Criminal defense attorneys in California and around the country challenge toxicology evidence or question the behavior of the police officers involved in drunk driving cases, but there are situations where they may choose to mount affirmative defenses. The defendants in these cases admit that they got behind the wheel after consuming alcohol or taking drugs, but they introduce evidence that they believe will negate their criminal liability. The affirmative defenses mounted in drunk driving cases fall into two broad categories. Defendants either argue that they did not know they were impaired, or they claim that they got behind the wheel because they had no choice.
Duress and necessity
DUI defendants mount defenses based on duress when they claim that they were coerced into driving while impaired. Necessity is a far more common affirmative defense in DUI cases. When this defense is mounted, the defendant argues that they only drove while intoxicated to prevent a greater harm. If a person who has been drinking is arrested while rushing an injured friend to an emergency room, they could mount an affirmative defense based on necessity.
Involuntary intoxication
Involuntary intoxication is an affirmative defense mounted by DUI defendants who had no reason to believe that they were impaired. People can become involuntarily intoxicated if their food or drinks are “spiked” with drugs or alcohol is added to nonalcoholic beverages like soda. Involuntary intoxication can also be caused by certain medical conditions.
Affirmative defenses are rarely mounted in court
Affirmative defenses are rarely heard by juries in drunk driving cases because prosecutors usually take a lenient approach when presented with evidence that establishes duress, necessity or involuntary intoxication. This happens because trials are expensive, juries are sympathetic to defendants who did not intend to cause harm and prosecutors do not like to lose. When an affirmative defense is mounted in a DUI prosecution, the case is unlikely to go to court.
