The term "drunk driving" is a misnomer, because a person does not have to be “drunk” to be convicted of DUI.

In Massachusetts, the law prohibits a person from operating a motor vehicle while under the influence of alcohol or drugs. Thus, the defendant does not have to be drunk. All that is required is that the person’s ability to operate safely is diminished. This is known as “diminished capacity.”

Many find it surprising that “driving” is not required to be convicted of OUI in Massachusetts. Instead, all that is required is “operation.” A person “operates” when intentionally does any act or makes use of any mechanical or electrical agency which alone or in sequence will set in motion the motive power of that vehicle.” Thus, actual driving is not required for an OUI conviction. This means being found with the car’s engine running constitutes “operation.”

It is also a misconception that it is illegal to drink and drive. For example, having one drink and driving is probably not a crime. This is because the driver is not likely to be impaired by the single drink.

Melanie’s Law makes OUI easier to prove because in addition to proving cases under the “diminished capacity” theory, prosecutors can now prove cases under the .08 theory. All that is required here is to prove that a person operated a motor vehicle, on a public way or right of access, with a blood alcohol content (BAC) of .08 or above. However, DUI lawyers are often able to challenge the BAC readings and it is entirely possible to get a not guilty verdict or dismissal, even with a breathalyzer reading which is over the legal limit.