After the preliminary hearing and before a criminal case goes to trial, the prosecutor and the defense team usually appear before a criminal court judge and make pre-trial motions -- arguments that certain evidence should be kept out of the trial, that certain persons must or cannot testify, or that the case should be dismissed altogether.

Remember that most DUI cases do not reach the preliminary hearing stage. In the majority of such cases, the arraignment usually represents the first and last time the suspect will be in court, as most DUI suspects choose to plead guilty, especially if evidence of intoxication is strong.

Pre-trial motions are tools used by the government and the defense in an effort to set the boundaries for trial, should one take place: What physical evidence and testimony can be used? What legal arguments can and cannot be made? Is there any reason that the defendant should not be forced to stand trial?

What Arguments are Made During Pre-Trial Motions?

• The defense asks the judge to keep out of the case ("exclude") marijuana "joints" that the defense argues was obtained through an illegal search of the defendant's car.
• The defense argues that a confession made by the defendant should be excluded, because it was made to a police officer who failed to advise the defendant of his Miranda rights.
• The defense argues that Breathalyzer test results should be excluded, because the testing procedure used by the arresting officer was clearly flawed.

More information:

• Scientific Evidence: An Introduction
• Searches & Seizures: The Limitations of the Police