New Jersey’s laws dealing with the offense of driving while intoxicated (DWI) say a great deal about impairment by alcohol, but far less about impairment by other substances. The statute makes it a motor vehicle offense to drive “while under the influence” of alcohol, with blood alcohol concentration (BAC) of 0.08 percent, or while under the influence of a “narcotic, hallucinogenic or habit-producing drug.” This last category is ill-defined, especially when compared to the vast body of law dealing with alcohol. New Jersey courts may accept testimony regarding impairment by drugs even in the absence of evidence of any specific drug in a sufficient amount to cause impairment. Understanding how New Jersey law deals with “drugged driving” is critical to mounting a defense.
State law identifies two types of DWI involving alcohol. Operating a vehicle while “under the influence of alcohol” constitutes DWI, but requires the state to prove the existence of alcohol’s “influence” over a defendant. If a defendant had BAC of 0.08 percent or more, state law presumes that they were under the influence. This is known as DWI per se. Courts have developed an extensive set of rules surrounding DWI allegedly caused by alcohol, especially when breath testing is involved.
We were part of a landmark 2008 decision by the New Jersey Supreme Court, State v. Chun, which established procedures and requirements for the admissibility of BAC evidence obtained from breath testing. It addressed the breath-testing device used by law enforcement around the state, known as the Alcotest. The state supreme court has reiterated the importance of the procedures set forth in Chun. In a 2015 decision, for example, it stated that any finding of guilt in a DWI per se case “is subject to proof of the Alcotest’s reliability.”