Breathalyzer Calibration Issues: How They Might Help Your DUI Case

Recent developments created new possibilities for DUI defendants to challenge Breathalyzer evidence. A 2023 ruling from the Massachusetts Supreme Judicial Court invalidated 27,000 DUI cases due to calibration defects. This case represents the largest exclusion of breath test evidence in U.S. history. A similar scandal in New Jersey affected more than 20,000 DUI cases. These landmark cases established strong legal precedents that DUI defense attorneys can use.

If you have questions or concerns related to a DUI case, contact a DUI defense attorney near you. They can help build a strong legal defense based on the facts of your case.

In this article, we’ll cover factors that can impact the accuracy of a Breathalyzer test and how calibration issues can impact someone’s DUI case.

What Is a Breathalyzer?

A law enforcement officer may stop you if they suspect you’re driving under the influence (DUI) or driving while intoxicated (DWI). When this happens, they may ask you to take part in sobriety testing. This may include field sobriety tests, preliminary breath alcohol testing, and chemical testing.

During a traffic stop, an officer conducts a preliminary breath test with a handheld device called an alcohol meter, often called a breathalyzer or breathalysers.

“Breathalyzer”is a trademarked brand name, but the term is broadly used to describe all devices that use a breath sample to estimate someone’s blood alcohol concentration (BAC) level.

Courts regularly accept breath test evidence as sufficient proof of BAC levels. But while this type of measurement offers strong evidence about your BAC, it is not infallible. Law enforcement agencies must show that the testing device can produce reliable results.

In some cases, your DUI case may get dismissed if the state did not follow proper calibration procedures for the Breathalyzer device.

In most cases, however, law enforcement does not rely on the preliminary alcohol testers alone. This preliminary measurement gives the officer probable cause for arrest, but it isn’t often used in court. Officers will typically ask you to submit to further chemical testing at the time of arrest. Their purpose is to establish the blood alcohol content in your system and to look for illegal drugs.

Chemical tests may include providing blood, urine, or oral fluid for testing. You may also need to complete another breath analysis with a more sophisticated breath-testing machine.

Factors That Affect Breathalyzer Accuracy

Various factors could affect the accuracy of breath test readings. These include the person’s body physiology, humidity levels, altitude, and improper calibration service.

It is important to look into these factors affecting the accuracy of the breath test. For those accused of driving under the influence, they can act as grounds to challenge the evidence presented against you.

Physiological and Medical Factors

Individual health conditions can significantly impact the accuracy of a breath test. People with diabetes may experience diabetic ketoacidosis. This condition produces acetone in their breath, which can cause a Breathalyzer to show high results.

Those with gastroesophageal reflux disease (GERD) may also produce liquids and gases from their stomach that can affect readings.

Other people have health conditions that affect their breathing patterns. These conditions may cause unreliable alcohol readings in their breath samples.

Environmental Interference

Testing conditions may also play a key role in the accuracy of the results. Extreme temperatures can disrupt the chemical reactions inside breath testing devices, leading to false readings. High humidity levels can also interfere with breath samples.

These environmental factors are especially important to consider in regions with extreme weather conditions.

Timing and Contamination Issues

The timing of when you take a breath test matters significantly. Testing too soon after drinking can result in high readings due to the residual amount of alcohol in the mouth. There are also everyday products that can cause problems.

For instance, using mouthwash, breath fresheners, or certain medications before testing can contaminate the breath sample.

Pre-Test Observation Requirements

Most states require a 15-20 minute observation period before Breathalyzer testing. During this period, law enforcement should monitor the person accurately. They must ensure that the person under observation does not drink, eat, smoke, or do anything else that can affect the test’s accuracy.

State-Specific Testing Requirements

Some states provide specific requirements when conducting breath tests. For instance, in New Jersey, the state Supreme Court ruled in State v. Chun that women over 60 years of age should provide a smaller breath sample compared to those under 60. This is based on the findings that women aged 60 and above, in general, have a hard time providing breath samples.

Common Calibration Mistakes

Problems with Breathalyzer calibration have become the best way for lawyers to challenge DUI evidence in court. One of the most common mistakes that can help defendants is using machines past their required check-up dates.

How Often Should a Breathalyzer Undergo Calibration?

It depends. Each state has laws and standards about when and how breath-testing devices must undergo regular calibration. Often, the state should calibrate the device after several uses or at regular intervals. For an acceptable test result, most states follow these basic guidelines:

• The breath test must capture at least two measurable readings that are within 0.02% BAC of each other.
• The breath device must be on a conforming list of approved acceptable devices.
• The breath device must be properly maintained and checked for accuracy at regular, set intervals.
• The person administering the test is certified in the use of that particular device.
• The person administering the test must do so following their training.
• The person administering the test must monitor the test subject before testing begins. The subject cannot burp, regurgitate, eat, vomit, or smoke during this period immediately before the test.

In California, breath testing devices must be calibrated every 10 days or after 150 uses, whichever comes sooner. Improper recalibration or failure to maintain the machine can also affect its accuracy.

How Attorneys Can Challenge Breathalyzer Calibration Process

The most frequent challenge to breath test evidence focuses on one key question. Was the breath test device working properly when the test was given?

Breathalyzers and other breath testing devices need regular maintenance to deliver results accurately. An improperly calibrated or poorly maintained machine will produce unreliable results. These cannot form the basis of a presumption of intoxication under per se DUI laws.

Certain medical conditions and medications may influence your test results. Recent smoking or vomiting can contaminate your breath sample. Officers know these may impact the results and usually take precautions to prevent them.

A DUI criminal defense attorney can also focus on making their discovery request comprehensive. They can seek calibration-specific documentation and request important records challenging the accuracy of the Breathalyzer test.

Requesting Calibration Documentation

Discovery requests will target specific calibration records to expose potential device failures. They may seek calibration logs from the past 12 months before the test.

A DUI attorney can also help you obtain maintenance and repair records, operator training certification, and other calibration documentation.

Cross-Examination at Trial

Effective cross-examination exposes operator limitations and procedural violations. A DUI attorney will often focus on questions related to when the device was last calibrated and by whom. They may also consider health issues and environmental conditions, which could potentially affect the accuracy of the calibration method.

Example Cases

Below, we discuss landmark cases from two states that impacted the use of breath test evidence.

Massachusetts

In Commonwealth v. Ananias (2009), the defendant challenged the accuracy of an Alcotest 9510 breathalyzer test. Here, the court found that the Office of Alcohol Testing intentionally withheld 432 worksheets showing failed calibration tests. This created a conclusive presumption of unreliability for improperly calibrated devices.

As a result, the court excluded results from the entire period when the office used unreliable methodology.

In 2023, Commonwealth v. Hallinan led to one of the biggest breathalyzer exclusions in U.S. history. The Massachusetts Supreme Judicial Court ruled that between 2011 and 2019, the breathalyzers used by the state were not maintained and calibrated.

Around 27,000 people who were found guilty or pleaded guilty to drunk driving charges became eligible for plea withdrawals or new trials.

New Jersey

In 2024, the Supreme Court of New Jersey addressed the issue of improper breath analysis machine calibration in State v. Zingis.

The court found that faulty tests resulted in convictions of approximately 23,000 people between November 2008 and April 2016. State Police Sergeant Marc Dennis failed to follow proper protocol when calibrating Alcotest. This act adversely affected the reliability of the breath tests conducted. As a result, the state provided post-conviction relief to some of these individuals affected.

A DUI Defense Attorney Can Challenge the Breathalyzer Calibration in Your Case

Facing a DUI charge can be overwhelming. A DUI defense lawyer can help you navigate the system and provide valuable legal advice. They can look at the validity of your breathalyzer results and challenge the breath test calibration if necessary.