Criminal Law

What Does the Prosecution Have to Prove in a DUI Case?

By John McCurley, Attorney
Read about the elements that the prosecution must prove beyond a reasonable doubt to convict you of a DUI charge at trial.

If you’re arrested and charged with driving under the influence (DUI) of alcohol or drugs, you’ll typically need to decide whether to enter into a plea bargain with the prosecution or take your case to trial. If you go to trial, you can’t be convicted unless the prosecution proves the charge beyond a reasonable doubt.

This article outlines the basic elements of a DUI (called driving while intoxicated (DWI) or operating under the influence (OUI) in some states).

(The DUI and DWI Laws section of DrivingLaws.org has extensive articles on the subject, including state-specific DUI rules and penalties.)

The Elements of a DUI

All crimes are broken up into elements—the parts of the crime that the prosecution must prove beyond a reasonable doubt before a jury or judge can find you guilty at trial. The elements of a DUI charge vary by state, but prosecutors typically need to prove the defendant was:

  • driving or operating a vehicle, and
  • under the influence or intoxicated.

In some states, the prosecution must additionally prove that the defendant was on a public roadway (as opposed to private property) while driving or operating a vehicle under the influence.

Driving or Operating a Vehicle

While most DUIs involve driving, you can get a DUI in most states without actually moving your vehicle. This is because the majority of states make it illegal not only to drive a vehicle while under the influence, but also to “operate” or “be in actual physical control” of a vehicle in such a state of impairment. The general purpose of these laws is to stop drunk driving before it begins.

The definition of when a driver is operating or in actual control of a vehicle varies by state. In most states, the judge or jury deciding your case will determine whether you were operating or in control of your vehicle by considering a number of factors, such as whether:

  • you were in the driver’s seat of your car
  • your car keys were in your possession
  • you were asleep or awake
  • your car’s motor was running
  • your car was legally parked (and where), and
  • your headlights were on.

In a handful of other states, including California, you generally can’t be convicted of a DUI unless the prosecution proves that you were actually driving your vehicle. (Mercer v. Dep't of Motor Vehicles, 53 Cal. 3d 753 (1991).)

Example: On a cold winter evening, Jane stumbles out of the saloon after finishing a large bottle of whiskey with her comrades. Jane finds her way back to her car and lounges back in the driver’s seat. She doesn’t have a blanket, so she starts her car and turns on the heater. After about 10 minutes, Sheriff Bullock happens upon her—Jane is still in the driver’s seat with her car running, but she’s fast asleep and hunched over the steering wheel.

If Jane is in California, she’s probably not guilty of DUI because she’s hasn’t driven her car. But in the majority of states it could go either way—the judge or jury will need to consider various factors (such as those listed above), and decide whether Jane was operating or in control of her car when Sheriff Bullock found her.

(Read more about the operating or driving a vehicle element.)

Under the Influence or Intoxicated

The prosecution has two options for proving that you were under the influence:

Oftentimes, the prosecution will file two DUI charges against a defendant for the same incident—a per se DUI charge and a second charge based on impairment—with the hope that one or the other will stick.

If the prosecution has a chemical test (such as a breath or blood test) showing your BAC was over the legal limit, proving a per se DUI might be more straight forward than proving impairment.

For more information on per se and impairment DUIs, see What’s the Difference Between Per Se and Impairment DUIs?

Public Roadway

The DUI laws of many states prohibit driving under the influence only on highways and roads that are open to the public. So, in these states, you generally can’t be convicted of a DUI for driving on your own private property, even if you do so while extremely intoxicated.

But there are also many states where the DUI laws don’t require proof that you were driving on a road that was accessible to the public—driving while intoxicated anywhere in the state is enough for a DUI conviction.

(For more on the public roadway issue, see Can I Get a DUI If I Was Driving on Private Property?)

Talk to an Attorney

If you’ve been arrested or charged with driving under the influence, it’s always a good idea to talk to an attorney right away. The facts of every case are different and each state has its own rules. A DUI defense attorney in your area can talk to you about the laws specific to your state and help you decide how best to proceed with your case. (For a comparison of the outcomes and costs for drivers that had an attorney versus those that didn’t, see Does a DUI Lawyer Give You a Better Outcome?)

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