Sometimes, even if a person knows they are drunk, they have to drive. This defense is known as "necessity" and also known as justification (but with a different standard). It is very limited and your Chester County DUI lawyer better know the in's and out's of this potential defense and use it if necessary to help keep you out of jail and keep your license.
The elements of a successful justification defense have been restated as follows: (1) that the actor was faced with a clear and imminent harm, not one which is debatable or speculative, (2) that the actor could reasonably expect that the actor's actions would be effective in avoiding this greater harm, (3) that there is no legal alternative which will be effective in abating the harm, and, (4) that the legislature has not acted to preclude the defense by a clear and deliberate choice regarding the values at issue.
Necessity may be raised as a defense and excuse liability where the conduct which the actor believes to be necessary to avoid a harm or evil to himself or to another is justifiable if: (1) the harm or evil sought to be avoided by such conduct is greater than that sought to be prevented by the law defining the offense charged; (2) neither this title nor other law defining the offense provides exceptions or defenses dealing with the specific situation involved; and (3) a legislative purpose to exclude that justification claimed or does not otherwise plainly appear.
As with any offer of proof, it is essential that the offer of proof, justifying an instruction on justification by necessity as a defense to a crime charged, meet a minimum standard as to each element of the defense so that if a jury finds it to be true, it would support the affirmative defense--here that of necessity. This threshold requirement is fashioned to conserve the resources required in conducting jury trials by limiting evidence in a trial to that directed at the elements of the crime or at affirmative defenses raised by the defendant. Where the proffered evidence supporting one element of the defense is insufficient to sustain the defense, even if believed, the trial court has the right to deny use of the defense and not burden the jury with testimony supporting other elements of the defense.
In Commonwealth v. Manera, 2003 PA Super 215 (Pa. Super. Ct. 2003), the the trial court found that defendant's conduct would have supported a justification defense, except that this statutory defense was unavailable for prosecutions under 75 Pa. Cons. Stat. Ann. § 1543(b). The appellate court ruled that under 18 Pa. Cons. Stat. Ann. § 502, necessity afforded a general justification for conduct that otherwise would have been an offense. The justification offense was generally applicable to all offenses, absent clear legislative intent to the contrary. There was no indication that the legislature intended to abrogate the justification defense under 75 Pa. Cons. Stat. Ann. § 1543(b). The legislature could have expressly abrogated the justification defense, but did not do so. This case opened up the defense to many crimes, including DUI.
In Commonwealth v. Billings, 2002 PA Super 40, P5 (Pa. Super. Ct. 2002), the defendant was convicted of a DUI. The court found that the "no alternative" portion of the defense was not met,
Appellant testified that he was in the car when his companion hit a small animal and became too upset to drive. Even if Appellant faced imminent harm by oncoming traffic, he would still not be justified in driving the car home. He would, at most, be justified, out of necessity, in parking the car on the side of the road so as not to cause an accident. Appellant had other reasonable options to driving the vehicle while intoxicated. For example, he could have activated the emergency flashers and given his companion an opportunity to regain her composure. Clearly, the defense of necessity was not met.