When you’re pulled over for suspected drunk driving in Denver, one of the most intimidating parts of the process is being asked to take a breathalyzer test. Law enforcement often treats these results as solid proof of intoxication, but they are far from infallible. Breathalyzer readings can be challenged—and in some cases, thrown out entirely—if your defense attorney can prove that they are unreliable.
A Denver DUI lawyer with experience in contesting chemical test results knows exactly where to look for errors and how to use them to your advantage in court. Here’s how the right defense strategy can dismantle a breathalyzer case.
Understanding How Breathalyzers Work
A breathalyzer measures blood alcohol content (BAC) by analyzing a sample of your breath. Colorado law sets the legal BAC limit at 0.08% for drivers over 21, 0.04% for commercial drivers, and 0.02% for drivers under 21.
The device assumes that alcohol in your breath reflects the same concentration as in your blood. While this technology is widely used, it’s based on scientific assumptions that aren’t perfect. A small miscalibration, human error, or environmental factor can dramatically change the results—and those results can make the difference between a conviction and a dismissal.
Common Issues That Affect Breathalyzer Accuracy
A Denver DUI lawyer knows there are multiple points where the process can fail. Common causes of inaccurate readings include:
Improper Calibration
Breathalyzers must be regularly calibrated to ensure accuracy. If the device hasn’t been maintained according to Colorado Department of Public Health and Environment (CDPHE) standards, its results may be invalid.
Operator Error
Officers must follow strict procedures when administering a breath test. Any deviation—such as failing to observe you for the required waiting period—can lead to inaccurate readings.
Medical Conditions
Certain medical issues, such as acid reflux, diabetes, or even a recent use of mouthwash, can cause artificially high BAC readings.
Environmental Factors
Substances like paint fumes, cleaning products, or even certain foods can interfere with the sensor and produce misleading results.
Legal Grounds for Challenging Breathalyzer Evidence
A skilled Denver DUI lawyer will carefully review every aspect of your case to determine whether the breathalyzer evidence is admissible in court. Some common legal challenges include:
1. Questioning Device Maintenance Records
Your lawyer can request maintenance and calibration logs for the breathalyzer used in your arrest. If the records are incomplete or show irregularities, the results may be thrown out.
2. Reviewing Officer Training
Only certified operators can administer a breath test in Colorado. If the officer who conducted your test lacked proper training or certification, the results may be invalid.
3. Challenging the Observation Period
Colorado law generally requires officers to observe a suspect for a set period before administering the test to ensure they don’t eat, drink, smoke, or vomit. Skipping or shortening this period can compromise accuracy.
4. Highlighting Medical Interference
If you have a documented medical condition that could affect results, your attorney can present expert testimony to explain how the breathalyzer reading may not reflect actual impairment.
5. Contesting Chain of Custody
For more advanced devices or situations involving blood tests, the prosecution must prove an unbroken chain of custody for the evidence. Any gaps can lead to suppression of the results.
The Role of Expert Witnesses
Many successful DUI defenses rely on expert testimony. A Denver DUI lawyer may work with forensic toxicologists who can explain to the jury why a breathalyzer reading may be unreliable. These experts can dissect the science behind the device, point out its limitations, and raise reasonable doubt about the prosecution’s case.
Why Breathalyzer Results Aren’t the End of the Story
One of the most common misconceptions is that a failed breathalyzer test automatically means a conviction. In reality, DUI cases in Colorado hinge on whether the prosecution can prove impairment beyond a reasonable doubt.
Even if your BAC was over the legal limit according to the machine, that doesn’t mean the reading will hold up in court. A seasoned defense attorney can cast doubt on the accuracy of the test, making it harder for the prosecution to meet its burden of proof.
Real-World Example: Breathalyzer Suppressed
In one Denver case, a driver was arrested after blowing a BAC of 0.10%. The defense attorney discovered that the breathalyzer had not been calibrated in over a month, contrary to state requirements. Additionally, the officer failed to observe the driver for the full 20 minutes before the test. The judge ruled the results inadmissible, and the charges were reduced to a lesser offense.
Why You Need a Local Denver DUI Lawyer
Colorado DUI laws are complex, and every court in the Denver area has its own procedures. Hiring a Denver DUI lawyer who regularly appears in local courts gives you a strategic advantage. They understand how prosecutors handle breathalyzer evidence, know which judges are more receptive to technical challenges, and can anticipate the tactics used against you.
How Baker Law Group Can Help
At Baker Law Group, our DUI defense team takes a detailed, aggressive approach to challenging breathalyzer results. When you hire us, we will:
- Review every step of your arrest to identify procedural mistakes
- Examine maintenance and calibration logs for the testing device
- Consult with scientific experts to challenge the reliability of the results
- Negotiate with prosecutors to seek reduced charges or dismissal
- Fight for you in court if your case goes to trial
We understand the stress and uncertainty that come with a DUI charge. Our goal is to protect your rights, your license, and your future.
Take Action Today
If you’ve been arrested for DUI in Denver and failed a breathalyzer test, don’t assume your case is hopeless. Breathalyzer results can be challenged, and in many cases, successfully excluded from evidence.
Contact Baker Law Group today to speak with an experienced Denver DUI lawyer. We’ll review your case, explain your legal options, and build a defense strategy tailored to your situation.
