Defense Casts Doubt on Breathalyzer, DUI Charges

• Not Guilty Despite a Breath Test Twice the Legal Limit – Police claimed the client blew nearly twice the legal limit and failed sobriety tests, but Attorney Lown exposed flaws in the investigation and secured a not guilty verdict.

  
  

• Challenged the Science Behind the Breathalyzer – Working with a former head of the Massachusetts State Crime Lab, Attorney Lown showed that officers failed to follow proper testing procedures and could not verify the machine's accuracy.

  
  

• Used the Officers’ Own Training Against Them – By obtaining police training records, Attorney Lown demonstrated that his client's driving and performance on field sobriety exercises were inconsistent with the officers' claims, helping persuade the jury to acquit.

Attorney Lown won a not guilty verdict at a DUI trial where police officers claimed that his client blew twice the legal limit on a breathalyzer and “failed” field sobriety exercises.

Prior to trial Lown hired a consultant, a former head of the Massachusetts State Crime Lab. This expert instructed Attorney Lown on the scientific principles that underlay the breathalyzer machine. Attorney Lown used this information to cross-examine the officers at trial. Through cross-examination, he showed that the officers did not follow testing protocols and did not know how to ensure the machine’s accuracy.

Attorney Lown also pulled the officers’ own training materials to prove that his client drove just fine that night and performed well on field sobriety exercises. These training materials described the impact of alcohol on a person's driving and balance. Through cross examination, Attorney Lown contrasted the official police description of a supposedly drunk person with his client who exhibited none of these signs. Attorney Lown also showed that a person who was supposedly twice the legal limit could have never performed so well.

Overall, Attorney Lown undermined every aspect of the prosecution’s case. The jurors returned a verdict of not guilty.

How do I challenge evidence of a failed breathalyzer, a blood alcohol reading of .08 (the legal limit) or higher?

• Was the officer qualified to administer the breathalyzer machine? Attorneys should determine whether the officer understood the breathalyzer’s internal functions and what it must do to produce an accurate result beyond merely asking a person to blow into a tube. 

• Was the person observed for at least 15 minutes before the test? Officers are required to monitor the person before testing because burping, hiccups, or acid reflux can introduce alcohol into the mouth and potentially increase the reading. If any of these occur, the officer must restart the 15-minute observation period.

• Was the testing device functioning properly? Review whether the machine was properly maintained, inspected, and certified for accuracy at the time of the test. Attorneys should note that annual laboratory testing provides the most comprehensive assessment of a machine's accuracy, while routine station-based checks are more limited and do not evaluate all of the device’s functions.

• Who performed the annual lab-based certification? If the chemist who certified the machine’s accuracy does not testify at trial, attorneys should be prepared to cross-examine the testifying police officer on how he or she is able to confirm that the correct testing procedures were done using the correct tools and chemicals in the correct order and whether the results were then correctly recorded in the absent chemist’s documentation. 

• Was the test administered correctly? Examine whether officers followed the required procedures and handled the equipment properly during testing. If there is booking video, attorneys should carefully watch how and where the testing was done, whether the machine started beeping, how long it took to produce a reading and whether the officers appeared to handle it confidently or with hesitation.

• The defense should consider seeking funds for a forensic chemist: Even if defense counsel is privately retained, the defendant may be entitled to court-authorized funds to hire an expert. Many defendants get help from family members to hire a private attorney. Defense counsel may ask the judge to focus on the defendant’s own income when deciding whether to authorize funds. The purpose of this rule is to ensure that no defendant faces an unfair disadvantage as compared to someone who can pay for the expert themselves. A forensic chemist can be invaluable for the defense, and can also testify at trial if necessary.

How do I challenge evidence that the person was “impaired,” “intoxicated” or "drunk driving"?

• It is not illegal to drink a beer at dinner and then drive home. It is not illegal to drink two beers. It is only illegal if the person drank to the level of impairment, meaning that they reduced their ability to safely drive.

• When challenging the prosecution’s evidence, one may consider whether the officer was merely looking to check boxes for impairment while ignoring everything that the person did right.

• For example, the person may have provided their license and registration when asked, exited their car without difficulty, answered questions appropriately, and among other things done correctly. All of this may be evidence that the person was not in fact impaired.

Frequently Asked Questions About DUI Cases Involving Failed Breathalyzer Tests

Can I beat a DUI charge if I failed a breathalyzer test?

Yes. A failed breathalyzer test does not automatically mean you will be convicted of DUI or OUI. An experienced defense attorney can challenge whether the breath test was administered correctly, whether the machine was functioning properly, and whether the police followed required testing procedures. In some cases, a breathalyzer reading can be excluded or its reliability undermined at trial.

What should I do if my breathalyzer result was over .08?

If your blood alcohol concentration (BAC) was .08 or higher, you should speak with a DUI lawyer as soon as possible. A BAC reading over the legal limit is important evidence for the prosecution, but it is not always conclusive. A skilled DUI attorney can investigate the circumstances surrounding the test and identify potential defenses.

Are breathalyzer tests always accurate?

No. Breathalyzer machines are sophisticated scientific instruments that require proper maintenance, calibration, certification, and operation. Even small errors can affect the accuracy of a breath test result. A DUI defense lawyer should review maintenance records, certification documents, and testing procedures to determine whether the result can be challenged.

Can a forensic chemist help defend a DUI case?

Yes. A forensic chemist can explain how breathalyzer machines work, identify scientific weaknesses in the testing process, and evaluate whether proper procedures were followed. In some cases, a forensic chemist can testify at trial and help a jury understand why a breath test result may be unreliable.

Can medical conditions affect a breathalyzer reading?

Yes. Conditions such as acid reflux, GERD, heartburn, and other digestive issues can sometimes introduce alcohol from the stomach into the mouth, potentially increasing a breathalyzer reading. Burping, hiccups, or regurgitation before testing may also affect the result if proper observation procedures were not followed.

Why is the 15-minute observation period important?

Before administering a breathalyzer test, officers are required to observe a person for at least 15 minutes. During this period, the officer must ensure that the person does not burp, hiccup, vomit, eat, drink, or place anything in their mouth. If any of these events occur, the observation period must restart. Failure to follow this protocol may provide grounds to exclude the breath test results prior to trial, or it may raise questions about the reliability of the breath test at trial.

Can a DUI attorney challenge the officer who administered the breathalyzer?

Yes. In some DUI trials, a key issue is whether the officer is simply “pressing buttons” or is actually competent to ensure the machine is producing a scientifically valid result. If the officer cannot explain what the machine is doing internally or how errors are prevented, that can weaken the reliability of the reading.

Can field sobriety tests help defend against a DUI charge?

Yes. In many DUI cases, field sobriety tests may contradict the prosecution's theory of intoxication. If a person performs well on balance, coordination, and divided-attention exercises, that evidence may be inconsistent with a claim that the person was significantly impaired or had a BAC far above the legal limit.

What evidence should a DUI defense lawyer review in a breath test case?

A thorough DUI defense investigation should include:

• Breathalyzer maintenance and certification records.

• Police reports and all police-generated documents.

• Booking room footage.

• Body camera and cruiser camera footage.

• Field sobriety test performance.

• Training materials used by the police department.

• The officer's certification and training history.

• Any medical conditions that may have affected the breath test.

Is it worth hiring a DUI lawyer if I failed both field sobriety tests and a breathalyzer?

Yes. Many people assume that a failed breath test or poor performance on field sobriety tests means there is no defense. In reality, DUI cases often involve complex scientific and procedural issues. An experienced criminal defense attorney can evaluate whether the evidence is reliable, whether constitutional rights were violated, and whether the prosecution can prove guilt beyond a reasonable doubt.

How can a DUI defense attorney win a case involving a breathalyzer result over the legal limit?

A successful DUI defense may involve challenging the breathalyzer's accuracy, exposing flaws in police procedures, demonstrating inconsistencies in the officer's testimony, presenting expert testimony, and showing that the defendant's driving, behavior, or field sobriety test performance was inconsistent with the prosecution's claims. Every case is different, and a thorough investigation is essential.