What is “Driving Under the Influence?”

Many of those reading my blog are non-professionals seeking information about their charges. A number of inquiries ask what do the police need to prove. So, I will attempt to explain, in general terms, what the police need to prove. Note, the following is merely a general overview and should not be sued as a basis for one’s defense without consulting an attorney.

Generally, the law requires that the charging agency to prove, beyond a reasonable doubt, that the Defendant’s intake of alcohol or drugs appreciably affected their mental or physical capabilities while “operating” a vehicle. In other words, the state or city must prove:

1. The Defendant ingested a measure of alcoholic beverages or drugs, and

2. That ingestion caused the defendant’s mental or physical capabilities to be appreciably impaired, and

3. That at the time of their impairment they were “operating” a vehicle.

Ingestion of alcohol or drugs. The state must prove that you consumed some quantity of alcohol or that drugs were present in your system. Proof that you consumed alcohol is evidenced by the smell of alcohol on your breath, any admissions made by you and other extrinsic evidence such as a Horizontal Gaze Nystagmus test. Obviously, drugs are harder to prove as outward appearances may not be so obvious. But, it is important to note that drugs do not only mean illegal drugs but also include the use of prescription drugs.

Appreciable impairment. The prosecutor must prove not only that the defendant ingested alcohol and/or drugs but that consumption caused the defendant’s physical or mental capabilities to be appreciably impaired. This is evidenced by one’s demeanor - glassy eyes, slurred speech, lack of coordination, loss of memory, etc. Specific field sobriety tests such as a “walk and turn” test or a “one-legged” test is also used to examine the Defendant’s physical and mental capabilities.

“Operating” a vehicle. While the statute might state that you must be “operating” a vehicle at the time, the term in a misnomer. The vehicle need not be moving or be operated. As long as the vehicle is subject to movement, its is considered “operating” under the statute.. For example, assume you are on the side of the road, “sleeping it off” with the motor running. The courts have consistently found that this is considered operating a vehicle. And you will notice I did not use the term “motorized” or “automobile.” DUI convictions have been imposed on defendants riding bicycles. Nor does the vehicle need to be on the road. DUI conviction have been predicated upon those riding snowmobiles, boats and all terrain vehicles.

Note, the above is a discussion of DUI prosecution based upon physical evidence only. The police can also charge you alternatively with a “per se” violation if you submit to a breath, blood or urine test and the reading exceeds the minimum levels for that test. These tests, called “chemical” tests, do not require the introduction of physical evidence as they are based upon scientific testing. I will discuss this topic in a future post.