I guess that's what I'm asking. Is the state being unprepared (for whatever reason) a legally supportable basis?
First, a little bit of context. In some states for many traffic matters the state is not represented by a prosecutor; instead the cop just shows up to testify as to what he/she observed you do that formed the basis for the traffic ticket and then you provide your defense. In some ways it is not unlike a small claims matter. And if the cop fails to show up those judges generally have the discetion to dismiss the matter, and often do.
But Colorado is not one of those states. An attorney from the prosecutor's office does appear to represent the state. The rules vary a bit depending on the nature of the traffic offense. In Colorado most traffic offenses are infractions that are treated as civil matters. But a violation of Colorado Revised Statutes (CRS) § 42-4-1402 (careless driving) is not one of those. It is instead a class 2 misdemeanor traffic offense, which is a criminal offense unless a person was injured or killed as a result of the careless driving, in which case it is a more serious offense.
So here, we have a misdemeanor charge and the prosecutor did appear and asked for a continuance. You could not have successfully moved for dismissal at that point. Contrary to a previous response, the judge would not have had the discretion to do that. Colorado has simplified procedures for most misdemeaors and petty offense cases. On your court appearance from the summons issued to you by the cop (the ticket functions as a summons) the applicable rule states “Trial may be held forthwith if the court calendar permits, immediate trial appears proper, and the parties do not request a continuance for good cause. Otherwise, the case shall be set for trial as soon as possible.” Colo. Rev. Stat. Ann. § 16-2-113. So it wasn’t ever assured that the trial would commence immediately to begin with. If the court calendar did not allow for it that day, the court would schedule the trial later.
As the rule also makes clear the parties may also move for continuance, too, for good cause. So here you would have had to object to the continuance at the time the request was pending (that is, while you were standing in front of the judge and before the judge ruled on the continuance) and either argue that the state did not have good cause or argued why your case would be prejudiced by the delay. The reason why the DA did not have the material he/she needed would matter, but generally if the problem was due to someone outside the DA's office (e.g. the police, a lab, or whatever) the court will consider the DA to have good cause for the continuance. As to prejudice, you would need to show the court that your defense would be hurt by the delay, e.g. a necessary witness would be unavailable, etc. Simply being inconvenienced by the delay is not prejudice to your case. Had the judge denied the continuance and had declared that it was ready to hear the case, you then could have moved to dismiss or for acquittal if the state then said it was not ready to present its case. Then the judge would have had to grant that request because the state didn't have the evidence to present to convict you.
You did not object so it’s too late now to try that. You’ll want to be prepared for whatever happens at the next court date, though.
As this is a misdemeanor criminal offense you I recommend that you get an attorney to represent you on this. The penalty for a class 2 misdemeanor traffic offense is a minimum of ten days imprisonment, or $150 fine, or both and the maximum is ninety days imprisonment, or $300 fine, or both. See CRS § 42-4-1701. The court may also impose community service in addition to that as well. So there is the potential for more than a fine if you are convicted. You could end up spending some days in jail and/or doing some community service time. The exact facts of your case and your driving history will matter in sentencing, as well as who the judge is. In addition to that, the conviction will cost you 4 points on your license (12 points in a year or 18 in two years will result in license suspension) and will also result in a huge increase in your auto insurance rates for the next couple of years. Given all that, it may be well worth it to have a lawyer help you with this to minimize the impact as much as possible.