The testing I quoted was done on blood, not hair. You are correct - 2 data points is a line, not a trend. Other numbers to demonstrate a trend include 2013 with 47 deaths, 2014 with 66, 2015 with 88 and 2016 with 115. Yeah if you graph those numbers it is a pretty good upward trend.
72 of the 115 from 2016 (63%) were above the legal blood limit in Colorado for operating a motor vehicle while impaired.
Above the legal blood limit in Alcohol or Weed?
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During a town hall meeting, Libertarian presidential candidate Gary Johnson said “marijuana-related” traffic deaths, hospital visits and school suspensions in Colorado have “not significantly” increased since the state legalized the drug. That’s inaccurate. Statistics from various official sources show substantial increases.
But the limitations of the data make it impossible to know for sure how many of the documented incidents were directly caused by marijuana use. Unlike alcohol, for example, testing positive for marijuana doesn’t necessarily mean a person is under the influence of the drug at the time of the traffic accident.<<
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‘Marijuana-Related’ Traffic Deaths
The definition of “marijuana-related” in the Rocky Mountain High Intensity Drug Traffic Area report makes it difficult to draw conclusions from the traffic fatality data, which were drawn from the National Highway Traffic Safety Administration.
In the introduction of its report, the Rocky Mountain HIDTA states that terms such as “marijuana-related” or “tested positive for marijuana” do “not necessarily prove that marijuana was the cause of the incident.” The section on “Impaired Driving” also states that, when it comes to traffic fatalities, “marijuana-related” entails “any time marijuana shows up in the toxicology report [of drivers]. It could be marijuana only or marijuana with other drugs and/or alcohol.”
From 2009 to 2012, the “medical marijuana commercialization years,” the average yearly marijuana-related traffic deaths increased by 48 percent compared with the “early medical marijuana era” between 2006 and 2008. In the first two years after the recreational use of marijuana became legal (2013 to 2014), the average yearly marijuana-related traffic deaths increased by another 41 percent.
From 2006 to 2014 overall, marijuana-related traffic deaths increased by 154 percent, from 37 fatalities with drivers testing positive for marijuana in 2006 to 94 in 2014 — hardly an insignificant increase, as Johnson claimed. For comparison, there were 170 alcohol-related fatalities per year in Colorado between 2003 and 2012,
according to the Centers for Disease Control and Prevention.
The Rocky Mountain HIDTA report emphasizes that the proportion of marijuana-related traffic fatalities to traffic fatalities as a whole increased as well: In 2014, marijuana-related traffic fatalities made up 19.26 percent of all traffic deaths, up from 6.92 percent in 2006.
But the increase in the proportion of marijuana-related traffic deaths could merely mean that more people are using the drug — not necessarily that more people are under the influence of marijuana when involved in fatal traffic accidents.
In fact, a
January 2016 Rocky Mountain HIDTA update report, which only looked at youth and adult marijuana use, did note that 31.24 percent of college-aged adults (18 to 25) had reported using marijuana in the past month in 2013/2014, compared with 21.43 percent in 2005/2006. Likewise, 12.45 percent of adults 26-years-old and older used marijuana in the past month in 2013/2014, compared with 5.32 percent in 2005/2006.
It’s also worth noting that, according to the report, 37 percent of all drivers in 2014 who tested positive for marijuana, not just those involved in traffic fatalities, also had alcohol in their system. An additional 15 percent of all marijuana-positive drivers had other drugs in their system. And a further 15 percent of drivers had both alcohol and other drugs in their system, along with marijuana. Only 33 percent of tested drivers had only marijuana in their system.
Blood alcohol concentration of 0.08 or greater is the legal threshold for
driving while impaired in all 50 states. Blood alcohol concentration levels do correspond to a person’s intoxication level. However, marijuana and
other drugs, such as cocaine and prescription pain killers, can stay in a person’s system for a few days, so the presence of the drug alone is not necessarily an indicator of intoxication.
Other states with legalized recreational marijuana also have seen similar trends in marijuana-related traffic fatalities. In May 2016, the American Automobile Association conducted an
analysis of Washington’s marijuana-related fatalities and found that around twice as many “fatal-crash-involved drivers” had THC in their system in 2014 compared with previous years. Recreational marijuana became legal in Washington in November 2012.
Like the Rocky Mountain HIDTA’s 2015 report, the AAA report cautions that testing positive for THC doesn’t mean the driver was impaired or at fault for the crash. The AAA report added that many marijuana-positive drivers also had alcohol and other drugs in their system, “which in some cases likely contributed more significantly to the crash than did the THC.”
The National Institute on Drug Abuse
also states that “the role played by marijuana in [traffic] accidents is often unclear, because it can remain detectable in body fluids for days or even weeks after intoxication and because users frequently combine it with alcohol.” Though the NIDA adds, “The risk associated with marijuana in combination with alcohol appears to be greater than that for either drug by itself.”
A
February 2015 “Drug and Alcohol Crash Risk” study by the National Highway Traffic Safety Administration did find “a statistically significant increase” in crash risk (1.25 times) for drivers who tested positive for THC. But after the researchers controlled for age, gender, ethnicity and alcohol concentration level, increased crash risk associated with marijuana was no longer significant. This suggests these other variables “account for much of the increased risk associated … with THC,” write the study authors.
There’s also some evidence that medical marijuana laws may contribute to
decreasing traffic fatalities. One
study published in
The Journal of Law & Economics in 2013 reviewed traffic fatalities in the 19 states that had passed medical marijuana laws by 2010 and found that “legalization is associated with an 8–11 percent decrease in traffic fatalities” for the year after the laws took effect. The researchers from the University of Colorado, Denver and elsewhere also found that the decrease is more significant for alcohol-related fatalities at 13.2 percent.
To be clear, there is evidence that “marijuana significantly impairs judgment, motor coordination, and reaction time,”
according to the NIDA.
There is also no doubt that marijuana intoxication alone has played a direct role in some fatal crashes. The
Rocky Mountain HIDTA 2015 report, for example, cites a November 2014 case in which a teenager driving under the influence of only marijuana hit and killed a 16-year-old high school student. In addition to testing positive for marijuana, the teenager also showed visible signs of intoxication, such as having trouble walking in a straight line and smelling like the drug. Passengers in the car also said the driver had smoked marijuana in the car prior to driving.
Still, the question remains as to whether Colorado’s marijuana laws, or Washington’s for that matter, have directly led to surges in traffic fatalities overall. At this point, the data don’t conclusively prove that they have.<<