Correction: An earlier version of this story incorrectly reported that marijuana legalization supporters in New Mexico had agreed to a blood THC level of impairment. It has been corrected below.
Copyright © 2019 Albuquerque Journal
Driving under the influence of marijuana creates a challenge for New Mexico law enforcement, where DWI is already a serious problem.
“States like Washington, Colorado don’t have the drunk driving issues that we have,” said Sen. Joseph Cervantes, D-Las Cruces, who opposes legalizing recreational marijuana.
Statistics from the national Centers for Disease Control and Prevention support the argument that New Mexico has a bigger problem than those states. In 2016, New Mexico’s drunken driving death rate was 4.8 per 100,000 population. The rate in Washington was 2.1, in Oregon 2.2 and Colorado 2.5 per 100,000 population.
Cervantes’ concerns are echoed by Republicans including Rep. Bill Rehm of Albuquerque, who oppose recreational marijuana legalization because, he says, it would increase the number of dangerous drivers on the road.
“Isn’t the problem already bad enough?” he asked during an interview.
Marijuana use can affect brain areas that regulate balance, posture and coordination and can slow down reaction time. Alcohol also affects coordination and reaction time but also reduces attention span, vision and judgment.
Unlike alcohol, how much marijuana is needed to make a person too impaired to drive is still a subject of disagreement in the scientific community. In New Mexico, for example, a blood alcohol level of 0.08 is the level of presumed intoxication.
The science behind a similar standard for marijuana is much murkier – and there is no marijuana equivalent of a Breathalyzer test that suspected drunken drivers are required to take under the state’s Informed Consent Law.
The only way to test for THC levels is through a blood test – which would require a search warrant that state law doesn’t allow in a typical impaired driving case.
Even then, the federal National Institute on Drug Abuse says the role “played by marijuana in (vehicle) crashes is often unclear because it can be detected in body fluids for days or even weeks after intoxication and because people frequently combine it with alcohol.”
Law enforcement agencies in Colorado and other states say crashes have increased because of people driving under the influence of marijuana and other drugs. How much of an increase is being studied. And supporters question how much of that increase is actually attributable to marijuana.
Arrests for drugged driving have also increased in states where recreational marijuana has been legalized. But how much of that increase is due to law enforcement agencies’ increased training and enforcement after legalization?
An Albuquerque police spokesman didn’t respond to requests for information about how many drug recognition experts APD had.
Some states have set standards for the amount of THC found in the blood test of a suspected drugged driver – similar to New Mexico’s 0.08 presumed intoxication standard for alcohol.
Those states initially required drivers to submit to blood tests if they are suspected of driving while on drugs to keep a driver’s license.
But the U.S. Supreme Court ruled in 2016 that states could not compel suspected drunken drivers to take a blood test without a search warrant because the procedure was invasive and blood evidence contains a person’s genetic material – unlike a breath test for alcohol.
A year later, the state Supreme Court reiterated that and clarified that in New Mexico, police officers can obtain search warrants only in felony investigations – DWI is a misdemeanor – or if the traffic incident involves great bodily harm.
Although officers can administer a Breathalyzer in a suspected drunken driving case, if the issue is drugged driving, they have to rely on specially trained officers, called drug recognition experts, who can administer field tests to determine whether someone is under the influence.
“There are not enough State Police officers trained as drug recognition experts,” said Jeremy Vaughan, president of the State Police Officers Association.
To become a drug recognition expert, an officer must have completed and passed the 24-hour National Highway and Transportation Safety Association DWI Detection and Standardized Field Sobriety Training course in all tasks. The officer should have experience in detecting and arresting DWIs to include testimony in court.
The officer must have completed the 16-hour NHTSA Advanced Roadside Impaired Driving Enforcement course.
And that’s before they take the drug recognition expert course.
Rehm, a retired Bernalillo County sheriff’s captain, said, “This gets expensive. Even more so for smaller departments.”
There is no marijuana breath test to give drivers suspected of being high.
“I know states are looking at various technological advances that would help determine if someone is under the influence while driving,” said Bernalillo County District Attorney Raúl Torrez. “But there haven’t been any significant breakthroughs.”
That leaves law enforcement with two alternatives – a blood test or a field sobriety test administered by a police officer trained as a drug recognition expert.
Emily Kaltenbach, state director of the Drug Policy Alliance, said legalization supporters in New Mexico have not agreed to a blood THC level of impairment of 5 nanograms per milliliter – the standard adopted by several states as presumptive evidence of drugged driving.
Some European countries have set the THC blood level for impairment at 2 nanograms per milliliter. But they also have set blood alcohol levels for drunken driving at 0.05, compared with states in the U.S. that have it set at 0.08.
Some countries make a drugged driving exception for people using medical cannabis because the regular use of marijuana can result in low levels of THC in the blood for long periods without any signs of impairment.
But Kaltenbach said the science may not support whether THC blood levels have anything to do with a driver’s level of impairment.
According to several government reports, smoking marijuana leads to a rapid high that can last a few hours, and THC concentrations in the bloodstream fall rapidly within a half-hour of smoking it.
But if someone eats a cannabis oil-laced candy, the THC gets into the bloodstream more slowly – and the concentrations can last longer.
“This is all pretty complicated,” Vaughan said. “But we don’t want to be in a position of playing catch-up. It takes money, and we’re asking the Legislature to prepare for that.”