When a person is charged with Driving Under the Influence (DUI) or Driving While Ability Impaired (DWAI) in Colorado, like all criminal defendants, the person accused has the constitutional right to force the prosecutor, at a trial before a judge or jury, to prove the defendant guilty beyond a reasonable doubt. The defendant can raise defenses, and have witnesses testify, but the burden is always on the prosecutor to prove the defendant’s guilt.

To prove the guilt of the accused, the prosecutor must present witnesses in the Court to testify at a trial. It is not normally sufficient for a potential prosecution witness to submit a written report, letter, or affidavit, as evidence as to the guilt of the person accused of DUI or DWAI. Except in specific circumstances such documents are not allowed, standing on their own, to be admitted as evidence at a trial. The witnesses for the prosecution must come to the Court and testify.

The right of a defendant to confront the prosecution witnesses is enshrined in the Sixth Amendment of the United States Constitution.  Specifically, the provision of the constitution provides that, “in all criminal prosecutions, the accused shall enjoy the right…to be confronted with the witness against him.”

The original seminal ruling as to the confrontation clause was contained in the 1895 ruling of the United States Supreme Court in Mattox v. United States. This Supreme Court holding sets forth that the Confrontation Clause of the Constitution, contained in the Sixth Amendment, is interpreted to: i) that prosecution witnesses would testify under oath and appreciate the seriousness of the trial; ii) to allow the accused to cross-examine witnesses who testify against the defendant, and iii) to allow jurors to assess the credibility of a prosecution witness by seeing the person, and hearing their testimony, in the Court.

In a prosecution against an individual Colorado driver for Driving Under the Influence (DUI), or Driving While Ability Impaired (DWAI) often a crucial aspect at a trial is the veracity of the test for alcohol intoxication. The prosecutor must show that a blood test was done in accordance with procedures that ensured an accurate final reading of the blood alcohol content (BAC). More specifically, how the blood sample was forwarded and received by the testing laboratory for testing, the established procedures of the laboratory and whether those procedures were followed in the particular test, who actually conducted the testing, the equipment utilized to conduct the test, the qualifications of the technician, the inherent margin of error for testing, etc.

For testing of breath samples the prosecutor often must show that that the equipment utilized to collect and analyze the breath sample (often the Intoxilyzer  9000) was reliable, that it had been maintained properly, that it has been calibrated and tested to ensure accurate readings, what would cause an inaccurate reading and how those causes for inaccurate readings were minimized, and state with some certainty that the blood alcohol content submitted as evidence could be deemed to be reliable.

Often the testimony of the technician, trained in the maintenance, calibration, and use of the alcohol testing apparatus is critical for the prosecution. A competent defense attorney, skilled in the representation of those charged with Driving Under the Influence (DUI) or Driving While Ability Impaired (DWAI) can, through insightful and persistent questioning in cross-examination, render the final blood alcohol content (BAC) test results subject to doubt as to their veracity. Conversely, if the technician is not compelled to testify, and the Court allows the introduction of documents to show the efficacy of the alcohol testing, the defense cannot cross-examine the technician, and judges and juries tend to simply believe that the testing documentation is accurate and reliable.

In Colorado, in an attempt to limit the need for laboratory technicians to testify in DUI and DWAI trails, and other trials whereby a laboratory testing professional would need to testify for the prosecution, the Colorado legislature passed C.R.S. § 16-3-309. (5).  This section of Colorado law is intended to place a burden on the defense, to potentially curtail the defendant’s right to confrontation of witnesses, and to potentially uncharacteristically allow the introduction of reports by criminal testing laboratories without the actual testimony of the technician in open court.

This provision of this Colorado law provides as follows:

Any report or copy thereof or the findings of the criminalistics laboratory shall be received in evidence in any court, preliminary hearing, or grand jury proceeding in the same manner and with the same force and effect as if the employee or technician of the criminalistics laboratory who accomplished the requested analysis, comparison, or identification had testified in person. Any party may request that such employee or technician testify in person at a criminal trial on behalf of the state before a jury or to the court, by notifying the witness and other party at least fourteen days before the date of such criminal trial.

In other words, the burden is on the defendant to affirmatively notify the Court, and the Prosecution, that the defendant wants the laboratory technician to testify at the Court and that the submittal of documentation setting forth the test conducted, and the test results, is not sufficient.

The provisions set forth in C.R.S. § 16-3-309. (5) provides a trap for the unwary DUI or DWAI defense counsel who believes that the general precept that the prosecution must present their case with witnesses, who can be cross-examined, and thereby potentially discredited, is applicable in DUI and DWAI prosecutions without further action by the defense counsel. A defendant in a Driving Under the Influence (DUI) or Driving While Ability Impaired (DWAI) matter needs to have experienced and knowledgeable defense counsel who fully understands the ramifications of different provisions of Colorado law including the force and effect of C.R.S. § 16-3-309. (5).

Legal Disclaimer – The information contained at this website is regarding Colorado criminal law is general content only and should not be relied upon for any specific Colorado criminal law situation. Information on this web site is not intended to be comprehensive and does not cover all the issues, nuances or ramifications related to the topic discussed. This web site may not be updated routinely to reflect the very most current Colorado law.

Individuals should consult an experienced Denver criminal or traffic lawyer for advice regarding an individual situation.

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