Study: Per Se Drugged Driving Laws Have Little Or No Impact On Traffic Deaths

  • by Paul Armentano, NORML Deputy Director January 14, 2013

    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.

    38 Responses to “Study: Per Se Drugged Driving Laws Have Little Or No Impact On Traffic Deaths”

    1. Well, Implementation of laws against drug driving seems to punish the law breakers, but its very unfortunate to see people play with their own lives and what laws are supposed to perform to prevent these deaths.

    2. Fed-Up says:

      Denis,c’mon… lighten up.It must be disturbing to know that cannabis does not effect you’re cognitive abilities and cordination in the same way alcohol does.The “reputable peers” that you have put your faith in,are not necessarily reputable, because they can easily be bought out to the highest bidder.And that has nothing to do with paranoia,just logic.

      But ill tell what is psychotic,the notion of a perfect future “drug free society” propoganda that started during the 80s.The people that are profiting on this notion,know that everything would change as far as their earnings and their corperate institutions,(if there was a drug free society),so they actualy are dependent on those “evil& misguided drug users for their livelihood.It has nothing to do with the innocent children that have their families torn apart by the “drug war,” because they need fresh new bodies to keep the dynamics going.

      Thank god people are waking up to this,but it also has to do with generational differences as well…Where talking about princeables like-honesty,values and morality.

    3. Dave Evans says:

      Having just been in a verbal disagreement can make your driving worse than the strongest pot, because even your state of mind is stronger than marijuana’s effects on perception.

    4. Dave Evans says:

      Denis, get a clue please! If you’re doing something harmful, then why should you be punished for it? Drunk driving kills people. High driving doesn’t. The law needs to reflect what happens in the real world, not some subjective shitfest.

    5. Denis says:

      Oh dear oh dear oh dear ! Where do I begin with the flaws in this ? Here are a couple :

      1) The object was to achieve X. It did not achieve Y. Therefore it does not work ? At best “Ignoratio elenchi” !
      2) The “do not drive while blindfold” law did not reduce the number of deaths whiile driving. We conclude that there is no evidence that driving while blindfolded is dangerous. What are you guys on ?

      I think that you guys have been consuming far too much of your product, and as the REPUTABLE PEER REVIEWED research shows, regular consumption has both short AND long term affects on cognitive ability.

      I think that you have just provided significant additional evidence that it should NOT be legalised !

    6. Benjamin Eaton says:

      Check out this video about pot…rethink the leaf, YES!…amazing!


    7. Very interesting research, I think it’s obvious that drinking and driving is far worse than anything involving pot.

    8. Krymsun says:

      Cannabis use is associated with only marginal increases in traffic accident risk, comparable to anti-histamines and penicillin.

      An investigator from Aalborg University and the Institute of Transport Economics in Oslo assessed the risk of road accident associated with drivers’ use of licit and illicit drugs, including amphetamines, analgesics, anti-asthmatics, anti-depressives, anti-histamines, benzodiazepines, cannabis, cocaine, opiates, penicillin and zopiclone (a sleeping pill). His study reviewed data from 66 separate studies evaluating the use of illicit or prescribed drugs on accident risk; the study found that cannabis was associated with minor, but not significantly increased odds of traffic injury (1.06) or fatal accident (1.25). By comparison, opiates (1.44), benzodiazepine tranquillizers (2.30), anti-depressants (1.32), cocaine (2.96), amphetamines (4.46), and the sleeping aid zopiclone (2.60) were all associated with a greater risk of fatal accident than cannabis. Anti-histamines (1.12) and penicillin (1.12) were associated with comparable odds to cannabis.

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