When Massachusetts residents plead not guilty to DUI or other criminal charges, the next step in the process is usually what is known as a preliminary or pretrial hearing. This is often referred to as a trial that takes place before a trial, but the two procedures have very different goals. During a trial, prosecutors must establish guilt beyond a reasonable doubt in order to prevail. During a preliminary hearing, they must only demonstrate that the evidence they have is sufficient to warrant a holding a trial.

There is no jury present during a preliminary hearing. Instead, a judge decides whether or not prosecutors have met the legal standard necessary. This is known as probable cause. Preliminary hearings are often concluded quickly, but they can last for several days when the case is a complex one, the validity of evidence is challenged by defense attorneys or questions are raised about the behavior of the police officers involved.

The key evidence in DUI cases is usually the report submitted by the arresting officer and the results of toxicology tests. This will generally be enough to establish probable cause, but drunk driving charges may be dismissed if defense attorneys can establish that traffic stops were unconstitutional, breath, blood or urine tests were not performed properly or police used poorly maintained equipment to conduct toxicology tests.

Most drunk driving cases are resolved through plea bargains before preliminary or pretrial hearings are held. Experienced criminal defense attorneys may encourage their clients to consider pleading guilty return for less severe penalties when the evidence against them is likely to meet the probable cause standard. During plea negotiations, attorneys could argue for a more lenient sentence by pointing out mitigating factors that paint their clients in a more favorable light such as a previously unblemished criminal record and genuine remorse.