Study: Passage of Medical Marijuana Laws Associated With Reduced Incidences of Alcohol-Related Traffic FatalitiesAugust 13, 2013
The passage of medical cannabis laws is associated with a reduction in the public’s consumption of alcohol and with fewer incidences of alcohol-related traffic fatalities, according to data published in the Journal of Law and Economics.
Investigators at Montana State University, the University of Oregon, and the University of Colorado assessed data regarding both alcohol consumption and traffic fatality rates for the years 1990 to 2010.
Authors wrote: “Using individual-level data from the Behavioral Risk Factor Surveillance System (BRFSS) …, we find that MMLs (medical marijuana laws) are associated with decreases in the probability of [an individual] having consumed alcohol in the past month, binge drinking, and the number of drinks consumed.”
Researchers further acknowledged that this general decline in the public’s use of alcohol was likely responsible for a parallel decline in the number of alcohol-related traffic fatalities.
“Using data from FARS (federal Fatality Analysis Reporting System) for the period 1990–2010, we find that traffic fatalities fall by 8–11 percent the first full year after legalization. … Why does legalizing medical marijuana reduce traffic fatalities? Alcohol consumption appears to play a key role. The legalization of medical marijuana is associated with a 7.2 percent decrease in traffic fatalities in which there was no reported alcohol involvement, but this estimate is not statistically significant at conventional levels. In comparison, the legalization of medical marijuana is associated with a 13.2 percent decrease in fatalities in which at least one driver involved had a positive BAC level. The negative relationship between the legalization of medical marijuana and traffic fatalities involving alcohol lends support to the hypothesis that marijuana and alcohol are substitutes.”
Authors determined, “We conclude that alcohol is the likely mechanism through which the legalization of medical marijuana reduces traffic fatalities. However, this conclusion does not necessarily imply that driving under the influence of marijuana is safer than driving under the influence of alcohol. Alcohol is often consumed in restaurants and bars, while many states prohibit the use of medical marijuana in public. If marijuana consumption typically takes place at home or other private locations, then legalization could reduce traffic fatalities simply because marijuana users are less likely to drive while impaired.”
The abstract of the study, “Medical marijuana laws, traffic fatalities, and alcohol consumption,” is available free online here. NORML has several additional papers specific to the issue of cannabis and psychomotor performance available online here.
Members of the Oregon House and Senate have given final approval to two separate legislative measures, Senate Bill 40 and Senate Bill 82, to reduce penalties related to certain marijuana possession offenses.
Senate Bill 40 amends the criminal code to reclassify marijuana offenses involving the possession of over one ounce, but less than four ounces of marijuana, from a felony offense punishable by up to 10 years in prison, to a Class B misdemeanor. It also reclassifies offenses involving the possession of less than 1/4 ounce of hashish from a felony to a Class B misdemeanor. The measure also reduces the fine presently associated with civil violations involving the possession of less than one ounce of marijuana.
Senate Bill 82 eliminates the suspension of driving privileges for those cited civilly for possessing an ounce or less of marijuana.
Both bills now await action from Democrat Gov. John Kitzhaber. If signed into law, the changes will take effect immediately upon passage.
Oklahoma Gov. Mary Fallin has signed legislation, House Bill 1441, into law that criminalizes drivers from operating a motor vehicle if they have any detectable amount of THC and/or its inactive metabolites in their blood, saliva, or urine. Under such internal possession statutes, known as zero tolerance per se laws, a motorist who tests positive for the presence of such compounds is guilty per se (in fact) of a criminal traffic safety violation, regardless of whether or not there exist supporting evidence that the defendant was behaviorally impaired by such compounds.
Residual, low levels of THC may remain present in the blood of occasional consumers for several hours after past use and for several days in habitual consumers — long after any behavior-inducing effects of the substance have worn off. The inert carboxy-THC metabolite, a commonly screened for byproduct of THC, possesses a longer half-life in blood and also may be present in the urine of daily cannabis consumers for several weeks, or even months, after past use.
Oklahoma will become the 11th state to impose such a strict liability per se standard once the law takes effect on October 1, 2013. It is the third state this year to amend its traffic safety laws to include either per se thresholds or presumptive limits for cannabinoids.
Ten additional states – Arizona, Delaware, Georgia, Illinois, Indiana, Iowa, Michigan, Rhode Island, Utah, and Wisconsin – already impose zero tolerance per se thresholds for the presence of cannabinoids and/or their metabolites.
Five states impose non-zero-tolerant per se thresholds for cannabinoids in blood: Montana (5ng/ml — the new law, HB 168, signed in April, takes effect on October 1, 2013), Pennsylvania (1ng/ml), Ohio (2ng/ml), Nevada (2ng/ml) and Washington (5ng/ml).
Last month, Colorado lawmakers also approved legislation, effective as of July 1, 2013, stating that the presence of THC/blood levels above 5ng/ml “gives rise to permissible inference that the defendant was under the influence.”
However, according to the United States National Highway Transportation and Safety Administration (NHTSA): “It is difficult to establish a relationship between a person’s THC blood or plasma concentration and performance impairing effects. … It is inadvisable to try and predict effects based on blood THC concentrations alone.”
In addition, a 2013 academic review of per se drugged driving laws and their impact on road safety found “no evidence that per se drugged driving laws reduce traffic fatalities.”
A Michigan traffic safety law that prohibits the operation of a motor vehicle by persons who possess any presence of THC in their blood, regardless of whether or not they are behaviorally impaired by the substance, may not be strictly applied to state-qualified medical cannabis patients. So decided the Michigan Supreme Court on Tuesday in the case People v Koon.
In a unanimous opinion, the Court determined that legal protections extended to state-qualified patients under the Michigan Medical Marihuana Act, enacted by voters in 2008, supersede the state’s zero tolerance, internal possession law. As a result, the Court determined that state prosecutors must establish that authorized patients charged under the statute are actually impaired by their cannabis use in order to gain a DUI criminal conviction.
According to the syllabus of the Opinion:
“The MMMA [Michigan Medical Marihuana Act] does not define what it means to be ‘under the influence,’ but the phrase clearly contemplates something more than having any amount of marijuana in one’s system and requires some effect on the person. Thus, the MMMA’s protections extend to a registered patient who internally possesses marijuana while operating a vehicle unless the patient is under the influence of marijuana. The immunity from prosecution provided under the MMMA to a registered patient who drives with indications of marijuana in his or her system but is not otherwise under the influence of marijuana inescapably conflicts with MCL 257.625(8) [the state's zero tolerance per se DUI law], which prohibits a person from driving with any amount of marijuana in her or system.”
The state’s zero tolerance per se drug law remains applicable to non-patients. Under such laws, motorists are guilty per se (in fact) of a criminal traffic safety violation if they engage in the act of driving while detectable levels of certain controlled substances or, in some cases, their inert metabolites (byproducts) are present in the defendants’ blood or urine. Proof of actual impairment is not a requirement for a conviction under the law.
To date, ten states — Arizona, Delaware, Georgia, Illinois, Indiana, Iowa, Michigan, Rhode Island, Utah, and Wisconsin — have enacted legislation imposing zero tolerance per se thresholds for the presence of cannabinoids and/or their metabolites. (State-authorized medical cannabis patients in Arizona and Rhode Island are exempt from prosecution under these per se statutes unless the state can provide additional evidence of psychomotor impairment.)
Five additional states impose non-zero-tolerant per se thresholds for cannabinoids in blood: Montana (5ng/ml — law takes effect on October 1, 2013), Pennsylvania (1ng/ml), Ohio (2ng/ml), Nevada (2ng/ml) and Washington (5ng/ml). Most recently, Colorado lawmakers approved legislation stating that the presence of THC/blood levels above 5ng/ml “gives rise to permissible inference that the defendant was under the influence.” State-qualified patients in Colorado, Montana, and Nevada are not provided legal exemptions from these statutes, although legislation is presently pending in Nevada to do so.
Such caution is similarly expressed by the United States National Highway Transportation and Safety Administration, which acknowledges: “It is difficult to establish a relationship between a person’s THC blood or plasma concentration and performance impairing effects. … It is inadvisable to try and predict effects based on blood THC concentrations alone.”
A 2013 review of per se drugged driving laws and their impact on road safety found “no evidence that per se drugged driving laws reduce traffic fatalities.”
The imposition of so-called per se drugged driving laws, which create new traffic safety violations for drivers who operate a vehicle with the presence of trace amounts of certain controlled substances and/or their inert metabolites (byproducts) in their blood or urine, do not reduce incidences of traffic safety deaths.
That’s the conclusion of a just-published study by economists at the University of Colorado, Denver and Montana State University. The study is available from the Institute for the Study of Labor (IZA) in Germany as a Discussion Paper.
Since 1990, 11 states have passed so-called zero-tolerant per se drugged driving laws which make it illegal for one to drive with detectable levels of a controlled substance in his or her system. Five additional states have passed similar laws specifying non-zero limits for controlled substances or their metabolites. Fourteen (Arizona, Delaware, Georgia, Illinois, Indiana, Iowa, Michigan, Nevada, Ohio, Pennsylvania, Rhode Island, Utah, Washington, and Wisconsin) of these sixteen states impose these strict liability per se standards for cannabis. Recently, the White House Office of National Drug Control has recommended zero tolerant per se drug standards for all US states.
Using state-level data from the Fatality Analysis Reporting System (FARS) for the period 1990-2010, authors examined the relationship between the adoption of controlled substance per se thresholds and overall incidences of traffic fatalities. They found that the relationship is statistically indistinguishable from zero and concluded that there is no evidence that these limits reduced traffic deaths.
Authors reported: “Despite the fact that these laws have been touted by politicians and academics as an effective strategy for making our roadways safer, we find no evidence that they reduce traffic fatalities. … [W]e cannot determine why per se drugged driving laws do not work, and leave this issue to future researchers. However, our results clearly indicate that, as currently implemented, laws that make it illegal to drive with detectable levels of a controlled substance in the system have little to no effect on traffic fatalities.”
In November, Washington state voters approved Initiative 502, which legalizes the private use and retail sale of cannabis to adults, but also imposes a 5ng/ml THC/blood per se limit for drivers over the age of 21. In Colorado, where voters on Election Day similarly legalized cannabis, Democrat Gov. John Hickenlooper and Republican Senator Steven King are calling for the passage of nearly identical per se cannabis legislation.
NORML has consistently opposed the imposition of stand-alone per se limits for cannabinoids, arguing that the presence of THC in blood, particularly at lower levels, is an inconsistent predictor of behavioral impairment, particularly in more frequent consumers who may potentially test positive for trace, residual THC levels in their blood for periods of time exceeding any period of acute impairment.
Operation of a motor vehicle while under the influence of cannabis is already a criminal offense in all 50 states. However, in order for one to gain a criminal conviction under most state DUI laws, prosecutors must prove that a motorist recently ingested cannabis and that doing so prohibited him or her from driving safely.
Full text of the study, “Per Se Drugged Driving Laws and Traffic Fatalities,” is available online here. A separate paper previously published by the same authors reported that the passage of statewide medical marijuana laws is associated with decreased incidences of traffic fatalities.