If a party is charged with driving under the influence of alcohol (DUI), driving while intoxicated (DWI) or operating under the influence (OUI), there are numerous defenses he can raise prior to trial by way of a motion to suppress evidence or to dismiss the charges or during trial.
Defendant denies operating vehicle
The defendant can deny that he was operating the vehicle. The prosecutor is required to prove not only that defendant was intoxicated, but that he was also operating the vehicle.
The defendant can argue that the officer lacked probable cause to stop the vehicle. Further, the defendant may argue that the officer lacked probable cause to detain and arrest him.
Miranda and implied consent warnings
After the officer arrests the defendant for DUI, any statements that the defendant may make after being taken into custody may be suppressed if the officer failed to give him Miranda warnings.
If the officer failed to advise the defendant of the implied consent warnings and the consequences of refusing to take a breath test, the breath test results may be suppressed.
Field sobriety tests
Results of field sobriety tests conducted by the officer may be suppressed. The defendant may argue that the officer was biased in his subjective conclusion that the defendant was intoxicated after administering the field sobriety tests. The defendant may also cite a physical condition that precluded him from performing the tests properly.
Blood-alcohol concentration test
This test is most often conducted at the scene of the arrest. The defendant is required to blow into a device which measures the amount of alcohol in the defendant's system. The defendant may argue that the test was defective or improperly conducted. The defendant may also argue that medication that he was taking affected the test results or that the test results were skewed because he had just had a drink.
Other chemical tests
The defendant may be required to submit to a blood or urine test after his arrest. The defendant may argue that either of the tests was not properly performed, biased, or inaccurate. The prosecution will be required to prove that the tests were accurate and not defective at the time that they were administered.
Copyright 2009 LexisNexis, a division of Reed Elsevier Inc.