When BAC Tests Are Wrong

DUI Arrests in Chicago Often Rely on Bad Science—Don’t Let a Machine Decide Your Fate

If you were pulled over and arrested for DUI in Chicago, chances are the police relied on a breath or blood test to measure your blood alcohol concentration, or BAC. While these tests are often portrayed in court as infallible scientific proof, the truth is far murkier. Machines malfunction. Blood samples spoil. Officers skip steps. And innocent people face harsh consequences based on unreliable test results.

Under Illinois law—specifically 625 ILCS 5/11-501—it’s illegal to drive with a BAC of 0.08% or more. That level applies regardless of whether you felt drunk or not. If your BAC was over the legal limit, even slightly, you may be charged with a Class A misdemeanor DUI. But that’s just the starting point. If your BAC is exceptionally high or you have other aggravating circumstances, your misdemeanor DUI could quickly turn into a felony—a life-changing event with long-term consequences.