Pre-trial motions for a drunk driving case are submitted by the defendant's attorney after the arraignment, and, if applicable, the preliminary hearing. These motions are used to set boundaries for the trial before the trial begins. The defense attorney submits pre-trial motions on behalf of his client in order to benefit the defendant and his case. There are a variety of pre-trial motions in a drunk driving case that can be made. Acceptable pre-trial motions for DUI cases vary by state. The following motions are among the possibilities:

1. Motion to Suppress

This motion seeks to suppress evidence for the drunk driving incident that was collected improperly or illegally by the police officer. For example, if the police officer pulled someone over based solely on an anonymous tip received, this might make any evidence collected as a result of being pulled over (virtually everything) inadmissible in court.

2. Discovery Motion

This motion requires the prosecution to make all evidence for their case available to the defense. Usually this happens on an informal basis and no motion is required. If either side refuses to disclose a piece of evidence, however, a formal discovery motion is submitted.

3. Motion to Strike Prior DUI Convictions

This motion seeks to prohibit any past DUI convictions from being taken into account during the sentencing because penalties for DUI cases become more severe with each subsequent conviction. Normally the prior DUI convictions need to have happened 10 or more years ago.

4. Pitchess Motion

This motion allows the defense access to the police officer's personnel file. This is used to prove the defendant was mistreated by the officer. Complaints in the officer's file that might help prove this include excessive force, false arrest, and racial bias. However, this is a difficult motion to attain and there needs to be a specific fact about the case to convince the judge to allow examination into an officer's past actions.

If many of these pre-trial motions are successful, it is likely that a drunk driving case will be dismissed before it goes to trial.