The New Jersey statute defining the offense of driving while intoxicated (DWI) allows the state to prove impairment by substances other than alcohol. At the same time, it makes it generally easier for the state to prove impairment by alcohol, partially due to the wider availability of technologies for measuring alcohol in a person’s system. The New Jersey Legislature has written the law to allow a presumption of impairment based on chemical testing for alcohol, but not other substances. A report from last year by NJ.com indicates that the rate of DWI dismissals throughout the state has increased over the past decade. It suggests that an increase in prosecutions for driving under the influence of drugs, or “drugged driving,” could be a factor. It is difficult, if not impossible, to find any single cause for a statistic like this, but it is worth noting that drugged driving is potentially more difficult for prosecutors to prove.
State law defines DWI in two ways. First, a person commits an offense if they drive “while under the influence of intoxicating liquor, narcotic, hallucinogenic or habit-producing drug.” This requires the state to prove that a defendant was impaired, or “under the influence,” through a variety of means, such as eyewitness testimony and testimony from officers trained to identify the effects of various drugs. The second type of DWI is often known as DWI per se. It only requires proof that a person drove while their blood alcohol content (BAC) was at or above 0.08 percent. State law requires anyone suspected of DWI to submit breath samples for chemical testing to determine BAC. Refusal to submit a breath sample is a separate motor vehicle offense with penalties that are almost as serious as the penalties for DWI.
Prosecutors routinely call the arresting officer or officers to testify at DWI trials. Where alcohol is allegedly involved, an officer may testify about their observations of a defendant. This may involve the odor of alcohol, or physical signs of intoxication like bloodshot or glassy eyes, slurred speech, and difficulty with balance. An officer who conducted field sobriety tests (FSTs) can offer testimony about a defendant’s performance. Even in the absence of BAC evidence, the state can offer evidence in an attempt to prove intoxication.