A motion is a legalese word that basically means a request. When either side is filing a motion, that side is asking the judge to do something for them. A pre-trial motion made by the defense may sometimes be a request to rule that certain evidence be ruled not admissible in court at a trial against the accused. In a DUI case, this may be a chemical test like the breath test the police administer. Sometimes, it may be the words that the police claim the accused spoke during questioning.
Only an experienced attorney can decide what motions are available to file on behalf of the client. These decisions cannot be made lightly and must be fully thought out given that the hearing can affect what happens at a later trial. William Wolf has had decades of experience making these judgments and aggressively making motions to use to fight for a client to improve his or her chances at trial.