According to recent media reports, the number of convictions for driving while intoxicated (DWI) in New Jersey is decreasing, at least with regard to cases involving alcohol. The decline reportedly might be due to an increase in DWI cases involving marijuana and other controlled substances. New Jersey law provides no per se standard for impairment by marijuana or other drugs that is comparable to the standard for alcohol. A bill currently pending in the New Jersey Assembly, A2776, would establish a per se standard for marijuana in DWI cases. This bill, if enacted, would probably present both benefits and drawbacks for New Jersey DWI defendants.
New Jersey law creates a presumption of impairment if a defendant’s blood alcohol content (BAC) is at least 0.08 percent. This is often known as DWI per se. Since no similar standard exists for marijuana and other drugs, prosecutors must rely on testimony from police officers who have received training as “drug recognition experts” (DREs). Typically, a DRE-certified officer observes a defendant during or shortly after their arrest, and then forms an opinion of which substance(s) they took. The use of DRE testimony in court presents problems for defendants, given the wide gulf that often exists between the questionable scientific basis of their training and the weight that courts often give to police officers’ testimony.
Tests for marijuana look for specific compounds in the blood. Delta 9-tetrahydrocannabinol (THC) is the active component of marijuana, but it can dissipate in the bloodstream within a few hours. As the body metabolizes THC, it produces a form of carboxylic acid known as delta 9-carboxy-THC (THC-COOH) as a metabolite. The presence of THC-COOH can determine if someone has recently used marijuana, but it is a less accurate method of establishing actual impairment.