Colorado Express Consent Law Explained: Roadside vs.
Evidentiary Tests

Colorado’s Express Consent Law binds drivers to submit to chemical testing once they accept a driver’s license from the DMV, but many motorists don’t realize what this agreement entails until a traffic stop occurs. The law distinguishes between roadside screening tests and post-arrest evidentiary tests, each carrying different legal consequences under Colorado Revised Statutes § 42-4-1301.1. Understanding these differences helps drivers protect their rights, avoid costly mistakes during stops, and prevent automatic license suspensions.

Roadside tests, such as the walk-and-turn, one-leg stand, and horizontal gaze nystagmus, are voluntary pre-arrest screenings used to establish probable cause. Refusing them does not trigger Express Consent penalties. Evidentiary tests, breath, blood, or urine, occur after arrest, and refusal can lead to administrative license suspensions of one year for a first offense and two years for subsequent refusals.

Knowing when consent legally applies allows drivers to navigate stops confidently while safeguarding their driving privileges.

What Is Colorado’s Express Consent Law?

Colorado’s Express Consent Law requires that any driver on state roads agree to submit to chemical testing if a police officer suspects DUI or DWI. This agreement is automatic when you obtain a Colorado driver’s license—not just at the traffic stop.

Under this law, law enforcement can request breath, blood, or urine tests to measure blood alcohol content (BAC) or detect controlled substances such as marijuana, cocaine, or prescription drugs. Refusing these post-arrest DUI tests triggers automatic license suspension through the Colorado DMV, even before any criminal conviction.

Importantly, the Express Consent Law applies only to evidentiary tests conducted after arrest. Preliminary Breath Tests (PBTs) at the roadside are voluntary and do not carry automatic DMV penalties. Understanding the difference between mandatory post-arrest chemical tests and voluntary roadside screenings helps Colorado drivers protect their rights while complying with state DUI laws.

The Two Types of DUI Tests in Colorado

Law enforcement uses two main DUI testing methods in Colorado: roadside screening tests before arrest and evidentiary chemical tests after arrest. Knowing the distinction is critical under Colorado DUI law.

Preliminary Breath Tests (PBTs) are handheld devices officers use on the roadside. These tests provide a quick estimate of BAC and help determine probable cause for a DUI arrest. PBT results are not admissible in court, and drivers may legally refuse these tests without risking automatic license suspension.

Evidentiary tests are conducted at police stations or medical facilities following a DUI arrest. These include:

• Breath tests with calibrated instruments like the Intoxilyzer 9000

• Blood tests performed by certified medical staff

• Urine tests analyzed in state-approved laboratories

These tests follow strict protocols, producing legally admissible evidence for DUI prosecution. Under the Express Consent Law, refusing an evidentiary test automatically triggers DMV license suspension, independent of the criminal court outcome.

Understanding the difference between roadside PBTs and station evidentiary tests is essential for navigating Colorado DUI investigations, protecting your driving record, and preparing a proper legal defense.

Preliminary Roadside Breath Tests: Your Rights and Options

When a police officer asks a driver to blow into a portable breath device during a traffic stop, that driver has the legal right to refuse. Colorado law does not require drivers to submit to preliminary roadside breath tests. Declining these tests carries no automatic penalties or license suspensions.

These portable devices serve as investigative tools for police officers. Law enforcement uses them to establish probable cause for a DUI arrest, not as evidence for prosecution in court. Officers may request such tests when they suspect impaired driving. Common indicators include weaving between lanes, bloodshot eyes, alcohol odor on breath, slurred speech, or driver admissions about drinking.

The driver’s refusal cannot be mentioned or used against them in criminal court proceedings. This legal protection makes preliminary tests different from evidentiary testing. Evidentiary breath or blood tests occur after arrest at the police station or medical facility. Colorado’s Express Consent Law requires submission to these post-arrest tests. Refusing evidentiary tests triggers mandatory license revocation for one year or longer.

The distinction between preliminary roadside tests and post-arrest evidentiary tests matters for legal protection. Preliminary tests happen before arrest and are voluntary. Evidentiary tests happen after arrest and are mandatory under state law. Knowing this difference helps drivers make informed decisions during traffic stops.

Drivers can protect their legal interests by understanding which tests they must take and which tests they can refuse without consequences. This information applies specifically to Colorado driving laws and may differ in other states. Drivers should consult with a qualified DUI defense attorney to understand how these rules apply to their specific situation.

Evidentiary Chemical Tests: Blood, Breath, and Urine

Under Colorado’s Express Consent Law, drivers arrested for DUI must submit to evidentiary chemical tests. Unlike voluntary roadside screenings, these tests are mandatory, and officers must inform drivers of their legal obligations under Colorado Revised Statutes § 42-4-1301.1.

• Breath Tests: Breath tests, typically using an Intoxilyzer 9000, measure alcohol vapor in exhaled air to calculate blood alcohol concentration (BAC. Breath tests detect ethanol only and cannot identify drugs or prescription medications.

• Blood Tests: Medical professionals draw blood samples in sterile conditions. Laboratory analysis determines BAC and detects controlled substances, including marijuana (THC), cocaine, opioids, and prescription drugs. Blood tests provide precise information about both the type and amount of substances in the bloodstream at the time of collection.

• Urine Tests: Urine samples identify drug metabolites, breakdown products from substances used, but cannot determine current impairment or the exact time of consumption. Courts generally consider urine results less reliable than blood or breath tests.

Refusing an evidentiary test triggers automatic license revocation through the Colorado DMV. First-time refusals result in a one-year suspension, enforced independently of criminal court outcomes. Subsequent refusals carry longer revocation periods.

Chemical test results are key evidence in DUI prosecutions. A BAC above 0.08% or the presence of controlled substances strengthens per se DUI charges. Defense attorneys may challenge test accuracy, collection methods, or chain-of-custody documentation, but refusal itself carries serious administrative penalties.

Understanding your options and obligations under the Express Consent Law is critical for protecting your driving privileges and preparing an effective DUI defense.

When Does Express Consent Actually Apply?

Colorado’s Express Consent Law applies only after a legal DUI or DWAI arrest and covers post-arrest chemical tests of blood, breath, or urine. Many drivers mistakenly believe it applies to roadside screenings, but preliminary tests and field sobriety exercises are voluntary and not governed by express consent.

The law takes effect when:

• Officers have probable cause to believe a driver is impaired by alcohol or drugs.

• The driver is lawfully arrested for DUI or DWAI.

• Law enforcement requests a formal evidentiary test at a police station, jail, or medical facility.

Express consent also applies at sobriety checkpoints if impairment signs (slurred speech, bloodshot eyes, alcohol odor) justify an arrest.

Understanding the distinction between voluntary roadside tests and mandatory post-arrest chemical tests helps drivers safeguard their legal rights, constitutional protections, and driving privileges during DUI investigations in Colorado.

Probable Cause Requirements for Chemical Testing

To understand when the Express Consent Law applies, you need to know what allows a police officer to arrest someone and request chemical testing. Colorado law states that officers must have probable cause before they can legally arrest a driver for DUI (Driving Under the Influence) or DWAI (Driving While Ability Impaired).

Probable cause means more than just a guess; the officer needs enough facts and circumstances that would make a reasonable person believe the driver broke impaired driving laws.

Officers build probable cause through things they can observe and document: the driver weaving between lanes, the smell of alcohol or marijuana in the vehicle, unclear speech patterns, poor performance on roadside sobriety tests, or the driver admitting they consumed alcohol or drugs.

When officers fail to establish probable cause, the arrest becomes illegal. This means the Express Consent Law may not apply to that situation. Police officers cannot randomly demand breath tests, blood tests, or urine tests from drivers.

The Fourth Amendment to the U.S. Constitution protects citizens from unreasonable searches and seizures, which requires officers to meet the probable cause standard before making DUI arrests and requesting chemical evidence testing.

Consequences of Refusing a Roadside Screening Test

When a driver says no to a roadside screening test (like a preliminary breath test or field sobriety exercises), Colorado law prevents prosecutors from using that refusal to prove guilt in a DUI criminal case. The refusal itself does not count as evidence that the driver was impaired by alcohol or drugs.

The refusal can still affect what happens during the traffic stop. Police officers may use other signs of impairment, such as bloodshot eyes, slurred speech, odor of alcohol, or unsafe driving behavior, to decide whether to make an arrest.

After arrest, officers typically ask the driver to submit to an official chemical test (breath, blood, or urine analysis) at a police station, hospital, or testing facility. This second test falls under Colorado’s Express Consent Law and carries different legal consequences if refused.

Defense lawyers representing DUI defendants must examine how refusing the roadside test shapes the available evidence. Without roadside test results, prosecutors must rely entirely on the officer’s observations, witness statements, dashboard camera footage, body camera recordings, and any chemical test results obtained after arrest.

In some situations, refusing the roadside test removes potentially damaging evidence from the case. In other situations, the absence of test results matters less because the officer documented strong evidence of intoxication through other means.

The strength of a DUI prosecution depends on the complete picture of evidence: the reason for the traffic stop, the driver’s behavior and appearance, performance on any field sobriety tests the driver agreed to perform, statements made by the driver, and results from post-arrest chemical testing.

How Test Refusals Impact Your Criminal DUI Case

Refusing a roadside test affects two separate legal areas: your criminal DUI case and your driver’s license. In criminal court, prosecutors can still charge you based on observable impairment, field sobriety performance, and witness testimony. Courts protect your right to refuse voluntary tests, meaning refusal cannot be used to suggest guilt.

Your defense attorney must address both the DMV license suspension and the criminal case independently. Each follows different rules, timelines, and procedures, so a coordinated legal strategy is essential.

Criminal prosecutions focus on physical evidence of intoxication: failed sobriety tests, slurred speech, alcohol odor, and behavior observed by law enforcement. Skilled attorneys examine whether officers followed proper procedures during the stop, testing, and arrest. Any procedural errors can weaken the case, even without chemical test results.

Penalties for Refusing an Evidentiary Test

Colorado law punishes drivers who refuse chemical testing after police arrest them for drunk driving. The state’s Department of Motor Vehicles takes away your driver’s license right away. A first refusal means losing your license for one year. A second refusal within five years costs you two years without a license. A third or fourth refusal means three years without driving privileges.

The state offers no way to get your license back early when you refuse testing. You cannot get a work permit, probationary license, or restricted driving privileges during this suspension period.

Refusing the test creates problems in court, too. The prosecutor can tell the jury you said no to testing. Jurors often think refusing means you knew you were guilty. This evidence of refusal works against you during your trial.

If the court convicts you of DUI, the judge treats your refusal as a reason to give you a harsher punishment. The refusal becomes what lawyers call an “aggravating factor” at sentencing.

These penalties start immediately and follow you into the courtroom. You face automatic license suspension from the DMV and possible jail time from criminal court. Both consequences happen because of one refusal decision.

Understanding these specific punishments helps drivers make informed choices when police request breath, blood, or urine testing. The stakes include your driving privileges, your freedom, and your criminal record. Each consequence carries serious impacts on your daily life, job, and family responsibilities.

How License Revocation Works After Test Refusal

When a driver refuses a breath, blood, or urine test, the license revocation process begins immediately. The arresting officer completes a Notice of Revocation form, which both informs the driver of the pending suspension and serves as a temporary license valid for seven days.

During this seven-day window, the driver can request a hearing with the Colorado Department of Motor Vehicles (DMV) to challenge the revocation. Missing this deadline results in automatic license suspension without a hearing.

The DMV hearing is separate from any criminal DUI case and is conducted by a hearing officer, not a judge. The officer’s role is to determine whether the police had a valid reason to request the chemical test and whether the driver actually refused. Both police reports and witness statements are reviewed, and the driver may present evidence and legal representation.

If the hearing officer upholds the revocation, the driver’s license is suspended. Penalties vary by prior history: a first refusal triggers a minimum one-year suspension, while second or subsequent refusals within five years result in longer suspension periods. These administrative penalties apply independently of criminal court outcomes; even if a driver is never convicted of DUI, refusing a chemical test automatically jeopardizes driving privileges.

The One-Year Suspension for First-Time Refusal

A driver who refuses a breath test, blood test, or urine test for the first time will lose driving privileges for one full year. This one-year license suspension happens even if the driver’s blood alcohol concentration (BAC) would have been below 0.08% (the legal limit for adults). The Department of Motor Vehicles (DMV) issues this administrative penalty as a separate action from any criminal DUI charges in court.

Colorado law does not allow a hardship license, work permit, or any restricted driving privileges during this one-year revocation period for test refusal. The suspension starts seven days after a law enforcement officer gives the driver the notice of revocation form. A driver can stop this timeline by requesting an administrative hearing with the DMV within those seven days. Winning at this DMV hearing is the only way to prevent the suspension.

Drivers need to know that refusing chemical testing results in specific penalties that are usually worse than the penalties for taking the test and failing it. The refusal suspension lasts longer than most first-offense DUI suspensions.

Law enforcement officers must inform drivers about these express consent laws before requesting a chemical test. When a person operates a motor vehicle in Colorado, they automatically give consent to chemical testing if an officer has probable cause to believe they are driving under the influence of alcohol or drugs.

Can You Change Your Mind After Refusing a Test?

When a driver says no to a breathalyzer test or blood test, changing that answer creates serious legal problems. Colorado’s drunk driving laws do not give clear rules about whether saying yes later can erase the first no. Police officers write down the refusal right away in their reports. This starts the punishment process with the DMV (Department of Motor Vehicles).

A driver might try to agree to the test after refusing it. The police officer can say no to giving the test at that point. The penalties for refusing still apply in most cases.

The details of when and how someone changes their mind do matter. Courts look at whether the person clearly refused the first time. The DMV bases its decision to suspend a driver’s license on that first refusal. The DMV controls license suspensions for refusing chemical tests in Colorado.

Drivers need to know that trying to take back a refusal does not protect them from penalties. The breathalyzer or blood alcohol test refusal stays on record. The first choice to say no is the one that counts under Colorado’s implied consent law. This law says drivers agree to testing when they use Colorado roads.

Making the right choice the first time matters most. Chemical test refusals lead to automatic license suspension periods. These suspensions happen separately from any criminal DUI charges in court.

Medical Conditions and Chemical Testing Exceptions

Colorado’s express consent law requires drivers to take chemical tests when officers suspect impaired driving. Some medical conditions make these tests difficult or risky to complete.

Breathing Problems

People with serious lung diseases face real challenges with breath testing equipment. Severe asthma patients often cannot blow hard enough or long enough into breathalyzer devices.

Emphysema sufferers experience similar difficulties. The testing machines need strong, steady breath samples that these individuals physically cannot provide.

Blood Draw Concerns

Blood tests create problems for specific groups of drivers. Hemophilia patients risk dangerous bleeding from needle punctures because their blood does not clot properly.

People taking warfarin, heparin, or other anticoagulant medications face the same bleeding risks. These legitimate medical concerns affect a person’s safety during blood sample collection.

No Automatic Exemptions

Colorado law does not excuse drivers from testing based solely on medical conditions. Every driver must make a good-faith effort to complete some form of chemical testing.

The law recognizes that medical issues exist, but still expects cooperation with the testing process.

Alternative Testing Options

Police officers can offer different testing methods when medical problems prevent one type of test. A driver who cannot complete a breath test may take a blood test instead.

Someone with bleeding disorders might take a breath test rather than give blood. Officers have the discretion to accommodate reasonable medical limitations while still collecting evidence of blood alcohol concentration or drug presence.

Protecting Your Rights

Drivers with medical conditions should take clear steps during traffic stops. Tell the officer about your specific condition right away.

Name the disease or medication causing the problem. Ask the officer to write down your medical explanation in the police report.

Request immediate evaluation by paramedics or emergency room doctors who can document your condition. Get written medical statements explaining why certain tests pose health risks.

Legal Consequences

The Division of Motor Vehicles can still revoke your license if you refuse all testing options. Medical conditions do not prevent revocation unless you have attempted every reasonable alternative.

Courts examine whether you made genuine efforts to comply despite your health limitations. Proper medical documentation becomes critical evidence in DMV hearings and criminal court proceedings.

Without clear proof of your medical condition and attempts to cooperate, judges often uphold license suspensions.

Making an Informed Decision During a DUI Stop

Drivers who face requests for chemical tests during DUI stops must think about two competing problems: following the law right now versus creating evidence that prosecutors might use against them later.

Colorado’s express consent statute requires drivers to submit to blood alcohol testing, but refusing the test brings automatic driver’s license suspension through the Department of Motor Vehicles. Taking the test might give prosecutors the blood alcohol concentration (BAC) results they need to prove drunk driving charges in criminal court.

Police officers at the roadside typically do not explain these competing legal consequences when they request breath or blood samples. This leaves drivers to make decisions with major legal outcomes while under stress and without legal advice.

The timing matters because drivers must decide before any attorney can arrive to help.

Two different types of tests create different legal situations. Preliminary breath tests happen at the roadside using portable breath testing devices. These screening tests are voluntary, and drivers can refuse them without automatic penalties.

Evidentiary chemical tests happen at the police station or hospital using more accurate equipment, like evidential breath testing machines or blood draws performed by medical professionals. State law requires drivers to submit to these evidentiary tests under the implied consent rule that comes with having a driver’s license.

Refusing the evidentiary test triggers Department of Revenue administrative actions, including license revocation periods of one year for first refusals and longer periods for subsequent refusals.

Taking the test and producing BAC results above Colorado’s legal limit of 0.08% for standard drivers or 0.04% for commercial vehicle operators gives prosecutors direct evidence of intoxication levels.

The decision involves weighing immediate Department of Motor Vehicles penalties from refusal against providing evidence for criminal prosecution through compliance.

Each path creates serious legal consequences requiring help from a DUI defense attorney after the testing decision gets made. Drivers benefit from understanding these rules before any traffic stop happens, since the law prohibits consultation with legal counsel before the testing decision must occur.

Seeking Legal Help

Anyone arrested for DUI in Colorado should contact a qualified DUI defense attorney immediately. The Express Consent Law affects both administrative DMV proceedings and criminal court cases, making expert legal guidance essential.

A DUI lawyer can review whether police followed proper procedures, including administering tests correctly, providing proper express consent warnings, and conducting the traffic stop lawfully. They can challenge BAC results, defend against test refusal allegations, and represent the driver at DMV hearings to protect driving privileges.

Prompt legal action helps build a strong defense, minimize penalties, and navigate Colorado’s complex system of implied consent rules, license revocations, and criminal DUI charges. Professional guidance is critical to ensure drivers’ rights are protected at every stage.