devices. The “bad calibration” defense is a crucial strategy for challenging DUI charges, centered on the premise that inaccuracies in testing equipment can result in false BAC readings. This article explores the legal basis, application, and challenges of the bad calibration defense in California DUI cases.

Legal Basis of the “Bad Calibration” Defense

The validity of breathalyzer results hinges on the assumption that the device used is accurate and properly maintained. California law mandates that breathalyzer devices must be regularly calibrated and maintained according to strict guidelines to ensure their accuracy. These requirements are codified in the California Code of Regulations, Title 17, Division 1, Chapter 2, which outlines the procedures for breath alcohol testing.

Key requirements include:

Regular Calibration: Breathalyzer devices must be calibrated at specified intervals to ensure accurate readings.
Proper Maintenance: The devices must be maintained in good working order and subjected to routine checks and servicing.
Certified Operators: Only individuals who have received proper training and certification can operate breathalyzer devices.

A failure to adhere to these standards can lead to inaccurate BAC readings, providing grounds for the bad calibration defense.

Application of the “Bad Calibration” Defense

To successfully employ the bad calibration defense, a defendant must demonstrate that the breathalyzer device used was not properly calibrated or maintained, resulting in an erroneous BAC reading. This defense involves several critical steps:

Obtaining Maintenance Records: Defense attorneys must request the calibration and maintenance records of the breathalyzer device used during the arrest. These records can reveal lapses in calibration schedules or improper maintenance practices.
Reviewing Calibration Logs: Analysis of the calibration logs can identify discrepancies, such as missed calibration dates or failed calibration checks, which undermine the reliability of the test results.
Cross-Examining the Operator: The defense can cross-examine the officer who administered the breath test to uncover any deviations from proper testing procedures or lack of certification.
Expert Testimony: Introducing expert testimony from forensic toxicologists or other experts can substantiate claims of faulty calibration and explain how these inaccuracies could lead to false BAC readings.

Case Law and Precedents

Several California cases illustrate the successful application of the bad calibration defense, highlighting its importance in DUI litigation.

In People v. Williams (1992) 3 Cal.App.4th 1326, the court emphasized the necessity of strict adherence to Title 17 regulations. The defense successfully argued that the failure to maintain proper calibration records cast doubt on the accuracy of the breathalyzer results, leading to the exclusion of the BAC evidence.

Similarly, in People v. Adams (1976) 59 Cal.App.3d 559, the court recognized that inaccuracies in breathalyzer devices due to improper calibration could result in false readings. The defense demonstrated that the device used had not been calibrated according to the prescribed schedule, leading to the dismissal of the DUI charge.

Challenges and Limitations

While the bad calibration defense can be compelling, it is not without challenges. Prosecutors will often counter this defense by arguing that any deviations from the calibration schedule were minor and did not significantly impact the accuracy of the results. To overcome these challenges, the defense must present strong evidence and expert testimony to substantiate claims of inaccuracy.

Proving Calibration Errors: The defense must conclusively show that the calibration errors were significant enough to affect the BAC reading. Minor deviations may not be sufficient to discredit the results.
Access to Records: Obtaining complete and accurate calibration and maintenance records can be difficult. Law enforcement agencies may be reluctant to provide these records, necessitating court orders or subpoenas.
Expert Testimony: Expert witnesses are crucial in explaining the technical aspects of breathalyzer calibration and its impact on BAC readings. Securing credible and persuasive experts can be challenging and costly.

Practical Considerations for Defense Attorneys

Defense attorneys must adopt a meticulous approach when preparing for a bad calibration defense. Key considerations include:

Thorough Investigation: Conducting a comprehensive investigation to obtain all relevant records and evidence related to the breathalyzer device used.
Collaboration with Experts: Working closely with forensic toxicologists and other experts to analyze calibration logs and maintenance records.
Strategic Cross-Examination: Developing a strategy for effectively cross-examining the arresting officer and any prosecution witnesses to expose flaws in the calibration and testing procedures.

Conclusion

The bad calibration defense to a DUI charge in California is a powerful tool for challenging the accuracy of breathalyzer results. By meticulously investigating the maintenance and calibration of the testing devices, defense attorneys can cast doubt on the reliability of the BAC readings and potentially secure favorable outcomes for their clients. Despite the challenges, this defense remains a viable and often successful strategy in the complex landscape of DUI litigation.

Citations

California Code of Regulations, Title 17, Division 1, Chapter 2
People v. Williams (1992) 3 Cal.App.4th 1326
People v. Adams (1976) 59 Cal.App.3d 559
California v. Trombetta (1984) 467 U.S. 479