One of the more controversial issues in Colorado evidence law is use of other past bad acts. Can the prosecution use other acts evidence to prove that the accused committed the charged offenses in a current case? This debate extends into cases involving all types of charges in Colorado criminal law – including driving while intoxicated (DUI) and driving while ability impaired (DWAI).
Colorado law does not permit the prosecution to present past acts to show that a defendant committed an offense in more current times because he or she did the same or similar bad act on a past occasion. CRE 404(b)(1) states “[e]vidence of any other crime, wrong, or act is not admissible to prove a person’s character in order to show that on a particular occasion the person acted in conformity with the character.” This is called “propensity evidence” and is inadmissible at trial.[i] Propensity evidence basically says that, because a defendant acted badly on a past occasion, he or she must have done the more recent crime.
However, Colorado evidence rules do allow other acts evidence to be used for select purposes, such as proving motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.[ii] For example, if a perpetrator commits a crime in a unique or specialized way, the prosecution may be allowed to use past instances of the individual doing the same or similar offense on another occasion to show preparation, planning or identity.
How does other acts evidence relate to charges of DUI or DWAI? The following examples show how this evidence may be used. If a suspect is arrested for a drunk driving related crime and makes a statement that he or she had previously been sober for a long period of time prior to his or her arrest, the statement may be admitted at trial to demonstrate that the accused had knowledge of his or her impaired state, and can also show consciousness of guilt.[iii] A defendant’s past use of alcohol or illicit drugs may be admitted under CRE 404(b) at a DUI or DWAI trial if he or she mounts a defense that the accused had never previously ingested alcohol or illegal drugs.[iv]
Generally speaking, however, Colorado courts are very hesitant to permit the prosecution to use evidence of a defendant’s past instances of driving while intoxicated as other acts evidence at trial. Such evidence has a tendency to show that the accused person cannot comply with the law and may demonstrate struggles with alcohol or illicit drugs.[v] Therefore, the prejudice of this information far outweighs any probative value or benefit it may have for the prosecution.
Furthermore, the crimes of DUI or DWAI typically involve few if any details that make the commission of them unique or special, which might make past other acts admissible for purposes of identity or plan. Thus, admission of past DUI or DWAI convictions would merely be offered for propensity purposes – it would demonstrate that, because a defendant did the act before, he or she likely did it again in the current case.
Colorado evidence laws and rules can be very complex. This complexity especially applies to past other acts and their possible use in a current case. If you are facing DUI or DWAI in Colorado and have concerns about past conduct possibly being used at trial against you, contact Mile High Legal and let our professionals help you obtain the fairest possible outcome to your matter.
[i] Masters v. People, 58 P.3d 979, 995 (Colo. 2002)
[ii] CRE 404(b)(2)
[iii] People v. Kennedy, 2019 Colo. App. LEXIS 3177
[iv] People v. Vandresar, 2005 Colo. App. LEXIS 2386
[v] People v. Schlehuber, 2025 COA 50, ¶ 51
