Being charged with a DUI — short for Driving Under the Influence — can feel overwhelming. You may be unsure of what comes next, worried about your driving privileges, your job, or your reputation. The good news is that a DUI charge is not an automatic conviction. There are well-established legal defenses that a skilled attorney may be able to raise on your behalf depending on the facts of your case. Understanding those defenses is a helpful first step in knowing what your options may look like.
If you or someone you love is facing a DUI charge in Colorado, don't wait to take action — call us at (970) 352-8611 or reach out through our online contact form today.
Why DUI Defenses Matter
A DUI conviction in Colorado can carry serious consequences, including fines, license suspension, mandatory alcohol education programs, and even jail time. For repeat offenses, those consequences can be more severe. Because the stakes are high, it is important to understand that prosecutors must prove their case beyond a reasonable doubt. That is a high legal standard, and a thoughtful DUI defense strategy can challenge the evidence in ways that may lead to reduced charges, dismissed evidence, or even a case dismissal.
No two DUI cases are exactly alike. The strength of any defense depends on the specific facts — where and how you were stopped, what tests were administered, and how law enforcement handled the arrest. That is why speaking with a Greeley criminal defense attorney as early as possible after a DUI arrest is so important.
Defense #1: Lack of Probable Cause for the Traffic Stop
One of the most foundational protections in the American legal system is the Fourth Amendment, which guards against unreasonable searches and seizures. In practical terms, this means a police officer must have a valid legal reason — known as probable cause or reasonable suspicion — to pull you over in the first place.
If an officer stopped your vehicle without a legitimate reason, any evidence gathered during that stop may be challenged in court. This is sometimes called the "fruit of the poisonous tree" doctrine, which means that evidence obtained through an unlawful stop can potentially be excluded from your case. Without that evidence, the prosecution's case may fall apart entirely.
Common examples of questionable traffic stops include being pulled over for vague reasons, stops based on anonymous tips that lacked corroboration, or pretextual stops where the stated reason does not hold up. Your attorney can review the officer's report and dashcam footage to evaluate whether your stop was legally justified.
Defense #2: Challenging the Field Sobriety Tests
When an officer suspects a driver may be impaired, they often ask that driver to perform a series of roadside tests called standardized field sobriety tests (SFSTs). These typically include walking in a straight line, standing on one leg, and following a moving object with your eyes. Officers use these tests to build a case for impairment.
However, field sobriety tests are far from perfect. A number of factors unrelated to alcohol or drug use can affect how someone performs on these tests, including:
- Physical conditions such as inner ear problems, leg or back injuries, or neurological conditions
- Environmental factors like poor lighting, uneven road surfaces, or bad weather
- Anxiety or nervousness during the stop, which is a normal reaction
- Improper administration of the tests by the officer
After walking through that list, it becomes clear why these tests can be unreliable. An experienced DUI defense attorney will closely examine whether the tests were properly administered and scored according to established guidelines, and whether your performance could be explained by factors other than impairment.
Defense #3: Challenging the Breathalyzer Results
A breathalyzer is a device used to estimate a person's blood alcohol concentration (BAC) — the amount of alcohol in their bloodstream — by analyzing a breath sample. In Colorado, a BAC of 0.08% or higher is the legal limit for most drivers. A reading at or above that threshold is often a key piece of evidence in a DUI case.
But breathalyzer results are not infallible. There are several reasons why a reading may be inaccurate or misleading. Colorado law requires that breathalyzer devices be regularly calibrated and maintained, and that officers follow specific procedures when administering the test. If those requirements were not met, the results could be challenged.
Certain medical conditions — such as acid reflux or GERD (gastroesophageal reflux disease) — can cause mouth alcohol to contaminate the breath sample and inflate the reading. Similarly, diets low in carbohydrates (like ketogenic diets) can produce acetone in the breath that some breathalyzers may misread as alcohol. A Greeley criminal defense attorney can work with experts to scrutinize the device's maintenance records and the conditions under which the test was given.
Defense #4: Challenging Blood Test Results
In some DUI cases — particularly those involving suspected drug impairment or accidents — a blood test may be used instead of or in addition to a breathalyzer. Blood tests are generally considered more accurate than breath tests, but they still carry the potential for error.
The integrity of a blood sample depends heavily on how it was collected, stored, and analyzed. Improper handling can lead to contamination or fermentation, which can cause BAC readings to appear higher than they actually were at the time of the stop. There are also strict chain-of-custody requirements — meaning there must be a documented record of who handled the sample at every step — that, if broken, can call the reliability of the results into question.
Your attorney may request all documentation related to your blood draw and lab analysis as part of building your DUI defense. This process often requires the help of forensic toxicology experts who can evaluate whether the sample was handled properly and whether the reported BAC is scientifically defensible.
Defense #5: Rising BAC Defense
The rising BAC defense is one that many people are not aware of, and it can be particularly relevant in cases where a driver was tested a significant amount of time after they were stopped. Alcohol continues to be absorbed into the bloodstream after a person stops drinking, which means BAC levels can actually rise for a period of time following alcohol consumption.
If a driver had drinks shortly before getting in the car, their BAC at the time they were driving may have been below the legal limit — even if by the time they were tested at the police station, it had risen above 0.08%. This is a scientifically recognized phenomenon, and if the facts of your case support this defense, it could significantly impact the outcome.
The rising BAC defense typically requires the support of a toxicology expert who can reconstruct the timeline of a person's drinking and model how their BAC was likely changing over time. This kind of detailed analysis is one reason why having a knowledgeable attorney in your corner matters from the very beginning of your case.
What to Do After a DUI Arrest in Colorado
Knowing the defenses above is a good starting point, but understanding what to do immediately after a DUI arrest is equally important. Here are some key steps to keep in mind:
- Do not resist arrest or argue with law enforcement at the scene
- Politely decline to answer questions beyond basic identifying information until you have spoken with an attorney
- Take note of everything you remember about the stop, the tests administered, and the officers involved
- Request a hearing with the Colorado Division of Motor Vehicles (DMV) within seven days of your arrest to contest the automatic license suspension
- Contact a Greeley criminal defense attorney as soon as possible to begin reviewing the details of your case
Taking these steps promptly can help protect your rights and preserve important evidence. Every day that passes after an arrest is a day your attorney could have been working on your defense.
Talk to a Greeley DUI Defense Attorney at Peek Goldstone
A DUI charge in Colorado carries real consequences, but it is not a situation you have to face without guidance. The legal defenses discussed in this article show that the evidence against you is not always as clear-cut as it may seem, and there are legitimate legal strategies that may be available depending on your circumstances.
At Peek Goldstone, our legal team is committed to taking the time to understand your situation and helping you navigate the road ahead with clarity. We know this is a stressful time, and we are here to answer your questions and stand by your side throughout the process.
To speak with a Greeley criminal defense attorney about your DUI case, call us at (970) 352-8611 or reach out through our online contact form. We also offer consultations en español.