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Colorado Criminal Defense and Personal Injury Attorneys

Free Consultation : (303) 440-0123




Colorado DUI law requires that you consent to a sobriety test, typically blood or breath, if a police officer has reasonable grounds to believe that you were driving under the influence or driving while your ability was impaired (DWAI) because of the consumption of alcohol, drugs or both.

It is also important to note that in Colorado you can be charged as a DUI driver whether the drugs that were taken or suspected of being taken, were prescribed or were obtained over-the-counter, such as a cough medicine.

In circumstances where you are given a DUI test and the results indicate that you consumed no alcohol, an officer can request a second test of your blood, urine or saliva for drugs.

Absent medical issues, a pending felony charge, a specific focus on drug intoxication or impairment, or “extraordinary circumstances” which Colorado law defines as including weather related delays, high call volumes involving medical personnel, power outages, malfunctioning breath test equipment and other circumstances that preclude the timely collection of a breath or blood sample by a qualified person in accordance with law, you get to choose your DUI test. However, you don’t get to change your mind once you’ve notified the officer of your choice.

Important legal issues arise when an officer doesn’t honor your choice of a DUI test, if you refuse a DUI test, if you reconsider your earlier refusal to submit to a DUI test and the officer refuses your request, and when an officer or police agency fails to comply with the rules and regulations that govern DUI tests in Colorado.

In Colorado a DUI test result that registers between .02 and .05 blood alcohol content (BAC) for an individual under the age of 21, will result in a charge of underage DUI. A DUI test result between .05 and .079 BAC will result in a charge of DWAI, a DUI test result over.08 will result in a charge of DUI, with enhanced penalties for test results over .200 BAC.

Police officers will frequently charge a person with a DUI test over .08 BAC with both DUI and DUI per se, essentially this gives police and prosecutors two ways to convict you of DUI. A charge of DUI requires proof beyond a reasonable doubt that you were substantially incapable of safely driving as a result of the consumption of alcohol, drugs or both. To prove you were guilty of a DUI per se charge a prosecutor needs only to establish that you were driving with a BAC over .08 beyond a reasonable doubt.

You can be prosecuted for DUI in Colorado even when you refuse a chemical test and it is important to know that in Colorado a jury will be told, in most cases, that you refused to be tested.

Contact Mertes Law Today

The mertes law logo - Colorado DUI Law attorneysWhen your freedom and reputation are at stake, get the best representation. Speak to the Boulder criminal defense attorneys at Mertes Law for experienced help today, and get the representation you deserve. Schedule a free consultation today by filling out the contact form on this page, or by calling (303) 440-0123. 

“Larry Mertes is Exceptional”

– Katie S. –

Larry Mertes is exceptional. His legal advice, guidance, and compassion resulted in a positive legal outcome and our family healing. He is much more than a talented and educated attorney, he was a beacon of hope and a friend during our families darkest hour.

“Care, Compassion, and Professionalism”

– M. Rider –

The Mertes Law Firm handled my case with care, compassion, and the high level of professionalism. I would highly recommend Larry Mertes to anyone needing legal assistance.

“Great Representation”

– Sheryle M. –

I have had fair and great representation with this firm.

“Larry and his staff took excellent care of both my husband and I”

– Car Accident Client –

Larry and his staff took excellent care of both my husband and I. My injury was not severe but it changed both of our lives. I am not a fan of litigation so I tried to get better on my own. My treatments were costly and I continued to struggle. I had to give up many of the things that gave me pleasure. Larry made me realize that I still had rights even though I had a previous injury. I was not the same person. It was good to have Larry in my corner.

“Much needed help in my time of need!”

– Christa –

Larry Mertes and staff provided me with exceptional representation in my biggest time of need. After being rear-ended, I attempted to handle everything myself, which ended up feeling like a second job. I was in deep turmoil with paperwork, doctor bills, physical and mental pain, and confusion….and Larry Mertes and his team set up a free consultation immediately. They explained the whole process clearly, and eased my mind by handling the case. I’m extremely satisfied with their professionalism, time, dedication, and care that they showed me and my case. Someone I know recommended Larry to me and now I recommend him to you!

“I love Mertes Law”

– Nyxi –

I love Mertes Law. Not only is Larry Mertes a brilliant, thorough, experienced, knowledgeable, and well networked lawyer, he is a kind, intuitive, caring, trustworthy, and genuine person. What seemed like an unfortunate circumstance actually ended up a blessing in disguise, and meeting and hiring Mertes Law was the catalyst. I now have a greater understanding of the insurance business so I can make sure I’m taken care of. The health care professionals Larry put me in contact with matched my personal needs and I’ve retained lasting, cherished relationships, both professionally and personally. Thank you!

“A great choice in an attorney for us.”

– Anonymous –

We hired Larry to help seal the files of felony charge for my husband that had occurred several years ago. There were a lot of crazy circumstance to the original case/charges that made it seem impossible. It was difficult to do for many reasons but Larry got it done.

“The entire staff was great!”

– John –

They handled a DWI and Criminal Mischief case for us. Very patient and helpful!! The entire staff was GREAT!!!

“Great services, and excellent result, well worth the time and money!”

– Jeremy –

Larry Mertes handled my DUI case in a very professional manner. I got positive feedback from the start, as he had a lot of questions I never would have thought of when we had our initial consultation. I understood that due to the large number of cases the firm handles, I had to be patient to hear a response back. But it was always a very thorough response, and he made good suggestions. TJ Willard also assisted in my case, and helped me to win my administrative hearing by simply stating the facts and explaining that I was only sitting in the vehicle, and not actually driving it. He had helped Larry a great deal with my case and I would also recommend his services. Larry had recommended a good course of action for me to take to help my case to include gathering as much information and evidence as I could and attending alcohol classes ahead of time for my DUI charge. All of this preparation had helped put me in a good situation. He had presented an excellent argument toward the District Attorney stating that I had not intended to drive, and was merely sitting in the car staying warm to try to figure out what to do next. He also mentioned the arresting officer had no reasonable suspicion for approaching my vehicle because I had tinted windows and he could not see inside. I was also parked legally in a parking garage. The DA had later reached a plea bargaining agreement, and I plead guilty to a reckless driving offense with community service, and my DUI charge had been dismissed. Well worth the cost and peace of mind of maintaining a clean criminal record. I would strongly recommend Larry Mertes for his legal services! Thank you!

“Reduced 4 felonies to deferred misdemeanor…”

– Rob –

Larry and TJ were very adept at handling both my son and the DA in dealing with my son’s felony charges. With some sage advice to take an extra two weeks on bond, my son was able to demonstrate he was trying to get back on track, and the bond officer was able to give an excellent report. TJ was right there helping my son see what he needed to do, and encourage him to keep trying to put his best foot forward with the judge, DA, and bond officer.


– Jack –

Mr. Mertes resolved my case in a expedient and professional manner. I had multiple serious charges and he was able to reduce my felony charges down to a 1st class misdemeanor. He was very compassionate and was always available to discuss my case. From arrest to disposition was only 36 days. He should be appointed to be a judge in my opinion.

“Mertes Law Office did an outstanding job…”

– Max H. –

The Mertes Law Office did an outstanding job in analyzing each piece of my case and strategizing ways to determine whether or not I was charged fairly. Throughout dealing with me their team stayed on top of everything, made sure I was informed and updated in addition they answered all of my questions promptly. In the end I was able to keep a clean record and received the best outcome due to their recommendations. Mertes Law will not disappoint.

“Exceptional law firm and had a great experience with them!”

– Abigail A. –

Exceptional law firm and had a great experience with them! 100% recommend 🙂

“Larry represented me a few times for cases involving auto accidents and he never ceased to impress.”

– Brycen –

Larry represented me a few times for cases involving auto accidents and he never ceased to impress. He understands the system and insurance companies very well and always painted a clear picture of what the plan was. His coaching for times when I had to speak, like depositions, was always on point. He referred me to great doctors who helped me get healthy and whose reports helped aid our case. Whenever Larry was wasn’t immediately available, the staff was always eager and willing to help. Beyond being great at what he does, Larry also took interest in my personal life by getting to know me and ensuring the legal process didn’t derail everything else in my life. He cared from day 1 and it has always been appreciated.

“Mertes Law Firm has helped our family in many ways!”

– Lori –

Mertes Law Firm has helped our family in many ways! They are smart, thorough and willing to step outside the box to find solutions. In times of much stress, they can be counted on to provide information in a format that is easy to understand. I cannot recommend them enough.

“I’m so happy and grateful I chose them to help me.”

– Sara –

I’ve recently used Mertes Law and cannot be happier with their service. Both Larry and Pete made me feel welcome and helped ease my worries about possible outcomes. They always kept me in the loop and made sure I understood all of my options before I made a decision. If it wasn’t for their professional guidance, I wouldn’t have had the outcome I received. I’m so happy and grateful I chose them to help me. I would never use anyone else and highly recommend them both.

“Larry and his staff have been great resources for my family and I.”

– Michael U. –

Larry and his staff have been great resources for my family and I. Providing excellent guidance in a timely and fashionable manner. Highly recommended.

“Larry Mertes is a dedicated and experienced attorney committed to putting the needs of his clients first.”

– Leb B. –

Larry Mertes is a dedicated and experienced attorney committed to putting the needs of his clients first.

“5 stars”

– Travis L. –

5 stars

“Super smart, great to work with, outstanding results!”

– Sara –

Larry and his team were beyond great! It was such a relief to hand my legal issues over to them so that I could focus on healing after my car accident. The folks at Mertes Law worked hard on my behalf and got a great settlement. I’m very grateful for everything they’ve done. Thanks, Larry, Karen, and Mariah!


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