Many are watching closely as Colorado enacts a limit for how much THC, a chemical in marijuana, can be in a driver's bloodstream before they're deemed impaired.
Any marijuana in your system is enough to net you a DUI in New Jersey and Pennsylvania.
But many are now closely watching Colorado after a standardized driving limit has been established for motorists who might have used the drugs before driving. Colorado and Washington are the only states in the nation that have legalized the drug.
And while all forms of cannabis remain illegal in the commonwealth, New Jersey is one of 20 states, along with the District of Columbia, that have passed laws to allow some degree of medical marijuana use.
Attorneys in the state say a legal limit could be a helpful tool to establish a standard that's clear and objective — like the blood-alcohol limit that surrounds alcohol consumption and driving.
Colorado established a limit of 5 nanograms per milliliter of blood for tetrahydrocannabinol, or THC, the main psychoactive constituent in marijuana.
In Pennsylvania and New Jersey, officers can make an arrest if they believe a driver was impaired and specially trained drug recognition experts can be called to the scene to determine the level of impairment and what kind of substance is behind the suspected DUI. Blood or urine tests are taken if an arrest is made in order to add evidence for prosecution.
New Jersey attorney Michael Priarone said a limit, if established with sound science, could curb arbitrary enforcement.
"That would add some objective corroboration to what these drug recognition experts say," said Priarone. "Right now, it's all subjective. We need to be concerned about that."
Authorities say current tools effective
There are no major moves toward establishing a limit in New Jersey, where marijuana use is limited, according to Zachary Hosseini, spokesman for the New Jersey Division of Highway Traffic Safety.
Hosseini said impairment can be detected now through trained law enforcement, but the division would get behind whatever could make the road a safer place.
Authorities don't believe the status quo is as subjective as critics say.
The drug recognition expert training and certification program requires up to 131 hours of training and experience and is a valuable tool, authorities say.
"It's plenty effective," said Hackettstown police Sgt. Darren Tynan.
"They're very helpful in prosecution," Phillipsburg police Chief James Faulborn said, noting that an arrest made by such a highly trained officer can carry more weight in court.
If Tynan has any complaint, it's that there aren't more officers able to certify for the distinction. Right now the Hackettstown department has only one DRE-certified officer, he said, and will call upon neighboring departments for assistance on occasion. Training takes a lot of time and class space is limited.
Tynan said he hopes more sessions will open up if marijuana impairment behind the wheel becomes more of a concern in the state.
"Down the line, if states start legalizing stuff, we're going to have to figure out a way for this to be done so all the officers are able to get trained. But only time will tell," Tynan said.
New Jersey State Police Sgt. Adam Grossman said the state police, who hold some of the certification courses for DREs, are always reviewing the demand for certification and training on such programs and will adjust accordingly.
Pennsylvania doesn't need a limit, assistant DA says
Attorney Scott Wilhelm, who practices law in New Jersey and Pennsylvania, cited the relative rarity of DREs in rural parts of the state as reason why some other measurement could be helpful for everyone involved.
"I think that, without a level, it leaves it to the discretion of law enforcement, who are not always adequately trained to tell if someone is under the influence of a substance," Wilhelm said, adding that this applies even to Pennsylvania. "I'm sure (experts) can probably come up with some agreement, that there is a level at which marijuana could impair your driving," Wilhelm said.
The more widespread this limit, the easier it will be for drivers and law enforcement, he said.
But Northampton County Assistant District Attorney Joseph Lupackino said he doesn't think a limit is necessary in Pennsylvania — where all forms of marijuana use and possession remain illegal.
"Here the law is that any amount is enough to establish a DUI," he said.
Patients using the drug across the river need to recognize that it's not OK to drive impaired — be it with alcohol, prescription drugs or marijuana.
Science still developing
Colorado's law recognizes the need for more science on the subject, allowing for permissible inference in prosecuting the cases. That means the threshold isn't an automatic impairment but more of a marker for law enforcement, according to Evan Nison, executive director of New Jersey's National Organization for the Reform of Marijuana Laws, or NORML NJ.
Nison said that's a good thing since the science is relatively new and untested.
"We have a big problem with people who are driving sober but test positive for marijuana because it stays in your system 30 days," Nison said. "There is no clear answer just yet. Now larger tech companies are looking into this and examining it with their R&D capabilities."
Since impairment could affect users of marijuana differently depending on many factors, Nison said he believed the inference provided necessary flexibility. The age, size and frequency of smoking are just a few factors, he said.
"It's not black and white," Nison said. "This gives a little more flexibility and discretion to police officers and judges."
Nison noted that New Jersey's laws are a far cry from Colorado's, but its solution could make wider legalization easier.
"This is a perceived problem that many people need to get over in order to support legalization," he said. "I believe we'll be discussing legalization in the next couple of years in New Jersey. Hopefully by then we'll have more updated data on these kinds of points."