DUI law covers not only driving under the influence of alcohol, but also driving under the influence of drugs. There are two ways a driver can be charged with a DUI for drugs: First, if they are under the influence to the extent that they cannot drive the vehicle safely, and second, if they are driving with any amount of drugs in their system. Notably, this covers both legal and illegal narcotics. A person can be charged with a DUI even if they have a prescription for the drug, which makes no sense.
There are several available defenses to these kinds of DUI charges. If the officer is relying only on their judgement alone, a good defense is to question whether the officer is qualified to say whether or not the driver was too intoxicated to drive. Most adults generally have a good understanding of what a person looks like when they're too drunk to drive safely, but not everyone has the same kind of experience for marijuana, cocaine, or other illegal drugs. Because there are no roadside tests for most of these drugs, cops often rely only on their judgement, and this can be fought in court. Even if the police officer is qualified to say whether or not a driver is intoxicated, they have to prove conclusively and beyond a reasonable doubt that the driver was under the influence of drugs. Just because the officer can smell marijuana, for example, doesn't conclusively prove that a driver had been smoking.
The case can get more difficult if the defendant had a blood or urine test taken; in Illinois, you can face DUI charges anytime you drive with drugs in your system. Still, there are many possible defenses. To be admissible in Illinois, testing needs to comply with the Illinois State Police regulations. If the test was not properly taken, it cannot be used against you in court. You need to make it hard for the State to prove you guilty and a good way to do this is to contest the admissibility of the evidence.
Whether you're fighting charges based on the officer's judgement or charges based on a test, these are cases you can win and have a successful outcome for your DUI charge. If you need help navigating a drug DUI charge, the criminal defense team at John W. Callahan Ltd. is experienced with fighting possession and DUI charges.