Why am I being charged with both a DUI and driving with excessive blood alcohol content?

The traditional offense is “driving under the influence” of alcohol (DUI) or, in some states, “driving while intoxicated” (DWI). In recent years, however, a large majority of states have also enacted a second, so-called “per se” offense: driving with an excessive blood-alcohol concentration (BAC), which is set at 0.08% in all 50 states now. And in some cases, both offenses are charged. The defendant can even be convicted of both, but can be punished for only one.

Both laws were considered necessary because some people, notably heavy drinkers, can appear to be sober and pass field sobriety tests (FSTs) even at a high BAC level. Others on the other end of the scale may be below 0.08% BAC, but are intoxicated and their driving is adversely affected. The law wants all of them off the road.

If the case involves a refusal to submit to chemical testing, of course, only the traditional DWI/DUI offense will be charged, because officers normally are not allowed to offer opinions as to what the blood alcohol level was if no test was administered.

Case Studies: Understanding DUI and Excessive Blood Alcohol Content Charges

Case Study 1: The Sober Heavy Drinker

John, a heavy drinker, is pulled over by a police officer after driving erratically. Despite appearing sober and passing field sobriety tests, a breathalyzer test reveals his blood alcohol concentration (BAC) is above the legal limit of 0.08%.

In this case, John can be charged with both a DUI and driving with excessive BAC. The DUI charge is based on his impaired driving behavior, while the excessive BAC charge is based on the scientific measurement of his blood alcohol level.

Case Study 2: The Sober but Intoxicated Driver

Sarah, a relatively light drinker, is pulled over for swerving on the road. Although her BAC is below the legal limit of 0.08%, the officer observes clear signs of intoxication, such as slurred speech and difficulty maintaining balance during field sobriety tests. In this scenario,

Sarah can be charged with a DUI even if her BAC is not excessive. The charge is based on her impaired driving behavior and the officer’s observations of intoxication.

Case Study 3: Refusal to Submit to Testing

Mike is stopped by an officer and refuses to take a breathalyzer or blood test to determine his BAC. As a result, he is only charged with a DUI and not the offense of driving with excessive BAC. Since no test was conducted, the prosecution relies on other evidence, such as the officer’s observations and performance on field sobriety tests, to prove impairment.