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What Evidence is Needed for a DUI Conviction?

What Evidence Is Needed for a Successful DUI Conviction?

In 2022, some 16,180 people were arrested for driving a vehicle under the influence of alcohol with a blood alcohol content over the legal limit in Colorado. However, there is a difference between a DUI charge and a DUI conviction. If you or your loved one are facing DUI charges but have not yet been convicted, it is important that you understand these differences and what evidence will be used against you in your DUI case. 

Driving under the influence (DUI) refers to operating a motor vehicle under the influence, either by alcohol or other drugs. DWAI, or “driving while ability impaired,” is a similar charge. Whichever you are charged with, the impact of your arrest may be far-reaching, including affecting your employment or other areas of your life. That’s why you need a good criminal defense attorney by your side.

The Denver defense attorneys at Wolf Law have managed hundreds of DUI cases, and we want to help you and your loved ones too. Gathering evidence to help your case is only part of our job – we also negotiate penalties and defend your rights. When you face a DUI conviction, learning a few key pieces of information about Colorado DUI laws can help ease your mind.

Evidence Initially Gathered When You Are Stopped by the Police

Colorado state laws prohibit driving, or being in actual physical control of a vehicle while under the influence of drugs or alcohol. This law applies to anyone sitting in the driver’s seat of a vehicle with the car keys in the vehicle’s ignition, hands on the steering wheel, or the car’s motor running. It also, of course, applies to actual driving taking place on a public roadway while under the influence of alcohol – AKA “drunk driving.”

Understanding Colorado DUI laws is key when you are pulled over or stopped by a law enforcement officer. Whether to take a breath or blood test, what a chemical test refusal may mean, and whether DUI charges are the same as a conviction, may all be concerns on your mind while sitting in the driver’s seat.

Law enforcement officers in Colorado are trained to observe certain driving behaviors that may indicate that the driver of the vehicle could be under the influence of drugs or alcohol. 

Some of these behaviors include:

  • Swerving or weaving while driving
  • Driving in between or across multiple lanes
  • Driving excessively fast or slow
  • Failing to turn on headlights at night
  • Failing to signal before a lane change
  • Responding slowly to change in traffic lights
  • Failing to stop at a stop sign
  • Tailgating

Once you have been pulled over, the police officer will likely ask whether you have been drinking or taking drugs. But, remember, you do not have to incriminate yourself and answer these questions. 

They may also ask you to participate in field sobriety tests (often referred to as “roadsides” or “PBT – preliminary breath tests, the handheld version). These tests are voluntary and you do not have to consent to field sobriety tests. 

The law is in place to protect your rights. Evidence gathered by the police in the form of your verbal admission of driving under the influence, video evidence, or the actions witnessed by the arresting officer in the field sobriety test, can be used as probable cause against you when facing a DUI conviction.

Key Evidence in DUI Convictions

Even though you have the right to refuse the field sobriety tests, due to Colorado’s Express Consent Law, you do not have the right to refuse a chemical test of Blood Alcohol Concentration (BAC) if the police officers have established probable cause that you were in physical control of a vehicle while past the legal limit. The BAC test may be either using your breath or blood. If you refuse to cooperate with this test, you will immediately get your license suspended and most likely be charged with a DUI.

The results of your BAC are a key piece of evidence in your DUI case. Breath test results are quick, so the officers will know almost immediately the percentage of your blood-alcohol content. If it is over .08, you will likely be charged with a DUI right there and then. By contrast, a BAC between .05 and .08 means you may be charged with DWAI.

If you take a blood test, the results take much longer to come in – even months in some cases. However, the result will most likely be very similar to the breath test. Remember that you do not have the right to speak to an attorney before giving these chemical tests. These test results can be the key piece of evidence for the prosecution in per se DUI convictions.

Timeline of DUI Cases

After being charged with driving under the influence or driving while ability impaired, there are two different proceedings. One has to do with your driving privileges, and this is overseen by the Colorado Division of Motor Vehicles, or DMV, acting as the arm of the Colorado Department of Revenue. The other is the criminal proceedings in the courthouse. 


The entity that determines whether or not your driving privileges will be revoked is the Colorado DMV. In some cases, your license is confiscated at the scene of your DUI arrest. However, license penalties vary based on several factors, such as your BAC, repeat offenses, and whether you consent or refuse chemical testing. 

You have 7 days to request a hearing with the DMV. This hearing is crucial to understanding your license restrictions in the face of a DUI arrest. License suspension for a first DUI charge in Colorado is usually 9 months, but may be shortened if an interlock device is installed and all requirements are met. 

Contacting a lawyer prior to the DMV hearing is advisable. 

The Courts

When you are arrested on a DUI charge, you receive a summons for a court date, typically within 30 to 60 days. That is what starts the judicial process of your case. Between the arrest and the court date, the charge will be submitted to the local prosecutor’s office. You will finally be expected to attend on your court date to plead innocent or guilty. 

During judicial proceedings, the evidence gathered by the police and the prosecutor will be presented. The prosecution will attempt to prove that you are guilty beyond a reasonable doubt. The court may impose fines, jail time, treatment programs, restitution, or probation if you are found guilty. Exactly what the penalties might be in your case depends on the circumstances surrounding your arrest and the judge or jury presiding over your case. 

The court process is separate from the DMV proceedings, and each has a different timeline. One does not necessarily affect the other. A lawyer can help rebut the prosecutor’s case, showing that there isn’t enough DUI evidence to prove your case beyond a reasonable doubt, pointing out circumstantial evidence, and presenting other evidence that can help lessen your chances of being convicted of a DUI.

Evidence the Prosecution Will Attempt to Use Against You

During a trial the prosecution proves, or attempts to prove a DUI charge against the defendant. However, just because a defendant is charged with DUI doesn’t necessarily mean he or she will be convicted of a DUI. The prosecution must prove that the defendant drove while under the influence of drugs or alcohol, using expert witnesses, law enforcement personnel, or other witnesses to the actual driving. 

The evidence used to prove drunk driving may include the driver’s BAC, other test results, as well as whether the defendant performed poorly in field tests. The judge or jury will require proof, backed up with enough evidence, to prove driving under the influence beyond a reasonable suspicion. The prosecution must prove that the defendant was in control of a vehicle on a public roadway while drunk or high. 

The jury deciding on a verdict of driving a vehicle under the influence against the defendant depends much on the prosecution and what they manage to prove. BAC tests are important for the prosecution to be able to prove your case. In Colorado, the per se DUI laws require the jury to convict someone with a blood alcohol level at or above .08. 

How a Lawyer Can Help

Having a qualified DUI defense attorney by your side can make a significant difference in the outcome of your drunk driving case. An experienced lawyer who knows Colorado DUI laws can help you understand the charges against you, explain what the prosecution will try to prove, and fight for the best possible result. 

Lawyers can do the following to defend your rights are:

  • Gather evidence, such as the reports, tests results, statements, and other relevant evidence collected in your case
  • Challenge the reliability of your BAC test results
  • Prove reasonable doubt in the case of the prosecution
  • Advocating for reduction of penalties
  • Negotiate a plea bargain with jail alternatives

If you are facing DUI charges and you want to lessen your chances of conviction or serious penalties, it’s wise to consult a DUI lawyer. If you are arrested for a DUI in Colorado, you need excellent and compassionate representation from a skilled DUI attorney familiar with the latest DUI laws. Contact us or call 720-479-8574 to schedule a free consultation to discuss your options.