A person with a charge of driving under the influence of substances (Driving Under Influence [DUI] or Driving While Intoxicated [DWI]) has some defense options available. There are some affirmative defenses in limited circumstances, even when the evidence supports the charge. But more often defend a charge of driving while intoxicated attacking the officer’s observations of what happened prior to arrest or question the integrity of the test, as the accuracy of the breathalyzer test. DUI laws differ from state to state and each case has different facts, so that it is best to consult an attorney.
Affirmative defenses to DUI charges
- Need: When a person must drive to prevent a greater evil. The driver must show that he had no choice and that the “greater evil” wanted to avoid was more serious than the possible damage that could cause a DUI.
- Coercion: When the defendant leads to avoid serious injury or death. For example, someone forces a person intoxicated driving under threat of force.
- Error of fact: When a person believes in good faith that is not intoxicated. For example, have valid reasons to believe that the toxic effect of your prescription has disappeared.
- Involuntary intoxication: When a person has consumed alcohol without their knowledge. For example, if an unrecognizable amount of alcohol was introduced to the bowl of punch at a party.
Common defenses for drunk driving cases
- Improper arrest: Is one of the most commonly used by defense attorneys in DUI cases arguments and involves the allegation that the officer had no probable cause to stop the vehicle.
- Administration / Precision sobriety test: You can have an arrest for drug if founded on a sobriety test improperly administered or erroneous results. The horizontal nest games test, which detects eye movements often associated with food poisoning, often questioned.
- Administration / Precision exam portable breathalyzer: The lawyer can question the breathalyzer test administration conducted at the scene of the offense (egg was the officer trained?) or if there were influential factors, such as vomiting or indigestion. Moreover, the defense may question whether the device with which the test was performed was properly calibrated and maintained.
- Administration / Precision standard of breathalyzer exam: Similar to the defense No. 3, but refers to more accurate tests using breathalyzers at the station after making an arrest.
- Management / Custody chain of the blood test: This defense questions the administration of blood or if it was altered or handled incorrectly in the chain of custody.
- Elevation of blood alcohol concentration: The defense contends that the blood alcohol concentration was below the legal limit when the accused drove, but increased between the time when the vehicle was stopped and the breathalyzer exam was administered. This is possible when the system has not fully absorbed recently consumed alcohol until the time of the breathalyzer test.
Less common defenses:
- The defendant was not the driver: One may question whether the person with the DUI charge was actually driving at the time. Perhaps the passenger, believing he was sober, switched places with the driver but failed in the field sobriety test or breathalyzer.
- Inadequate police actions: This defense can include evidence or testimony that the officer violated the civil rights of the accused (falsified a DUI report or had inappropriate behavior).
- Conviction for Driving Under the Influence (DUI)
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