In most DUI trials where someone has been seriously injured or killed, a defendant has the right to a decision by a jury of twelve–and all of those jurors have to agree that the defendant is guilty before there is a conviction. One holdout can grind the entire proceeding to a halt. A jury that's stuck between innocence and guilt is said to be deadlocked or "hung." It is important to understand what this means if it happens to you, because what happens next can drastically affect the rest of your life.
Is it time to bargain if the jury is hung?
Usually, the jury will let the judge know that they are at a sticking point and aren't able to come to a verdict. At that point, it's rare for a judge not to send the jury back for at least a little more deliberation, in the hopes that they'll get past that point and come to a verdict after all. Trials are difficult and expensive, so it's in the best interests of the court for a decision to be made.
During this time, it isn't uncommon for the subject of a plea agreement to come up. At this point, however, neither you nor the attorneys involved know the way that the verdict is split. It could be fairly evenly split, it could be mostly in your favor, or it could be mostly against you.
If you are offered a plea, you are essentially giving up the possibility that you'll be found not guilty. This is a decision that you have to consider carefully, in consultation with your attorneys. Keep in mind, however, that if you decide to plead guilty and regret the decision later, you will have lost the opportunity to file any appeals.
What can happen next?
In some states, the judge can choose to deliver what is known as an Allen charge. This is essentially an admonishment that reminds the jurors that strongly held convictions don't necessarily equate reason. It asks those in the minority to consider why they haven't allowed themselves to be swayed by the majority. It reminds the jurors that there's already been a considerable amount of time, expense, and effort put into the case. It's an exceptionally powerful speech.
In other states, the Allen charge is considered too emotional and coercive to read to jurors. However, the judge can still ask the jury to try again. The judge can also interview the jurors independently, in order to try to determine why there is a deadlock, to see if it can be overcome.
If the jury still can't come to a verdict, the judge will usually declare a mistrial and dismiss the case. A mistrial is a formal declaration that a trial has failed to come to a conclusion. Unfortunately, that doesn't necessarily mean that the case is over.
Depending on the circumstances, your attorney may ask the judge to declare a mistrial with prejudice, which means that it can't be retried at a later time. This is relatively rare, however. Most cases are dismissed without prejudice, which means that it is ultimately up to the prosecutor whether or not to retry the case. If that happens, you'll have to go through the stress and expense of another trial.
One advantage to this, however, is that after the mistrial it's possible to find out what the split in the jury was like, whether it favored you or the prosecution. At that point, you'll have more information and may be able to clearly tell you if you want to discuss a plea with the prosecution or not. In addition, the prosecution may be more willing to give you a favorable plea, rather than to risk another mistrial or a losing case.
For more information on how mistrials work, discuss the situation with your criminal attorney.