Timing between driving and blood draw is central to Illinois DUI proof because alcohol concentration changes with absorption, distribution, and elimination. A test drawn hours after driving cannot directly show BAC at the time of driving. The state relies on retrograde extrapolation, which requires assumptions about drinking pattern, food intake, body weight, and elimination rate. Rising-alcohol defense argues the defendant was under 0.08 while driving and above only later when tested. Delay between arrest and draw compounds uncertainty. A Chicago DUI lawyer uses the actual timeline against the state's extrapolation model, forcing the analyst to concede the assumptions and creating reasonable doubt on the BAC element.
