Marijuana use by drivers a major cause for concern along with lack of easy, reliable test to measure impairment

Law enforcement officials in New Jersey have announced their opposition to legalization of marijuana, saying there’s currently no way for them to accurately monitor or arrest those driving under the influence of the drug.

New Jersey’s statewide association of police chiefs (NJSACOP) has released a statement officially opposing legalization of recreational marijuana in the state. The chiefs’ biggest concern is that there is not enough long-term data on record to be able to predict the impacts legalization would have on drivers and the community.

“The negative consequences related to the adoption of such legislation far outweigh any perceived benefits,” according to the press release. The organization said it would be creating a working group of law enforcement professionals to study the effects of legalization in other states and reach out to community leaders and healthcare workers to gather more information.

“Our view is that the legalization of recreational marijuana is not the answer. The NJSACOP and its membership look forward to working alongside our community stakeholders, public healthcare professionals and government leaders at all levels to find a solution, as well as to address those other issues which affect the health, welfare and quality of life of all our communities,” the statement said.

The working group will remain active until legalization is either adopted or put to rest and the association intends to present its findings on an ongoing basis.

Driving while impaired

One of the most hotly debated aspects of the legalization discussion is the effect that THC, the psychoactive component in marijuana and other cannabinoids, has on drivers. Marijuana skeptics argue that allowing recreational use would lead to more impaired individuals behind the wheel, putting both pedestrians and other drivers at risk. Proponents counter that studies have shown that drivers under the influence of cannabis often overestimate their risk factor and subsequently drive slower and more carefully, often increasing the “following distance” between themselves and other vehicles.

Sayreville police chief John Zebrowski of the NJSACOP said while the data concerning marijuana use and driving is contradictory and spotty at best, it’s still a major cause for concern among law enforcement officials.

“Pedestrian deaths have risen in states that have legalized,” Zebrowski said. Indeed, a study by the Governor’s Highway Safety Association found that the seven states (Alaska, Colorado, Maine, Massachusetts, Nevada, Oregon, Washington) and Washington, D.C., that legalized recreational use of marijuana between 2012 and 2016 reported a 16.4 percent increase in pedestrian fatalities whereas all other states — without legalization — reported a 5.8 percent decrease in pedestrian fatalities over the same period.

The authors of the study, however, were careful to note that their findings do not draw a definitive correlation between marijuana legalization and traffic fatalities; they also note that increased cell phone use may have also contributed to the number of fatalities.

“I don’t want to jump to conclusions, but there is some pattern to that,” Zebrowski said.

What’s more, a National Institutes of Health study found that despite “demonstrable neurophysiologic impairments” after consuming cannabis, “users perceive their driving under the influence as impaired and are more cautious” increasing their following distance, decreasing their speed, and refusing to overtake other drivers on the course. According to that study, “experienced smokers who drive on a set course show almost no functional impairment under the influence of marijuana.”

Judgment, coordination, reaction

Whether or not impairment is immediately visible or measurable, experts have proven that THC does have an effect on the human brain — impacting judgment, motor coordination, and reaction time. The variation in the amount of THC and the way it can affect each person differently has caused a conundrum for police officers: How do you conduct a universal, simple, and cost-effective field sobriety test for marijuana use behind the wheel?

“We need to investigate how marijuana is impairing operators of motor vehicles and what do we as law enforcement have to do to change our enforcement or look at it a different way,” Zebrowski said.

When looking at models for field-sobriety testing, the most common example is the breathalyzer that police officers use to estimate a person’s blood alcohol level by measuring the amount of alcohol present in the breath. Marijuana does not work the same way, because THC is fat-soluble instead of water-soluble like alcohol. When someone has a few drinks, alcohol saturates the lungs and blood evenly, meaning that the amount in the saliva is a good estimate of the amount in the brain.

To get an accurate readout of THC levels in the body, an individual would have to give a blood sample for analysis. Even with a set level or percentage present, there’s no widely agreed upon amount that equates to impairment for all individuals.

Hard to pin down

Colorado and Washington designated a legal limit of five nanograms of active THC in the blood before a driver could be prosecuted for driving under the influence (DUI). But regardless of the level of THC, law enforcement officers in Colorado base arrests on “observed impairment,” something that’s much harder to pin down and may not even be present in frequent smokers.

In Massachusetts, however, a recent Supreme Judicial Court ruling stated that state police officers would not be able to cite their “subjective on-scene observations or sobriety tests” such as a “walk and turn” test or “one leg stand” test to prosecute a driver as under the influence of marijuana. The ruling said there is “no scientific consensus those tests definitively prove someone is intoxicated by marijuana.”

Zebrowski said the idea of training police officers in phlebotomy — the process of drawing blood from a vein — has been discussed and it’s something that raises countless issues including high costs and possible civil rights violations for those who do not consent to a blood test.

Dr. Lewis Nelson, chairman of emergency medicine at Rutgers New Jersey Medical School, said an alternative could be to transport impaired drivers to a hospital for a blood test but it’s something he is wary of. “I don’t like the idea of bringing people to a hospital to get blood drawn,” Nelson said. “We as physicians don’t want to become an intermediary between police and patients.”

Nelson said historically physicians have had much more experience testing and observing the effects of alcohol on the body and brain, making the lack of data on marijuana worrisome.

A ‘scary’ thought

“It is scary to think that there could be a lot of people out there not at the top of their game driving a motor vehicle,” Nelson said “There are tests in development [to measure THC levels] but they are suboptimal. There is no tech currently available that could substitute for breathalyzer and I don’t know that there ever will be.”

New Jersey state police work closely with certified Drug Recognition Experts who are trained to observe the impairment caused by different types of drugs, but Nelson said he is skeptical of the science behind this training.

“I don’t know if I totally buy it,” Nelson said. “You may be able to train some people to do it, but you can’t train every officer to the same extent.”

Zebrowski said he hopes the NJSACOP will be given a seat at the table during legislative consultations and discussions to address the costs for law enforcement.