Illinois law on Driving Under the Influence (DUI) provides that “A person shall not drive or be in actual physical control of any vehicle within this State while:” [under the influence]. 625 ILCS 5/11-501 There are a number of issues involved in the quoted phrase.
One is the matter of “driving”. The police need not prove that they actually observed you driving. They must simply satisfy a jury beyond a reasonable doubt that you were driving at a time you were under the influence of alcohol. People v. Garnier, 20 Ill. App. 2d 492, 156 N.E.2d 613 (1 Dist. 1959)
This can be established by circumstantial evidence. For instance, if you the police find you in a cornfield in the middle of nowhere and your truck is ten feet away and there are no footprints in the snow, a jury might infer that you were driving. People v. Slinkard, 362 Ill. App. 3d 855, 298 Ill. Dec. 858, 841 N.E.2d 1, (1 Dist. 2006), appeal denied, 219 Ill. 2d 591(2006)
There are numerous cases on the issue of “actual physical control”. in grossly simplified form, it’s the idea of keys in the ignition, engine running. But there is no magic formula for determining whether there is actual physical control. It is a question of fact for the jury to determine. People v. Davis, 205 Ill. App. 3d 431, 150 Ill. Dec. 349, 562 N.E.2d 1152 (1 Dist. 1990)
Another question is whether you can drive drunk on wholly private property? The answer is “no” because the Illinois DUI laws apply “within the State” of Illinois. People v. Erickson, 108 Ill. App. 2d 142, 246 N.E.2d 457 (2 Dist. 1969)