Colorado police usually build a drug DUI case from a timeline of evidence rather than one decisive test. Officers may rely on driving behavior, roadside observations, statements, field sobriety exercises, a Drug Recognition Expert evaluation, body-camera or dash-camera video, physical evidence, and toxicology results.
A positive blood test can show that a drug or metabolite was detected. It does not automatically prove that you were impaired when you drove. Drug concentration, timing, tolerance, metabolism, medical conditions, fatigue, anxiety, injuries, lawful medication use, and laboratory procedures can all affect how the evidence should be interpreted.
Hebets & McCallin P.C. reviews each stage of the investigation, including the reason for the traffic stop, the officer’s observations, the roadside exercises, the arrest decision, the chemical test, and the laboratory records. The question is not whether one item sounds suspicious. The question is whether the complete evidence proves impairment beyond a reasonable doubt.
A drug test can show presence. It does not always show real-time impairment.
What Must Prosecutors Prove in a Colorado Drug DUI Case? 
Colorado does not create a separate criminal offense called DUID. Drug-related impaired-driving cases are prosecuted under the state’s DUI and DWAI laws.
- DUI: Prosecutors must prove that alcohol, one or more drugs, or a combination affected you to a degree that you were substantially incapable, mentally or physically, of exercising clear judgment, sufficient physical control, or due care in the safe operation of a vehicle.
- DWAI: Prosecutors must prove that alcohol, one or more drugs, or a combination affected you to the slightest degree so that you were less able to drive than you ordinarily would have been.
The term “drug” can include marijuana, controlled substances, prescription medication, and some over-the-counter products. Lawful possession or a valid prescription does not resolve the case. Prosecutors still must connect the substance to your ability to drive.
For more information about drug-related DUI charges, visit:
https://www.hebetsmccallin.com/denver-duid-lawyers/
Driving Behavior Before the Stop
A drug DUI investigation often begins before an officer approaches your vehicle. The police report may describe:
- Weaving or drifting within a lane
• Crossing a lane marker
• Delayed braking
• Stopping beyond a limit line
• An unusually wide or abrupt turn
• Inconsistent speed
• Slow responses to traffic signals
• Following another vehicle too closely
These observations may support a traffic stop, but they do not prove drug impairment by themselves. Road design, poor visibility, traffic, distraction, fatigue, vehicle problems, unfamiliar streets, or an attempt to avoid a hazard may explain the driving.
Video can be critical. Dash-camera footage, traffic-camera footage, nearby surveillance video, GPS information, vehicle data, and witness accounts may confirm or contradict the officer’s description.
The legal basis for the stop matters as well. If the officer lacked reasonable suspicion that a traffic violation or crime occurred, your attorney may examine whether evidence gathered after the stop can be suppressed.
For a seasonal example of how police organize this evidence around concerts, festivals, and other events, review:
https://www.hebetsmccallin.com/how-colorado-police-build-drug-dui-cases-summer-events/
Just like anything else, practice leads to proficiency. With over 35 years of combined experience, we've gathered extensive knowledge inside and outside the courtroom.
What the Officer Observes at the Vehicle
After the stop, an officer may document your appearance, speech, movements, attention, and ability to follow instructions. A report may mention:
- Red or watery eyes
• Unusual pupil size
• Slow responses
• Rapid or slurred speech
• Tremors
• Confusion
• Poor coordination
• Unusual muscle tone
• An odor associated with marijuana
Many of these observations have possible non-drug explanations. Allergies, contact lenses, lack of sleep, stress, pain, medical conditions, prescribed medication, bright lights, cold weather, and fear can affect how you look or act.
Body-camera video lets your attorney compare the written report with the actual encounter. A report may describe you as confused or unsteady, while the recording may show clear answers, ordinary movement, and consistent cooperation. The complete recording matters more than a few selected phrases.
Statements and Alleged Admissions
Officers may ask when you last used marijuana, whether you took medication, what dosage you took, where you were coming from, whether you feel impaired, and whether drugs are inside the vehicle.
Your answers can become central evidence. You may estimate the timing incorrectly, misunderstand a question, or provide incomplete information while anxious. Police may compare your statements with receipts, messages, prescription records, packaging, witness accounts, or video.
Your attorney may review:
- Whether you were in custody when questioning occurred
• Whether Miranda warnings were required
• Whether your statements were voluntary
• Whether language, hearing, medical, or cognitive issues affected the exchange
• Whether the report accurately quotes or summarizes your answers
• Whether the recording provides context that the report leaves out
Miranda warnings are not required for every roadside question. The timing, location, level of restraint, and nature of the questioning must be evaluated.
Excellent Attorney
Collin McCallin performed EXCELLENTLY with my case. He kept in consistent contact with me throughout and showed diligence and extreme care for what I was dealing with.
He worked effectively with the district attorney to resolve my case, and I could not be more pleased with the work. Thanks again!
- Tim W
The Best Choice
Working with Russell lifted a huge weight off of our shoulders and allowed my husband and me to get back to living our lives knowing we were in good hands. Russell is truly a genuine and caring person and my husband and I will forever be grateful for the hard work, empathy, and support Russell gave us with my case. His persistence and determination resulted in a full dismissal of all of the charges!"
- Anonymous
Field Sobriety Exercises
Police may ask you to perform roadside exercises such as the walk-and-turn, one-leg stand, or horizontal gaze nystagmus test. Officers may also use added observations when they suspect drugs rather than alcohol.
These exercises do not measure a specific quantity of a drug in your body. Performance may be affected by:
- Uneven pavement, gravel, snow, or a sloped shoulder
• Passing traffic, noise, or flashing lights
• Footwear or restrictive clothing
• Age, weight, injury, or balance problems
• Neurological or medical conditions
• Fatigue, anxiety, or pain
• Unclear instructions or an incomplete demonstration
Your attorney should compare the officer’s instructions, demonstration, scoring, and written conclusions with the video.
More information about roadside testing is available at:
https://www.hebetsmccallin.com/denver-field-sobriety-test-attorneys/
Drug Recognition Expert Evaluations
A Drug Recognition Expert, commonly called a DRE, is a law enforcement officer trained to conduct a structured drug-impairment evaluation. The National Highway Traffic Safety Administration describes a 12-step protocol used to assess whether a person appears impaired, whether a medical condition may explain the observations, and which drug category may be involved.
A DRE evaluation may include:
- An interview with the arresting officer
• A preliminary examination and pulse reading
• Eye examinations
• Divided-attention exercises
• Blood pressure, temperature, and pulse measurements
• Dark-room examinations
• Muscle-tone observations
• A check for possible injection sites
• Questions about medication or drug use
• A toxicological sample
A DRE opinion remains an officer’s interpretation. NHTSA reports that research concerning the ability of DREs to classify the responsible drug category has produced mixed results. Accuracy may depend on the officer’s experience, the drug category, and whether more than one substance is involved.
A defense review may examine:
- Training and certification records
• Whether all required steps were completed
• Whether measurements were taken and recorded correctly
• Whether the officer considered medical explanations
• Whether the predicted drug category matched the toxicology result
• Whether the report and video are consistent
• Whether the evaluation occurred under suitable conditions
Learn more about these evaluations at:
https://www.hebetsmccallin.com/denver-drug-recognition-attorneys/
Blood, Urine, Saliva, and Toxicology Evidence
Drug DUI cases often involve a blood sample because breath testing generally measures alcohol rather than most drugs. Depending on the circumstances, a laboratory may test for active THC, THC metabolites, prescription medications, stimulants, opioids, sedatives, or other substances.
A toxicology report may establish that a substance or metabolite was detected. It may not establish when the substance was used, how much was used, or whether the measured concentration caused impairment. Interpretation depends on the substance, dose, timing, tolerance, metabolism, drug interactions, and laboratory limits.
Colorado law provides that five nanograms or more of delta-9 THC per milliliter of whole blood, at the time of the alleged offense or within a reasonable time afterward, creates a permissible inference that the driver was under the influence of one or more drugs. This is not an automatic conviction. You may present evidence challenging whether you were impaired.
Laboratory evidence should be reviewed for:
- Who collected the sample and whether that person was qualified
• Whether the collection process complied with applicable rules
• Whether the correct tubes and preservatives were used
• Labeling, sealing, storage, transport, and chain of custody
• Testing methods, calibration, quality controls, and measurement uncertainty
• Whether contamination, degradation, or a sample mix-up is possible
• Whether the result identified an active drug or only a metabolite
• Whether a preserved sample can be independently retested
Colorado requires qualifying forensic toxicology laboratories to meet certification or accreditation requirements and proficiency-testing standards. Those safeguards do not make every result unquestionable. The records still require case-specific review.
Physical Evidence, Witnesses, and Digital Records
Police may photograph or seize medication containers, cannabis products, suspected drugs, paraphernalia, receipts, or other items found in a vehicle. Possession may support an investigation, but possession alone does not prove recent use or impaired driving.
Other evidence may include:
- Passenger or witness statements
• 911 calls and dispatch communications
• Body-camera and dash-camera footage
• Parking-lot or business surveillance footage
• Phone data obtained through lawful process
• Vehicle event data
• Medical and prescription records
• Photographs, measurements, and damage patterns in a crash case
• Statements made to paramedics or medical personnel
Your attorney should examine whether a search was lawful, whether an item belonged to you, whether the evidence was properly preserved, and whether the claimed timeline is consistent.
Can Police Build a Case Without a Positive Blood Test?
Yes. Prosecutors may rely on driving observations, officer testimony, video, statements, roadside exercises, a DRE opinion, witness testimony, physical evidence, or an alleged refusal.
Colorado’s express consent law authorizes a requested blood, breath, saliva, or urine test when an officer has probable cause to believe that a driver committed DUI or DWAI. A refusal may be admitted in court and may support driver’s license consequences.
A refusal does not prove impairment by itself. Your attorney may review:
- The wording and timing of the advisement
• Whether the officer made a clear request
• Your response and whether it was accurately recorded
• Medical limitations that affected your ability to complete a test
• Confusion, language barriers, or hearing issues
• Whether police later obtained a warrant
• Whether the collection process complied with the warrant
How a Colorado Drug DUI Lawyer Reviews the Evidence
A careful defense review asks whether the pieces fit together or only appear persuasive when viewed separately. Your attorney may:
- Compare police reports with every available recording
• Obtain dispatch records and laboratory documents
• Review the DRE report and the officer’s training history
• Inspect or photograph the stop location
• Interview passengers and other witnesses
• Review medical history and prescription information
• Consult a toxicologist when the scientific issues require it
• Examine the legality of the stop, arrest, search, and chemical test
• Determine whether prosecutors can prove impairment rather than drug presence alone
The strongest review follows the entire timeline, from the first claimed driving error through the final laboratory report.
The firm’s DUI frequently asked questions are available at:
https://www.hebetsmccallin.com/frequently-asked-questions-about-duis/
What You Can Preserve After a Drug DUI Arrest
Evidence can disappear quickly. Keep the paperwork provided by police, the court, the jail, the hospital, and the Colorado Division of Motor Vehicles.
You should also preserve:
- Event tickets, receipts, and parking records
• Messages and location data that help establish timing
• Photographs of the roadway, shoulder, weather, or lighting
• Prescription labels and pharmacy records
• Medical information related to balance, vision, speech, or coordination
• Names and contact information for passengers or witnesses
• Clothing and footwear worn during roadside exercises
• Notes describing what you remember about the stop and testing
Do not alter records or post details about the case on social media. Speak with an attorney before providing additional statements about the allegation.
Speak With a Colorado Drug DUI Defense Attorney
A drug DUI allegation may involve police judgment, scientific testing, constitutional questions, and separate court and driver’s license deadlines. Hebets & McCallin P.C. represents people facing DUI and DWAI allegations in Denver, Colorado, and nearby areas.
The firm’s attorneys are former prosecutors with experience reviewing traffic stops, body-camera footage, roadside exercises, DRE evaluations, blood draws, toxicology records, searches, and possible defenses. Every case depends on its own facts, and no particular result can be promised.
Call 303-854-6006 for a free consultation, or visit:
https://www.hebetsmccallin.com/contact-us/
This article is for general informational purposes only and is not legal advice. Every case is different. Consult an attorney about your specific circumstances.
Colorado police usually build a drug DUI case from a timeline of evidence rather than one decisive test. Officers may rely on driving behavior, roadside observations, statements, field sobriety exercises, a Drug Recognition Expert evaluation, body-camera or dash-camera video, physical evidence, and toxicology results.
A positive blood test can show that a drug or metabolite was detected. It does not automatically prove that you were impaired when you drove. Drug concentration, timing, tolerance, metabolism, medical conditions, fatigue, anxiety, injuries, lawful medication use, and laboratory procedures can all affect how the evidence should be interpreted.
Hebets & McCallin P.C. reviews each stage of the investigation, including the reason for the traffic stop, the officer’s observations, the roadside exercises, the arrest decision, the chemical test, and the laboratory records. The question is not whether one item sounds suspicious. The question is whether the complete evidence proves impairment beyond a reasonable doubt.
A drug test can show presence. It does not always show real-time impairment.
What Must Prosecutors Prove in a Colorado Drug DUI Case?
Colorado does not create a separate criminal offense called DUID. Drug-related impaired-driving cases are prosecuted under the state’s DUI and DWAI laws.
- DUI: Prosecutors must prove that alcohol, one or more drugs, or a combination affected you to a degree that you were substantially incapable, mentally or physically, of exercising clear judgment, sufficient physical control, or due care in the safe operation of a vehicle.
- DWAI: Prosecutors must prove that alcohol, one or more drugs, or a combination affected you to the slightest degree so that you were less able to drive than you ordinarily would have been.
The term “drug” can include marijuana, controlled substances, prescription medication, and some over-the-counter products. Lawful possession or a valid prescription does not resolve the case. Prosecutors still must connect the substance to your ability to drive.
For more information about drug-related DUI charges, visit:
https://www.hebetsmccallin.com/denver-duid-lawyers/
Driving Behavior Before the Stop
A drug DUI investigation often begins before an officer approaches your vehicle. The police report may describe:
- Weaving or drifting within a lane
• Crossing a lane marker
• Delayed braking
• Stopping beyond a limit line
• An unusually wide or abrupt turn
• Inconsistent speed
• Slow responses to traffic signals
• Following another vehicle too closely
These observations may support a traffic stop, but they do not prove drug impairment by themselves. Road design, poor visibility, traffic, distraction, fatigue, vehicle problems, unfamiliar streets, or an attempt to avoid a hazard may explain the driving.
Video can be critical. Dash-camera footage, traffic-camera footage, nearby surveillance video, GPS information, vehicle data, and witness accounts may confirm or contradict the officer’s description.
The legal basis for the stop matters as well. If the officer lacked reasonable suspicion that a traffic violation or crime occurred, your attorney may examine whether evidence gathered after the stop can be suppressed.
For a seasonal example of how police organize this evidence around concerts, festivals, and other events, review:
https://www.hebetsmccallin.com/how-colorado-police-build-drug-dui-cases-summer-events/
Just like anything else, practice leads to proficiency. With over 35 years of combined experience, we've gathered extensive knowledge inside and outside the courtroom.
What the Officer Observes at the Vehicle
After the stop, an officer may document your appearance, speech, movements, attention, and ability to follow instructions. A report may mention:
- Red or watery eyes
• Unusual pupil size
• Slow responses
• Rapid or slurred speech
• Tremors
• Confusion
• Poor coordination
• Unusual muscle tone
• An odor associated with marijuana
Many of these observations have possible non-drug explanations. Allergies, contact lenses, lack of sleep, stress, pain, medical conditions, prescribed medication, bright lights, cold weather, and fear can affect how you look or act.
Body-camera video lets your attorney compare the written report with the actual encounter. A report may describe you as confused or unsteady, while the recording may show clear answers, ordinary movement, and consistent cooperation. The complete recording matters more than a few selected phrases.
Statements and Alleged Admissions
Officers may ask when you last used marijuana, whether you took medication, what dosage you took, where you were coming from, whether you feel impaired, and whether drugs are inside the vehicle.
Your answers can become central evidence. You may estimate the timing incorrectly, misunderstand a question, or provide incomplete information while anxious. Police may compare your statements with receipts, messages, prescription records, packaging, witness accounts, or video.
Your attorney may review:
- Whether you were in custody when questioning occurred
• Whether Miranda warnings were required
• Whether your statements were voluntary
• Whether language, hearing, medical, or cognitive issues affected the exchange
• Whether the report accurately quotes or summarizes your answers
• Whether the recording provides context that the report leaves out
Miranda warnings are not required for every roadside question. The timing, location, level of restraint, and nature of the questioning must be evaluated.
Excellent Attorney
Collin McCallin performed EXCELLENTLY with my case. He kept in consistent contact with me throughout and showed diligence and extreme care for what I was dealing with.
He worked effectively with the district attorney to resolve my case, and I could not be more pleased with the work. Thanks again!
- Tim W
The Best Choice
Working with Russell lifted a huge weight off of our shoulders and allowed my husband and me to get back to living our lives knowing we were in good hands. Russell is truly a genuine and caring person and my husband and I will forever be grateful for the hard work, empathy, and support Russell gave us with my case. His persistence and determination resulted in a full dismissal of all of the charges!"
- Anonymous
Field Sobriety Exercises
Police may ask you to perform roadside exercises such as the walk-and-turn, one-leg stand, or horizontal gaze nystagmus test. Officers may also use added observations when they suspect drugs rather than alcohol.
These exercises do not measure a specific quantity of a drug in your body. Performance may be affected by:
- Uneven pavement, gravel, snow, or a sloped shoulder
• Passing traffic, noise, or flashing lights
• Footwear or restrictive clothing
• Age, weight, injury, or balance problems
• Neurological or medical conditions
• Fatigue, anxiety, or pain
• Unclear instructions or an incomplete demonstration
Your attorney should compare the officer’s instructions, demonstration, scoring, and written conclusions with the video.
More information about roadside testing is available at:
https://www.hebetsmccallin.com/denver-field-sobriety-test-attorneys/
Drug Recognition Expert Evaluations
A Drug Recognition Expert, commonly called a DRE, is a law enforcement officer trained to conduct a structured drug-impairment evaluation. The National Highway Traffic Safety Administration describes a 12-step protocol used to assess whether a person appears impaired, whether a medical condition may explain the observations, and which drug category may be involved.
A DRE evaluation may include:
- An interview with the arresting officer
• A preliminary examination and pulse reading
• Eye examinations
• Divided-attention exercises
• Blood pressure, temperature, and pulse measurements
• Dark-room examinations
• Muscle-tone observations
• A check for possible injection sites
• Questions about medication or drug use
• A toxicological sample
A DRE opinion remains an officer’s interpretation. NHTSA reports that research concerning the ability of DREs to classify the responsible drug category has produced mixed results. Accuracy may depend on the officer’s experience, the drug category, and whether more than one substance is involved.
A defense review may examine:
- Training and certification records
• Whether all required steps were completed
• Whether measurements were taken and recorded correctly
• Whether the officer considered medical explanations
• Whether the predicted drug category matched the toxicology result
• Whether the report and video are consistent
• Whether the evaluation occurred under suitable conditions
Learn more about these evaluations at:
https://www.hebetsmccallin.com/denver-drug-recognition-attorneys/
Blood, Urine, Saliva, and Toxicology Evidence
Drug DUI cases often involve a blood sample because breath testing generally measures alcohol rather than most drugs. Depending on the circumstances, a laboratory may test for active THC, THC metabolites, prescription medications, stimulants, opioids, sedatives, or other substances.
A toxicology report may establish that a substance or metabolite was detected. It may not establish when the substance was used, how much was used, or whether the measured concentration caused impairment. Interpretation depends on the substance, dose, timing, tolerance, metabolism, drug interactions, and laboratory limits.
Colorado law provides that five nanograms or more of delta-9 THC per milliliter of whole blood, at the time of the alleged offense or within a reasonable time afterward, creates a permissible inference that the driver was under the influence of one or more drugs. This is not an automatic conviction. You may present evidence challenging whether you were impaired.
Laboratory evidence should be reviewed for:
- Who collected the sample and whether that person was qualified
• Whether the collection process complied with applicable rules
• Whether the correct tubes and preservatives were used
• Labeling, sealing, storage, transport, and chain of custody
• Testing methods, calibration, quality controls, and measurement uncertainty
• Whether contamination, degradation, or a sample mix-up is possible
• Whether the result identified an active drug or only a metabolite
• Whether a preserved sample can be independently retested
Colorado requires qualifying forensic toxicology laboratories to meet certification or accreditation requirements and proficiency-testing standards. Those safeguards do not make every result unquestionable. The records still require case-specific review.
Physical Evidence, Witnesses, and Digital Records
Police may photograph or seize medication containers, cannabis products, suspected drugs, paraphernalia, receipts, or other items found in a vehicle. Possession may support an investigation, but possession alone does not prove recent use or impaired driving.
Other evidence may include:
- Passenger or witness statements
• 911 calls and dispatch communications
• Body-camera and dash-camera footage
• Parking-lot or business surveillance footage
• Phone data obtained through lawful process
• Vehicle event data
• Medical and prescription records
• Photographs, measurements, and damage patterns in a crash case
• Statements made to paramedics or medical personnel
Your attorney should examine whether a search was lawful, whether an item belonged to you, whether the evidence was properly preserved, and whether the claimed timeline is consistent.
Can Police Build a Case Without a Positive Blood Test?
Yes. Prosecutors may rely on driving observations, officer testimony, video, statements, roadside exercises, a DRE opinion, witness testimony, physical evidence, or an alleged refusal.
Colorado’s express consent law authorizes a requested blood, breath, saliva, or urine test when an officer has probable cause to believe that a driver committed DUI or DWAI. A refusal may be admitted in court and may support driver’s license consequences.
A refusal does not prove impairment by itself. Your attorney may review:
- The wording and timing of the advisement
• Whether the officer made a clear request
• Your response and whether it was accurately recorded
• Medical limitations that affected your ability to complete a test
• Confusion, language barriers, or hearing issues
• Whether police later obtained a warrant
• Whether the collection process complied with the warrant
How a Colorado Drug DUI Lawyer Reviews the Evidence
A careful defense review asks whether the pieces fit together or only appear persuasive when viewed separately. Your attorney may:
- Compare police reports with every available recording
• Obtain dispatch records and laboratory documents
• Review the DRE report and the officer’s training history
• Inspect or photograph the stop location
• Interview passengers and other witnesses
• Review medical history and prescription information
• Consult a toxicologist when the scientific issues require it
• Examine the legality of the stop, arrest, search, and chemical test
• Determine whether prosecutors can prove impairment rather than drug presence alone
The strongest review follows the entire timeline, from the first claimed driving error through the final laboratory report.
The firm’s DUI frequently asked questions are available at:
https://www.hebetsmccallin.com/frequently-asked-questions-about-duis/
What You Can Preserve After a Drug DUI Arrest
Evidence can disappear quickly. Keep the paperwork provided by police, the court, the jail, the hospital, and the Colorado Division of Motor Vehicles.
You should also preserve:
- Event tickets, receipts, and parking records
• Messages and location data that help establish timing
• Photographs of the roadway, shoulder, weather, or lighting
• Prescription labels and pharmacy records
• Medical information related to balance, vision, speech, or coordination
• Names and contact information for passengers or witnesses
• Clothing and footwear worn during roadside exercises
• Notes describing what you remember about the stop and testing
Do not alter records or post details about the case on social media. Speak with an attorney before providing additional statements about the allegation.
Speak With a Colorado Drug DUI Defense Attorney
A drug DUI allegation may involve police judgment, scientific testing, constitutional questions, and separate court and driver’s license deadlines. Hebets & McCallin P.C. represents people facing DUI and DWAI allegations in Denver, Colorado, and nearby areas.
The firm’s attorneys are former prosecutors with experience reviewing traffic stops, body-camera footage, roadside exercises, DRE evaluations, blood draws, toxicology records, searches, and possible defenses. Every case depends on its own facts, and no particular result can be promised.
Call 303-854-6006 for a free consultation, or visit:
https://www.hebetsmccallin.com/contact-us/
This article is for general informational purposes only and is not legal advice. Every case is different. Consult an attorney about your specific circumstances.
