A DUI (or DWI in some states) case proceeds just like any other criminal case. Both sides argue over the facts and the evidence, as well as file various legal documents with the court.
One kind of document they may file is the pretrial motion. These motions get filed after a preliminary hearing but—as the name suggests—before the trial starts.
The decisions the court makes about these motions can have a significant effect on how the trial goes, including the penalties you may face.
A pretrial motion is a request for the court to make a specific ruling or take a specific action before the trial begins. The motion includes arguments outlining why the judge should do what you are asking.
In general, pretrial motions set the scope of the upcoming trial. They determine what evidence and legal arguments will be allowed at trial.
There is also usually a strict filing deadline for them. The court will usually not even consider a motion filed after the deadline.
Additionally, both the prosecution and the defense in a DUI case may file pretrial motions.
There are many different kinds of pretrial motions. These frequently involve getting or using/not using certain pieces of evidence. Common pretrial motions your lawyer may file in a DUI case include the following:
Motion to suppress. This motion is just what it sounds like: a request to exclude certain evidence from trial. This evidence can include a confession you made at the scene. Evidence must also meet certain legal requirements in order to be admissible at trial. Consequently, this motion tries to show that some piece(s) of evidence do not meet these requirements. There are several reasons often given to suppress evidence:
Pitchless motion. If you believe the arresting officer behaved inappropriately (planted evidence, profiled you, etc.), you can request the judge review his/her personnel file for a history of similar misconduct. If the officer has done the same thing before, this fact can be used to discredit him or her. This might even be enough to get the case thrown out.
Discovery motion. In most cases, both sides engage in an informal discovery process, sharing relevant evidence. If the prosecution is refusing to give you certain evidence, you can file a motion asking the judge to order the prosecutor to turn it over.
Motion to strike prior DUIs. This motion asks the court to disregard other DUI convictions you may have when deciding your sentence.
Motion to dismiss. This is an argument that your case should not go to trial. Your lawyer can file this even if you had a preliminary hearing where the judge found probable cause. For example, you may use this if the prosecutor filed different charges than those originally proposed and the evidence presented at your hearing does not support the new charges.
Why can pretrial motions be helpful in DUI cases?
Even if unsuccessful, every motion filed enhances your case's record. Information introduced this way may also be useful in limiting the officer's testimony during the trial.
The rules governing pretrial motions can get complicated and vary by state. Additionally, federal courts have yet another set of rules. And remember you generally have strict filing deadlines to meet.
It's important to have a lawyer experienced with DUI cases to advise you on your options and get the right motions filed the right way and on time. Although this does not guarantee they will succeed, it can make it more likely.