By Alexander Nguyen

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As more states legalize marijuana, there is a growing concern that more people will drive while high.

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In addition to the newness of the legalization, testing for marijuana intoxication is notoriously difficult — a problem a California state lawmaker wants to address through the research and development of new tests. Experts, however, say that traffic crash and fatality patterns are influenced by many factors other than intoxication.

Of the four states — Washington, Oregon, Colorado and Massachusetts — that have legalized marijuana since 2012, Washington was the only state to collect extensive data on drugged driving, especially marijuana.

Data from the Washington Traffic Safety Commission shows that fatal accidents involving cannabinoids (or any form of marijuana) increased between 2013 and 2014, but then fell in 2015.

Colorado, which also saw a decrease between 2015 and 2016, only began keeping records of drugged driving since 2014 because legally, in the state, there was no difference between drunken driving and drugged driving, Sgt. Rob Madden of the Colorado State Patrol said.

While that decrease could be attributed to the novelty of legal marijuana wearing off, Madden cautioned about reading too much into the data.

“With two years of data, it’s not enough to extrapolate any reason,” Madden said. “It could be anything from greater knowledge for drivers. It could be a difference in enforcement methods, a difference in the weather pattern — a bit of a difference in everything.”

And as with drunken driving, the numbers may fluctuate from year to year, so it’s hard to establish a trend at this time, he said.

Staci Hoff, the research director at the Washington Traffic Safety Commission, agreed. She said while Washington did see an increase in the number fatal crashes involving marijuana in 2015, so did the rest the of the nation. She attributed the increase to the improving economy and more people returning to the workforce and therefore more drivers on the road.

“The silver lining of a recession is that as unemployment rates increased, traffic fatality rates decreased,” Hoff said. “In terms of the increase, it wasn’t just Washington, but that is absolutely not attributed to (the legalization of marijuana).”

Although the data on fatal crashes involving marijuana are inconclusive, and in some cases declining, there is some evidence that the opening of dispensaries has a negative effect on crash rates.

Between 2010 and 2012, the percentage of fatal crashes involving marijuana in Washington hovered around 6 percent. After marijuana became legal, that number jumped to around 12 percent between 2013 and 2015. Hoff attributed that jump to the opening of marijuana dispensaries.

“Based on the fatal crash data that is showing a trend that more and more people are not waiting (after smoking) before they get on the road,” she said.

It is illegal in Washington to consume marijuana on the shop’s premises, but it doesn’t mean that people aren’t smoking in their car (which is also illegal).

Hoff also noted that drunken drivers and drivers high on marijuana are not mutually exclusive groups, meaning that in fatal crashes, a drunken driver can also be a high driver. According to her research, drunken drivers are their own risk group, and, while adding marijuana into the mix does increase the risk but that increase is marginal, comparatively speaking.

Drivers under the influence of marijuana are twice as likely to be involved in crashes — same as drowsy drivers. Drunken drivers, meanwhile, are 200 times as likely, and distracted drivers are 10 times as likely, she said.

“A risk increase is still a concern,” she said. “But it’s important not to demonize something that we don’t know enough about yet because it could ultimately divert resources about to more important safety problems such as distracted driving and alcohol, which is still the No. 1 killer.”

Of the 1,700 or so drivers in fatal crashes that tested positive for drugs or alcohol between 2010 and 2015, only 56 drivers had only THC, the active hallucinogen in marijuana, in their system, Hoff said.

Lawmakers in California, where voters recently passed a measure to legalize marijuana, are looking for ways to combat drugged driving before the first legal recreational marijuana dispensary opens on Jan. 2, 2018.

Experts, including Hoff, said that unlike alcohol, there is no scientifically established limit on what is considered impaired. A novice marijuana user could be impaired with three nanograms of THC in their system, versus a chronic user, who could have 15 nanograms in their system and still be fine, she said.

Complicating the matter is that marijuana is a slow-releasing drug that can stay in a person’s system for weeks without affecting performance. While the effects of THC may last only a few hours, carboxy cannabinoids and hydroxy cannabinoids, which does not have a hallucinogenic effect, can stay in a person’s system for up to three weeks, according to the Centers for Disease Control and Prevention.

Testing positive for carboxy cannabinoids and hydroxy cannabinoids, the two most common indicators of drug use during a drug test, is only indicative that a person has used marijuana in the past and not indicative of current drug use, according to the CDC.

In fact, the National Transportation Safety Bureau’s Fatality Analysis Reporting System includes carboxy cannabinoids and hydroxy cannabinoids in its reporting, which skews the data on driving under the influence of marijuana, Hoff said.

That fact hasn’t stopped California Assemblyman Tom Lackey (R-Palmdale) from trying to draft legislations to combat drugged driving. He has introduced a bill to direct the California Highway Patrol to form a task force to identify the best technology to test for drugged impaired drivers, including marijuana.

California voters legalized recreational marijuana use in November 2016 but the state has until Jan. 2, 2018 to start issuing licenses for legal pot shops.

“I think what it creates is an urgency because the problem is not a new problem but because we have now created a market and created the demand for this particular substance,” Lackey said. “I think it’s imperative that we actually armed law enforcement with the tools necessary to address it effectively so that we don’t have unnecessary tragedies.”

The bill has crossed over to the California Senate but has not made it onto the floor for a vote. Two years ago, Lackey, a former CHP officer, introduced a bill that would allow police and CPH to use an “oral fluid” device to test for drugs, much in the same way that a breathalyzer is used for drunken driving. That bill died in committee.

In May, Lackey and California Police Chiefs Association demonstrated a portable saliva test that proponents say would be able to screen for marijuana and other drugs. The device is being tested in Kern, Los Angeles and Sacramento counties and Colorado.

The drug “breathalyzer” device won’t replace an officer’s judgment but is another tool for the officer to confirm impairment, Lackey said.

The CHP is also working with the Center for Medicinal Cannabis Research at the University of California, San Diego to improve the technology as well as train officers to detect drug-impaired drivers.

In the $1.8-million, two-year study, researchers are giving 180 volunteers marijuana with varying degrees of potency and testing their performance in a driving simulator as well as looking for ways to spot impairment.

“The objective is to increase awareness of impaired driving and to also provide valid information and training and skills to our officers to better identify the impaired driver regardless of what substance they may be consuming,” CHP Lt. Helena Williams said.

Currently, CHP officers receive 42 hours training to spot impaired drivers, including field sobriety test. This year, all officers and sergeants will receive 36 more hours of training on impaired driving, she said.

The medicinal use of marijuana has been legal in California since 1996, however, the CHP did not start to track drugged driver until 2014. According to Williams, the CHP did see “a substantial increase” in the number of drug-impaired drivers.

“Based off the Governors Highway Safety Association report of 2017, we are anticipating an increase (of drugged drivers) due to an increase in consumption,” she said.

This is the reason AAA opposes the legalization of recreational marijuana, said Jake Nelson, AAA’s director of Traffic Safety Advocacy and Research. There hasn’t been enough research to develop the tools to prevent and identify drug-impaired drivers, he said.

“Until we have a system in place to manage the highway safety implications of such an action we shouldn’t be legalizing a drug for fun,” Nelson said.

Does Legal Marijuana Mean More Impaired Drivers? was last modified: by

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