A motion hearing is a date requested by your DUI lawyer. It is an opportunity for your DUI / OVI lawyer to put the officers who conducted the investigation on the stand and ask them questions about how they conducted their investigation. It's purpose is to allow the judge to rule on whether the investigation, or parts of it, were conducted properly / legally. If the judge decides that certain parts of the investigation were not conducted properly / legally, the judge will rule those parts excluded or "suppressed" from trial, which means a jury will never see those parts of the investigation. What a jury is allowed to see at trial is crucial to the defense of your DUI / OVI. The more that is suppressed, the better for your case.