Driving under the influence is one of the very few crimes in which the defendant’s guilt or innocence depends almost completely on another person’s opinion. It is a troubling proposition that a court of law could impose a judgment on someone based on another’s subjective thoughts. But that is exactly what Illinois courts do for DUI. In many cases, the verdict is based on the police officer’s opinion that the defendant was intoxicated.
Basically, there are two types of DUI charges. First, a person can be charged with DUI for operating a motor vehicle with an alcohol concentration of 0.08 in his blood or breath. Second, a person can be charged with drunk driving where he is impaired, or unable to operate a motor vehicle with ordinary care. There are other types of DUI charges concerning drugs. A case can be based on intoxicating compounds (eg, prescription medication), controlled substances, cannabis, or methamphetamine. However, these types of cases appear in court far less frequently.
The two charges concerning alcohol are based on sections 11-501(a)(1) and 11-501(a)(2) of the DUI statute. This law comes from the vehicle code.
The offense of driving under the influence says that a person is guilty for having an alcohol concentration above the legal limit, or for being impaired. In cases where the defendant is charged with the legal limit, the police officer’s opinion as to the defendant’s impairment is not necessary for a conviction. This type of charge is called DUI per se. A person is guilty per se if he has an alcohol concentration of 0.08 or more in his blood or breath. It does not matter whether he is impaired.
Note that section 11-501(a)(1) does not apply to an alcohol concentration in a person’s urine. The reason is that alcohol concentration in a person’s urine will be too high to measure. The body metabolizes alcohol and absorbs some of it, but also discharges the remainder into the urine.
The kind of evidence used to prove a violation of 11-501(a)(1) would be a breathalyzer or a blood test. At the present time, there are no other types of technology used to gather evidence to prove a person is guilty of violating 11-501(a)(1).
Section 11-501(a)(2) is the most common charge for drunk driving. This is the section of the law under which the opinion controls the outcome. The reason that the police officer’s subjective opinion plays such an important role relates to the rules of evidence. It criminal case, defendant is presumed innocent. The prosecution can get a conviction only if they overcome that presumption of innocence with prove beyond a reasonable doubt. And so, the issue is reasonable doubt.
Without a breathalyzer or blood test to prove conclusively that the defendant was intoxicated, the prosecution has a problem presenting persuasive evidence. The problem inherent in all refusal cases for the prosecution is that the case basically amounts to the police officer testifying that the defendant is guilty because he seemed drunk. The police officer, without a breathalyzer, cannot tell one way or another for sure. He can only make an estimation.
Prosecutors will try to make up for this deficiency by presenting evidence of field sobriety testing. Field sobriety testing involves a series of physical tasks designed to be difficult. The thought is that someone who is impaired will fail these physical tasks.
However, despite the prosecution’s best effort to persuade the court that sobriety testing is standardized, accurate, and reliable, these cases still come down to the officer’s opinion. It is a cliché but probably true: you cannot find a person guilty when the evidence is he said, she said. If that proposition is true, it is even more likely that you cannot find a person guilty based on anyone’s subjective opinion. Generally, charges of driving under the influence based on 11-501(a)(2) should go to trial.