Law enforcement officers in New Jersey have breath analysis equipment to detect and measure alcohol intoxication. Detecting and measuring marijuana intoxication, however, poses multiple challenges. To prosecute cases against drivers allegedly influenced by marijuana generally requires evidence, but breath tests for marijuana so far cannot reasonably measure how much a person has used or when.

Hound Labs has tried to solve this problem for law enforcement with a breath analyzer device that can detect THC, the intoxicating substance inside marijuana, within three hours of consumption. Because the first couple of hours after marijuana use causes the bulk of intoxication, the company believes that its device offers law enforcement a solution.

Simply detecting THC does not necessarily produce evidence strong enough for prosecution. No quantifiable standards for marijuana intoxication associated with measured amounts of THC have been developed. Training from the National Institutes of Health has supplied police officers with information about spotting signs of intoxication in suspects, but that determination remains subjective and outside the realm of hard evidence. A blood or urine test does not solve the problem either. THC lingers in the human body for weeks or months. Someone might test positive even though no marijuana has been consumed recently.

A person accused of drugged or drunk driving might wage a defense based on inaccurate results from a field sobriety test or faulty breath test. Legal counsel could provide a case evaluation that might aid a person who wishes to contest DUI charges. An attorney may examine what happened during the traffic stop and look for instances of police officers making mistakes when testing for intoxication. Any problems with the evidence might convince a prosecutor to drop the case or only continue with reduced charges related to other traffic offenses.