A Chicago DUI stop is challenged by proving the officer lacked reasonable articulable suspicion of a traffic or criminal violation. Illinois courts require specific, observable facts rather than a hunch. Common attack points include weaving within a lane without crossing the line, allegedly minor equipment issues, and pretextual reasons that dissolve on dashcam review. Squad video, body cam footage, and the officer's own written narrative are compared line by line. If the stop is unconstitutional, everything after it, including field sobriety results and breath readings, gets suppressed under the fruit of the poisonous tree doctrine. A Chicago DUI lawyer builds this attack from the sworn report backward.
