Can I get a DUI in my own yard, just listening to my radio and staying warm?

By sitting in your car with the key in the ignition, or even potentially with merely the key on your person or otherwise near enough to you so that you have constructive control of the vehicle, you can be charged with a DUI. Whenever there is probable cause to suspect that you were driving a vehicle and that you are intoxicated, an arrest can be made. The fact that you are on private property does not change this. While you can refuse a breathalyzer or blood test without subsequent repercussion due to the fact that the implied consent laws only apply to motorists on public highways, the DUI statute itself is very broad due to the fact that it states, "[a] person shall not drive or be in actual physical control of any vehicle" while under the influence. The statute does not state that the person must be a motorist on a public road. If a person has been drinking, then it is sound legal advice to never get inside a vehicle with the vehicle's key on your person, even if your only intent is to listen to music and stay warm. Otherwise, you're creating enough probable cause for an arrest to occur.