When can DUI charges in Florida be dropped?

It is not easy to get DUI charges dropped under Florida DUI law. Like most states, Florida takes DUIs very seriously and a prosecutor is likely going to either arrange a plea bargain with you or prosecute the case. In order to have charges dropped, you'll need to either convince the prosecutor not to prosecute, or you will have to convince a judge to dismiss the charges when the prosecutor does file the case. Your ability to do this is going to depend on what arguments, if any, you have to keep evidence out or to show that the evidence the prosecutor has is insufficient to prove your guilt. 

Since DUI charges are criminal charges under Florida law, a prosecutor who takes the case to trial has a burden of proof. Like in any criminal case, he or she must present evidence to prove your guilt beyond a reasonable doubt. If you are able to keep some of their evidence out, then the prosecutor is not going to be able to meet his burden of proof. This means that if you can prove the evidence against you was obtained in violation of your fourth amendment rights against unreasonable search and seizure (i.e. it was obtained without a warrant or without probable cause), then you can create a situation where they have no evidence. If they have no evidence, the charges will need to be dropped: the prosecutor will either realize this and drop them or your attorney can file a motion for dismissal and the judge will drop the case. 

This is only one example of a way to get DUI charges dropped and there may be others. The best thing you can do is consult with a lawyer who can provide you with guidance on how to proceed.