You can refuse to submit to a breathalyzer test, but there may be consequences. There is no simple yes or no answer. Whether someone who has been stopped for a DUI should submit to a breathalyzer test or not is a complicated question that depends on each case and the specific facts surrounding each case. With that said, in Illinois, I always prefer my DUI clients to refuse the breathalyzer test as it makes it easier to win the criminal charge of DUI at trial.
In Illinois, anyone who operates a motor vehicle on public roads is deemed to have consented to testing for alcohol and other drugs and intoxicants. In simpler terms, by driving in Illinois, you agree to chemical testing. Breathalyzer testing is the most common chemical test employed.
Under Illinois law, if you refuse to submit to a breathalyzer test your license will be suspended for one year on your first offense, and most likely you will be arrested for DUI. However, if you submit to a breathalyzer test and the test registers a result of .08 or above, you will be arrested, and if it is your first DUI, your license will be suspended for 6 months. When you submit to a breathalyzer it makes it easier for the State to prove you guilty of a DUI.
In most DUI cases, refusing to take a breathalyzer makes it harder for the state to prove you guilty of a DUI. A breathalyzer test indicating that your blood was .08 or above is a “per se” violation, which makes it easier for the state to prove that you are guilty of DUI.
A lack of a breathalyzer test does not necessarily mean that the state will be unable to prove you guilty of a DUI, but it makes the state's job harder. With a refusal of a breathalyzer, the state will not have the results of the breathalyzer to use as evidence. The state still may be able to use an admission, police officer testimony, field sobriety tests, dash cam video, or testimony of a witness to show guilt.
Aside from a breathalyzer, the results of field sobriety tests are typically the most compelling pieces of evidence that are offered by the prosecutor in DUI case.
Even field sobriety tests can be refused. This includes the standardized field sobriety tests such as the Walk-and-Turn test, the One-Leg Stand test, and HGN test; the non-standardized field sobriety tests; and the field sobriety tests for cannabis such as the Near Point Convergence test and the Romberg Balance test. Portable breath tests (PBTs) can also be refused without fear of receiving a statutory summary suspension.
Unfortunately, refusing field sobriety tests likely will result in a DUI arrest. However, refusing field sobriety tests prevent the state from using the results of the tests to prove guilt.