Source: https://www.dupage-dui-attorney.com/practice-areas/dupage-dui-defense/driving-under-the-influence-of-drugs
Timestamp: 2019-04-26 04:30:03+00:00

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One type of DUI in Illinois is driving under the influence of drugs. What is the definition of ‘drug’ as it is used under this section of the Illinois DUI Law? The short answer is that there is no statutory definition of what is – or is not-- a drug.
It is axiomatic that the drug in question must have some intoxicating effect (see People v. Vanzandt and People v. Workman) because there is no "generic" offense of "driving under the influence" ( People v. Bitterman).
"A person shall not drive or be in actual physical control of any vehicle within this State while *** under the influence of any other drug or combination of drugs to a degree that renders the person incapable of safely driving(.).
"The fact that any person charged with violating this Section is or has been legally entitled to use alcohol, other drug or drugs, or intoxicating compound or compounds, or any combination thereof, shall not constitute a defense against any charge of violating this Section."
Additionally, Illinois Pattern Jury Instruction 23.30A mirrors the above statute.
A police officer would have to be qualified by the court as an expert in order to offer an opinion regarding whether a person is under the influence of drugs. People v. Workman. Such testimony would then be circumstantial evidence that may be considered sufficient provided that the officer has the relevant skills, experience, or training to render such an opinion.
Essentially, in a case involving a charge of driving under the influence of a drug or combination of drugs, when there is no competent evidence by a qualified witness regarding the nature and effect of the drug alleged to have been ingested and the defendant has not admitted to taking the drug and being under the influence, this lack of competent testimony may create a reasonable doubt of the defendant's guilt, absent other sufficiently incriminating evidence. The following cases illustrate this principle.
In People v. Workman , a conviction for driving under the influence of drugs was reversed where the officer did not testify that he had any significant experience or expertise in detecting whether a person was driving under the influence of drugs and whether the person was influenced by a drug to such a degree that it prevented his driving safely. The officer was not knowledgeable about lorazepam, its nature, or its effects on a driver. He did not display the level of expertise necessary to sustain the charge. The only test the officer claimed to have available to him to detect whether someone was under the influence of a drug was the HGN test, a test he did not administer. The officer only became suspicious that defendant might be under the influence of something other than alcohol after he discovered the medicine bottle and after defendant had "passed" the breath test.
In People v. Jacquith, the officers were not so qualified, and, as a result, the reviewing court reversed the accused's conviction of driving under the influence of both alcohol and drugs. There, neither officer involved testified that he had previous experience with narcotics users or that he had made arrests for driving under the influence of drugs. One officer testified only vaguely that he had training at the police academy in the areas of alcohol and drugs. The officer testified that the defendant smelled of alcohol, had slurred speech, was unable to balance himself, and was unable to touch his right finger to his nose. The defendant testified that he denied consuming drugs or alcohol, he was not offered a test at the police station, and he did not admit that he was under the influence of anything. In reversing the conviction, the reviewing court concluded that the officers' testimony, which was the only testimony offered by the State on the drug issue, did not display the level of expertise necessary to sustain the conviction of driving under the influence of drugs.
In People v. Bitterman, the defendant was charged with driving under the combined influence of alcohol and drugs. The defendant admitted that he had been drinking when he was stopped by the police and then produced an envelope containing marijuana. When the officer asked the defendant if he had been smoking or was under the influence of marijuana, the defendant responded affirmatively. The officer testified regarding his observations that the defendant was under the influence of alcohol. The defendant's admissions together with the other evidence adduced at trial were found sufficient to sustain the conviction on appeal.
In People v. Vanzandt, the defendant was acquitted of DUI but was found guilty of driving under the combined influence of alcohol and drugs. At trial, the defendant presented evidence that he was diabetic and that he had taken insulin several hours previously during the evening before his arrest. He contended that his behavioral symptoms were the result of a hypoglycemic attack. Unlike the defendant in Bitterman, the defendant in Vanzandt never admitted to "being under the influence" of insulin. The reviewing court concluded that there was no evidence offered that would indicate that insulin, either by itself or in combination with alcohol, would render a person incapable of driving safely. Although the officer testified that alcohol would affect a diabetic's blood sugar level and this in turn would affect a person's coordination and ability to think clearly, the reviewing Court concluded that the officer was not qualified to give expert testimony on the complex physiological effects that alcohol produces in diabetics. Because the State otherwise failed to produce any evidence that the defendant was under the combined influence of alcohol and insulin, the reviewing Court reversed the conviction.
However, the evidence was sufficient to support a conviction for driving under the influence (DUI) of cannabis, even if results of field sobriety test were inadmissible where a police officer detected odor of cannabis on defendant's breath and in defendant's car, and defendant admitted smoking marijuana right before driving. People v. Briseno.

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