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Arizona Supreme Court Makes It Harder to Convict Unimpaired Pot Smokers
of Driving Under the Influence
Jacob Sullum | Apr. 23, 2014 4:58 pm
Yesterday the Arizona Supreme Court ruled that people whose blood
contains a secondary, inactive byproduct of marijuana can drive without
violating state law. That means cannabis consumers are less likely to be
charged with driving under the influence of a drug (DUID) when they are
not actually impaired.
Arizona, one of seven states with a "zero tolerance" DUID law, forbids
driving by anyone whose body contains any amount of an illegal drug "or
its metabolite." The question for the Arizona Supreme Court was whether
"its metabolite" includes carboxy-THC, which is not psychoactive and can
be detected up to a month after consumption of cannabis. The court
deemed the phrase ambiguous, since it could be understood as referring
only to hydroxy-THC, a primary metabolite that is psychoactive. In light
of the legislature's aim to prevent impaired driving, the court said,
that interpretation makes more sense, especially since the alternative,
including any chemical trace left by the metabolism of an illegal drug,
would lead to "absurd results":
This interpretation would create criminal liability regardless of
how long the metabolite remains in the driver's system or whether it has
any impairing effect. For example, at oral argument the State
acknowledged that, under its reading of the statute, if a metabolite
could be detected five years after ingesting a proscribed drug, a driver
who tested positive for trace elements of a non-impairing substance
could be prosecuted.
The broader interpretation would therefore "criminalize otherwise legal
conduct": medical use of cannabis permitted by state law. "Because
Carboxy-THC can remain in the body for as many as twenty-eight to thirty
days after ingestion," the court noted, "the State's position suggests
that a medical-marijuana user could face prosecution for driving any
time nearly a month after they had legally ingested marijuana."
The court noted that a broad reading of "its metabolite" could have
absurd results when applied to other drugs as well:
This interpretation would allow the prosecution of an individual
who drives after ingesting a legal substance that shares a non-impairing
metabolite with a proscribed substance. For example, serotonin, a legal
substance, and the proscribed drug bufotenine [a psychedelic found in
fly agaric mushrooms and the skin of certain toads] share a common
metabolite, 5-hydroxindoleactic acid ("5-HIAA")....Under the State's
interpretation of "metabolite," it could prosecute a driver who had
5-HIAA in his or her system after ingesting a legal serotonin supplement
or, for that matter, whose blood contains 5-HIAA as a byproduct of
naturally produced serotonin.
This decision is reminiscent of a 2010 ruling in which the Michigan
Supreme Court narrowly interpreted that state's zero-tolerance DUID law,
which says a person may not drive "if the person has in his or her body
any amount of a controlled substance listed in schedule 1," which
includes marijuana, THC, and "their derivatives." The Michigan Supreme
Court said carboxy-THC does not count as a "derivative."
Despite these rulings, it is still possible for unimpaired marijuana
consumers to be convicted of DUID in Arizona and Michigan, since any
amount of active THC in the blood will suffice. In fact, such
convictions are possible even under less strict per se standards, such
as Washington's new rule equating five nanograms of THC per milliliter
of blood with impairment, which makes it illegal for many medical users
to drive even when they are perfectly capable of doing so safely. Given
variation in the way people respond to psychoactive substances
(including alcohol) , per se standards are bound to unfairly tar some
people as public menaces That is a good reason to require additional
proof of impairment—unless you are using road safety as an excuse to
punish people for consuming politically incorrect drugs, in which case
per se (and ideally zero tolerance) is the way to go.
[Thanks to Marc Sandhaus and Richard Cowan for the tip.]
Jacob Sullum is a senior editor at Reason magazine and a nationally
syndicated columnist.
of Driving Under the Influence
Jacob Sullum | Apr. 23, 2014 4:58 pm
Yesterday the Arizona Supreme Court ruled that people whose blood
contains a secondary, inactive byproduct of marijuana can drive without
violating state law. That means cannabis consumers are less likely to be
charged with driving under the influence of a drug (DUID) when they are
not actually impaired.
Arizona, one of seven states with a "zero tolerance" DUID law, forbids
driving by anyone whose body contains any amount of an illegal drug "or
its metabolite." The question for the Arizona Supreme Court was whether
"its metabolite" includes carboxy-THC, which is not psychoactive and can
be detected up to a month after consumption of cannabis. The court
deemed the phrase ambiguous, since it could be understood as referring
only to hydroxy-THC, a primary metabolite that is psychoactive. In light
of the legislature's aim to prevent impaired driving, the court said,
that interpretation makes more sense, especially since the alternative,
including any chemical trace left by the metabolism of an illegal drug,
would lead to "absurd results":
This interpretation would create criminal liability regardless of
how long the metabolite remains in the driver's system or whether it has
any impairing effect. For example, at oral argument the State
acknowledged that, under its reading of the statute, if a metabolite
could be detected five years after ingesting a proscribed drug, a driver
who tested positive for trace elements of a non-impairing substance
could be prosecuted.
The broader interpretation would therefore "criminalize otherwise legal
conduct": medical use of cannabis permitted by state law. "Because
Carboxy-THC can remain in the body for as many as twenty-eight to thirty
days after ingestion," the court noted, "the State's position suggests
that a medical-marijuana user could face prosecution for driving any
time nearly a month after they had legally ingested marijuana."
The court noted that a broad reading of "its metabolite" could have
absurd results when applied to other drugs as well:
This interpretation would allow the prosecution of an individual
who drives after ingesting a legal substance that shares a non-impairing
metabolite with a proscribed substance. For example, serotonin, a legal
substance, and the proscribed drug bufotenine [a psychedelic found in
fly agaric mushrooms and the skin of certain toads] share a common
metabolite, 5-hydroxindoleactic acid ("5-HIAA")....Under the State's
interpretation of "metabolite," it could prosecute a driver who had
5-HIAA in his or her system after ingesting a legal serotonin supplement
or, for that matter, whose blood contains 5-HIAA as a byproduct of
naturally produced serotonin.
This decision is reminiscent of a 2010 ruling in which the Michigan
Supreme Court narrowly interpreted that state's zero-tolerance DUID law,
which says a person may not drive "if the person has in his or her body
any amount of a controlled substance listed in schedule 1," which
includes marijuana, THC, and "their derivatives." The Michigan Supreme
Court said carboxy-THC does not count as a "derivative."
Despite these rulings, it is still possible for unimpaired marijuana
consumers to be convicted of DUID in Arizona and Michigan, since any
amount of active THC in the blood will suffice. In fact, such
convictions are possible even under less strict per se standards, such
as Washington's new rule equating five nanograms of THC per milliliter
of blood with impairment, which makes it illegal for many medical users
to drive even when they are perfectly capable of doing so safely. Given
variation in the way people respond to psychoactive substances
(including alcohol) , per se standards are bound to unfairly tar some
people as public menaces That is a good reason to require additional
proof of impairment—unless you are using road safety as an excuse to
punish people for consuming politically incorrect drugs, in which case
per se (and ideally zero tolerance) is the way to go.
[Thanks to Marc Sandhaus and Richard Cowan for the tip.]
Jacob Sullum is a senior editor at Reason magazine and a nationally
syndicated columnist.
