WTSC - Commission Meeting
(October 20, 2022) - Improving and Understanding Poly-Drug Information

Commissioners heard how methodology changes to improve the identification of poly-drugged driving incidents revealed significant historical overreporting of cases involving cannabis.

Here are some observations from the Thursday October 20th Washington Traffic Safety Commission (WTSC) Commission Meeting.

My top 3 takeaways:

• The commission fulfills obligations of State Highway Safety Offices like reporting traffic safety statistics in order to accept federal funding for state highway programs.
  • The WTSC Director is the Governor’s Highway Safety Representative. Though the body is chaired by Washington Governor Jay Inslee, in practice a designee of the governor leads meetings. At publication time, that was Washington State Department of Licensing (WA DOL) Director Teresa Berntsen.
    • In addition to ten Commissioners, the commission was supported by 29 employees at publication time.
  • WTSC organizes the Washington Impaired Driving Advisory Council (WIDAC) to hear from agencies and organizations working to reduce impaired driving, and assist with coordinating their work.
    • The advisory council is made up of members from seven state agencies with direct responsibility for traffic safety as well as advisory members with expertise in prevention, deterrence, treatment, rehabilitation, and program management.
    • Find out more from the WTSC impaired driving page and the ‘Target Zero’ campaign committed to ending traffic fatalities in Washington by 2030.

• Research Associate Max Roberts briefed on “Improving and Understanding Poly-Drug Information,” describing how new analysis of poly-drug traffic fatality data led to a proactive effort by commission staff to revise previous statistics, including on cannabis, aiming to be more reflective of likely impairment (audio - 12m, video, presentation).
  • Roberts said he was sharing the commission’s work “to evaluate and improve our poly-drug data among traffic fatalities” as there wasn’t an established standard. He indicated the commission had been “using the research that's available and making our best judgment as we go through this process” before offering a definition of “poly-drug positive driver” as either a “driver who is positive for alcohol and one or more other drugs as confirmed by toxicology testing, for example testing positive for alcohol and THC, or they can be a driver that is positive for two or more drugs that are not alcohol.”
  • Roberts shared statistics showing “trends in different drug and/or alcohol statuses among drivers in fatal crashes in Washington from 2008 to 2020,” mentioning that the “alcohol only and poly-drug with alcohol categories include any BAC [blood alcohol content] result greater than zero.” This indicated “drivers in fatal crashes positive for one drug only, and no alcohol, has remained relatively consistent over time” and suggested “somewhat of a decline in drivers in fatal crashes that are positive for alcohol only,” he said. “Conversely, drivers and fatal crashes that are poly-drug positive ha[d] been increasing rapidly since 2011 reaching a high of 182 drivers in 2020,” Roberts explained.
  • Staff were engaged in “reviewing positive drug results to better understand impairment and to reevaluate the prevalence of poly-drug driving in Washington,” stated Roberts. He provided a hypothetical example of “an older motorcycle rider waking up on a Sunday morning and getting ready to go for a ride.”
    • “Let's say they woke up and they had some back pain so they took a recommended dose of Tylenol, also known as acetaminophen. They have a couple cups of coffee. They take their daily prescription medication diltiazem to help with their high blood pressure. And let's also say that this person happened to smoke cannabis in the afternoon the prior day. So, on Saturday afternoon…let's say they smoke a cigarette before they go on their ride.”
    • Were the motorcycle rider killed in a traffic collision, a toxicology panel would be “conducted and the results show that this person was positive for five different substances:
      • They test positive for the acetaminophen that they took for their back pain.
      • They test positive for the caffeine in their coffee.
      • They test positive for carboxy-THC [11-Nor-9-carboxy-Δ9-tetrahydrocannabinol], which is the non-active metabolite of the THC they had smoked the day before.
      • They tested positive for their prescription medication, and they tested positive for the nicotine and its metabolite cotinine from the cigarette they smoked before the ride.”
    • Such a case would be “flagged” as a “poly-drug positive driver, and simply looking at the data one might come to the conclusion that it was drug impairment that caused the fatal crash. However, none of these substances or drugs have impairing qualities that actually contributed to the fatal crash. In fact, if we were to remove all of these non-impairing substances we would determine that…drugs and impairment were not actually involved or contributed to the fatal crash. So, we are making an effort to weed out some of these circumstances to get a better understanding of the prevalence of poly-drug positive driving.”
  • Roberts shared criteria used to determine if a substance had a potential for impairment, placing it in ‘impairing,’ ‘potentially impairing,’ and ‘non-impairing’ categories. His examples of non-impairing substances were “caffeine, acetaminophen, and non-active metabolites such as carboxy-THC.” Roberts then explained that WTSC staff were screening out poly-drug toxicological results in cases with:
    • Non-impairing drugs: acetaminophen, benzene, caffeine, carboxyhemoglobin, glucose, ibuprofen, ketones, naloxone, nicotine/cotinine, quinine, salicylate, theobromine, trimethoprim, yohimbine
    • Non-impairing/non-active metabolites:benzoylecgonine, carboxy-THC, ecgonine methyl ester, norfentanyl
      • “When a drug is metabolized in the body, it can produce either an active or a non-active metabolite” and in the “case of carboxy-THC when the body metabolizes THC. So in these circumstances, we removed four non-active metabolites only when they appear on their own and without apparent drug present.”
      • “Currently if a person is positive for a parent drug such as THC, and its metabolite such as carboxy-THC, then this is counted as two separate drugs and therefore this person is identified as poly-drug positive. But by combining parent drugs with their metabolites, we are able to determine situations where in fact only one drug had been consumed.”
      • This pairing had been determined for THC and 38 other compounds.
    • Non-impairing pharmaceuticals removed when alcohol isn't present:dextromorphan, diltiazem, glipizide, metformin, nifedipine, pseudoephedrine, norpseudoephedrine, risperidone, 9-hydroxyrisperidone, warfarin
      • “There could be a potential for interactions to occur when these drugs are paired with alcohol.”
  • Additionally, there had been a need for “identifying screening versus confirmatory results,” as the former was used to determine “presence of a certain type of drug” and if positive, a “confirmatory test to determine if a specific drug is present, and its levels in the blood or tissue.” Previously, in “some circumstances screening and confirmatory results may be present and counted as multiple drugs,” but officials had begun to “remove the screening result as we already have the…confirmatory evidence.”
  • Poly-drug fatality statistics were revised for “drug positive drivers and fatal crashes from 2015 to 2020,” covering “1,193 drivers in fatal crashes with a positive drug result. There were 125 total unique drugs, and 373 distinct combinations of drugs.” 92 cases were removed “leaving a total of 1,101 poly-drug positive cases,” he told the group, and “the number of unique drugs decreased to 106, and the distinct combinations of drugs decreased to 363.”
  • Perhaps the most dramatic change from applying this method Roberts identified was that “in the beginning data the majority, or 44%, of drug positive drivers and fatal crashes tested positive for two drugs, and only 23% tested positive for only one drug.” After reviewing the cases, officials found “this switched and the majority, nearly 67%, of drug positive drivers and fatal crashes tested positive for only one drug, and 22% tested positive for two drugs.”
  • According to Roberts, from 2015-2020 fatal crashes where alcohol was the only substance present represented “28% of drivers and fatal crashes,” followed by alcohol and THC, “representing 11% of drivers and fatal crashes.” He insisted that “trends and the message remain generally unchanged: poly-drug positive drivers remain the most prevalent group in fatal crashes, and the number of poly-drug positive drivers has been steadily increasing over time.” Roberts further noted drivers in fatal crashes “positive for alcohol increased somewhat in 2020 by eight percent” while “poly-drug positive drivers decreased by 30%, and one drug positive drivers increased by 152% but remained the least common of the three categories.”
  • Roberts made clear that WTSC would continue to apply this method to fatality statistics and planned to release “a larger report in 2023 that covers everything here and much more.” He added that officials and the public could “expect to see some changes to Washington's alcohol and drug positive driving data in the future” before repeating that the “overall trends and message remain generally unchanged.”

• Sarah Mariani, a WTSC designee representing the Washington State Health Care Authority (WA HCA), asked how much of the change in poly-drug statistics was due to reclassifying cannabis test results (audio - 1m, video).
  • Mariani, the Substance Use Disorder Prevention and Mental Health Promotion Section Manager for WA HCA Department of Behavioral Health and Recovery (DBHR), also served as president of the National Prevention Network.
    • Mariani produced Lessons Learned from Marijuana Legalization in Washington State, covering medical implementation in addition to other topics at the 2017 Prevention Summit.
    • In December 2020, she was credited as one of the people to instigate a report on health risks associated with high-concentration cannabinoid products by the WA HCA Prevention Research Subcommittee (WA HCA PRSC).
    • Mariani’s WA HCA work included assisting in conducting the Washington Young Adult Health Survey (WYAHS) and coordinating with the University of Washington Addictions, Drug, and Alcohol Institute (UW ADAI) on a draft of a “High THC policy” report due to be published by the end of 2022.
  • Mariani wondered if it was “fair to assume that the swap that happened” on statistics between “poly[-drug positive drivers] and the increase in the one drug might be mostly attributed to that THC and carb[oxy] THC?”
  • Roberts called it “absolutely a fair assumption” because “a lot of these are shrinking in size for the poly-drug in a large contribution because we're pairing those parent metabolites into single drug compounds. It doesn't make up all of them, but certainly the THC/carboxy-THC…there's a large representation there.”
    • WTSC representatives had made several claims around the increase in poly-drug positive driver fatalities since April 2018, with statistics referenced in press releases about impaired driving patrols in 2018 and 2019. Examining the 2016 data cited in the April 2018 press release revealed wide variance in the statistics over time, potentially attributable to several causes.
      • 2018 Press Release:
        • Poly-Drug: 137
        • Alcohol Only: 65
        • One Drug: 64
      • Roberts’ 2016 “before” data:
        • Poly-Drug: 172
        • Alcohol Only: 62
        • One Drug: 39
      • Roberts’ revised data:
        • Poly-Drug: 109
        • Alcohol Only: 69
        • One Drug: 88
    • The National Highway Traffic Safety Administration had various WTSC documents outlining or referencing the old poly-drug driver data, including:
      • 2018 Annual Safety Report
      • 2021 Traffic Safety Annual Report 
      • 2022 Washington Highway Safety Plan

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