Can the prosecutor just drop the DUI charges?

In theory, yes; in practice, no. The DUI statute says that a prosecutor may not reduce a DUI charge unless he or she puts on the record in open court the reasons for doing so. Because of this restriction, prosecutors rarely throw out a DUI case. About the only time is when we can convince the prosecutor that there is a technical problem with the arrest or the test results and that a motion to suppress or motion to dismiss would be granted. In short, it is a rare case where the prosecutor drops the charges.