Driving while under the influence of marijuana is a controversial topic. Few people will come out and say that operating a vehicle in that mental state is an entirely safe proposition (even people who've done it regularly), but it's also wrong to simply equate it to the dangers of driving under the influence of alcohol, which is a much clearer public risk. Over the years, a number of studies have been done to determine what level of risk exists when operating a motor vehicle under the influence of marijuana. This report by the BBC is a very interesting look. In that video, a reporter rode in a car on a test track with a driver who had just used marijuana. He found that the driver did not seem impaired in any way, and actually drove somewhat better.
That's an incomplete perspective on the subject, but it's a good indication of why we need to study it scientifically. Over the years, a number of studies have been attempted, and have come to some very different conclusions. While some studies claim an increase in the risk involved with driving while stoned, a number of other studies have shown the opposite. However, there's also a noticeable trend among certain public officials to hype the danger in order to pave the way for criminal justice legislation that seems politically popular. In a roundup from a year ago, I found that a French study showing that marijuana impairment alone decreased the risk of causing a fatal crash turned up in a number of publications claiming the opposite.
Why does this matter? Because the results of some of these hyped studies, many of which do not even limit the study to the question of being under the influence, but instead to those who test positive for the substance, are being used to craft legislation that could send people to jail. In other words, we're moving towards the possibility of having laws that say that anyone who uses marijuana regularly (and will therefore test positive for it at any given time) is a criminal if they choose to drive a car, even if they're not under the influence.
The most recent study on this topic came from Canada. It claimed that drivers who tested positive for marijuana had a 29% higher risk of causing a fatal crash than motorists who did not. The main researcher for this study was Dr. Michel Bédard, the director of public health at Lakehead University in Thunder Bay, Ontario. I wrote to Dr. Bédard to get the fully study and he was kind enough to send it to me. His study was different in some ways from other studies and used a methodology that corrected for particular factors in order to eliminate the correlation between high-risk driving and drug use. I don't know if I can post it online just yet, but I will post some snippets here and discuss the problems I see with how it was done. From the abstract:
Background: Cannabis is known to have detrimental effects on human performance and may also affect driving adversely. However, studies designed to examine this issue have provided equivocal findings. We set up this study to further determine the effect of cannabis on driving.
Methods: We used a cross-sectional, case-control design with drivers aged 20-49 who were involved in a fatal crash in the United States from 1993 to 2003; drivers were included if they had been tested for the presence of cannabis and had a confirmed blood alcohol concentration of zero. Cases were drivers who had at least one potentially unsafe driving action recorded in relation to the crash (e.g., speeding); controls were drivers who had no such driving action recorded. We calculated the crude and adjusted odds ratios (ORs) of any potentially unsafe driving action in drivers who tested positive for cannabis but negative for alcohol consumption. In computing for the adjusted OR, we controlled for age, sex, and prior driving record.
Results: Five percent of drivers tested positive for cannabis. The crude OR of a potentially unsafe action was 1.39 (99% CI = 1.21-1.59) for drivers who tested positive for cannabis. Even after controlling for age, sex, and prior driving record, the presence of cannabis remained associated with a higher risk of a potentially unsafe driving action (1.29, 99% CI = 1.11-1.50).
Conclusion: Cannabis had a negative effect on driving, as would be predicted from human performance studies. This finding supports the need for interventions to decrease the prevalence of driving under the influence of cannabis, and indicates that further studies should be conducted to investigate the dose-response relationship between cannabis and safe driving.
The important thing to note here is that the study did not look at whether the cases were under the influence of marijuana at the time of the fatal crash. It counted all people who had simply tested positive for it. Bédard does reference this later and I'll dig into it more then. Another thing to note about the study is that there's no indication of whether the drivers were tested for the presence of any drugs other than alcohol or marijuana. This is another factor that will matter more as we look at the details.
Bédard makes it very clear that he's skeptical about the studies that have not shown an association between cannabis use and crashes. He writes later in the abstract:
It is possible that cannabis has minimal effects because drivers compensate for their impairment. However, it is also possible that methodological issues explain discrepancies in these findings. The concentration of THC (the active ingredient in cannabis) in drivers is typically not available nor is the amount of time since it was absorbed. Recently absorbed cannabis may affect driving adversely but this effect may wane once a longer period of time has elapsed after absorption. Because THC has a half-life of approximately seven days, many drivers who test positive for cannabis may not be impaired at the time of testing. This would lead to an underestimation of the association between cannabis and poor driving/crashes and possibly the absence of statistical significance.
Despite the large number of scenes from Cheech and Chong movies and elsewhere that have made fun of the inability to drive while stoned, many who've actually done it (and I'm one of them as you may have guessed, although it's been a few years) tend to point to what Bédard seems intent not to believe. People realize that they're impaired and they tend to drive slower and more cautiously. As I've said, it's not something I think everyone should do, but I haven't found it any more dangerous than driving while yammering away on a cell phone.
I don't have any other issues with how this study was set up. The sample set seems valid for doing the kind of comparison intended, even though it probably trims the numbers quite a bit by throwing out anyone who tested positive for any alcohol in their system. Not knowing more about how and when tests were conducted, there may be other concerns, but I don't have a reason to doubt that the collected data accurately reflects what the study claims it represents.
The methodology also took into account "Driver-related factors" (DRFs), which are driver actions coded in the data from crash reports that contributed to the initiation of the crash. This data was used to determine culpability in a fatal crash, although Bédard notes that this is not a perfect way of doing so. Bédard also uses this data to eventually correct the data for those who have a history of high risk driving. In other words, he claims that he corrected so that his data is not simply demonstrating that the kind of person who's a high risk driver is also more likely to be a marijuana user.
Of the 32,543 drivers tested, 1,647 (5%) tested positive for cannabis. Drivers who tested positive were generally younger, male, and had a poorer driving record in the past three years (see Table III; all drivers had a confirmed BAC of zero). The 10 most frequently reported DRFs are presented in Table IV. A greater proportion of drivers who tested positive for cannabis had a DRF related to speeding or erratic/reckless driving.
Again, this is the most questionable part of the study. He continues:
The findings point to cannabis as a potential risk factor in fatal crashes. Individuals who tested positive for cannabis but negative for alcohol had 29% excess risk (99% CI = 11-50) of having driven in a fashion that may have contributed to the crash, compared to drivers who tested negative for cannabis. This association was found after controlling for age, sex, and prior driving record. However, our findings likely reflect an underestimation of the actual effect of cannabis on driving. Given the long half-life of THC, it is possible that many drivers tested positive for cannabis without being impaired at the time of the crash.
That's a terrible assumption knowing what we know about driving under the influence of marijuana. Bédard concedes that he is not looking solely at people who are under the influence of marijuana, but he just assumes that the subset of those testing positive for marijuana who are actually under the influence would be even more likely to be speeding or driving recklessly. There's simply no basis for that assumption. In fact, anyone who has actually driven a car under the influence of marijuana will tell you the opposite. Some of the other DRF's he had listed might be infractions more likely under the influence of marijuana (Failure to keep in proper lane, Making improper turn, Driving on wrong side of road), but certainly not actions related to over-aggressiveness.
We also found, once more, that young males, and especially those with a bad driving record, were at greater risk of driving in an unsafe fashion, and controlled for these variables. This was important given that others have reported statistical associations between cannabis use and traffic violations, and in one study the excess risk posed by cannabis was eliminated once drinking and driving behaviour and sex were considered. Hence, we are confident that the higher risk found in drivers who tested positive for cannabis cannot be explained by aggressive driving patterns or alcohol consumption.
This is the main conclusion being reached. But by looking simply at whether one has THC in their system, it calls into question how you can even correct for aggressive driving patterns in the first place. Someone who uses marijuana at least once a week will likely always have some level of THC in their system at all times. If you're reaching the conclusion that having THC in your system causes the aggressive driving patterns, then don't you have to determine whether or not the history of aggressive driving is also a result of having THC in one's system before you correct for it? Wouldn't you have to know which of the driving histories were "THC-influenced" and which ones weren't?
In the end, I don't really think this matters. In the table showing the odds ratios for behavior that predicts a DRF leading to a fatal crash, a previous DWI is not a good predictor of that, even though the presence of THC is. This doesn't match up with what we normally see for alcohol. The presence of THC in those contributing to a DRF is certainly a statistically significant finding, but I also believe that Bédard ignored one important factor here - the use of other illicit drugs. People who use more dangerous drugs like heroin, cocaine, or meth are also more likely to be recreational marijuana users and would therefore have THC in their system. As a result, people who caused a crash under the influence of other drugs are likely skewing the results to make it appear that THC is playing a larger role than it really is in dangerous driving habits.
My main contention here is with Bédard's assumption that drivers under the influence of marijuana are affected in a way similar to alcohol, in that it increases aggressiveness behind the wheel. Marijuana and alcohol are very different drugs with very different effects. I think that we need to keep studying this subject to determine what level of risk is out there. But we need to free ourselves of those prejudices. It's easy for me to use my own history with marijuana and driving (I used to smoke marijuana before driving on long Interstate trips in order to avoid getting speeding tickets) and conclude that it's entirely safe. Driving situations often call for quick thinking actions and because of that, I don't recommend that people do it. But much like using a cell phone or eating a sandwich while driving, the risk involved is nowhere near the same level as being drunk, and there's no need to push for laws similar to our drunk-driving laws.
For the past two weeks...
Major News
- The government in Afghanistan, along with coalition forces, are set to begin eradicating the opium harvest in Helmand Province. General Peter Pace believes that Colombia's efforts to eradicate drugs are a good model for Afghanistan, even though Colombia still exports ever larger amounts of drugs and overlooks the actions of pro-government smugglers.
- Several Congressmen are still in support of using highly dangerous mycoherbicides to destroy drug harvests overseas despite the fact that even Drug Czar Walters thinks it's going too far.
- The U.S. Military has had to greatly scale back its efforts in drug interdiction as a result of the operations in Iraq and Afghanistan.
- The U.S. Supreme Court struck down a 1977 California law that allowed judges to base sentences on their own fact finding separate from a jury's recommendation. Jamie Spencer has more.
- Manuel Klausner writes in the Los Angeles Times about the senseless raids on medical marijuana dispensaries in West Hollywood, CA. Alex Coolman looks at the raids as a turning point in the battle to stop the federal government's interference in state medical marijuana laws. The LAist interviewed a medical marijuana cardholder who did not appear to have any legitimate reason for having one. Allison Margolin looks at the local media coverage.
- The Los Angeles Times writes about Felipe Calderon and his efforts to wage the war on drug traffickers in Mexico. The Drug War Chronicle provides a complete picture of the grim task that Calderon has undertaken.
- British Conservative Party leader David Cameron would support legalizing medical marijuana if shown to have medical benefits (psst, David, it does).
- A Texas parole board is recommending that Tyrone Brown, the man sentenced to life in prison for failing a drug test while on probation, should be released from jail. Governor Perry will make the final decision after his general council gives their opinion.
- Jacksonville, Florida had two more drug war victims this week. Radley Balko discusses one of the victims, Isaac Singletary, who the police conceded was an innocent man killed by officers. Scott Morgan has more. David Hunt writes in the Times-Union that the cases are causing some rethink on police tactics. Jay Elias has a great diary on it.
Opinions and Blogposts
- Newsweek looks at the pros and cons of student drug testing.
- Silja J.A. Talvi wonders if we've finally reached the breaking point in our bloated and inefficient prison system packed to the gills with drug offenders.
- Phillip Smith dismantles the Drug Czar Office's argument against licensing Afghan opium for use in legal medications. He also responds to a flippant report on a drug raid gone wrong in Indiana and finds an extremely stupid judge in Michigan.
- Mark A.R. Kleiman has an excellent lengthy critique of the drug war.
- Walter Block writes that the best way for New Orleans to solve its crime problem is to end drug prohibition. LeftIndependent looks at Philadelphia and comes to the same conclusion.
- The National Institute on Drug Abuse failed in their attempt to remove criticism of them from their wikipedia page. Jamie Spencer has a full roundup.
- Pete Guither now has a page set up to track the Alaska Bong Hits 4 Jesus case set to be tried in front of the U.S. Supreme Court. He has some initial notes in the briefs.
- LoganFerree notes that Dennis Kucinich is the only Democratic candidate who has publicly called the drug war a failure. Kucinich is likely to raise some hell chairing the subcommittee that oversees the Drug Czar's office.
- Jill Morrison writes at Feministing about prosecuting pregnant women for drug use.
- Richard Rapaport writes in the San Francisco Chronicle about how we've become confortable with the paramilitarization of law enforcement through our TV sets.
- David Borden writes about how an article out of Birmingham, England reminded him of the main reason to fight for an end to drug prohibition.
- Jamie Spencer notices that drug warriors find a lot about totalitarian leaders to admire.
- Libby Spencer writes about Mexican drug kingpins heading up north to serve their jail sentences. On the same topic, Pete Guither explains to Karen Tandy the difference between priceless and valueless.
- Tanya at Blame the Drug War posts about cleaning up discarded needles in Saskatoon.
- Loretta Nall is planning for a push to legalize medical marijuana in Alabama. She also explains to the Mobile Press-Register readership why the court dockets filled with drug indictments are a waste of resources.
- James Gierach writes that being forced to cut funding for drug law enforcement is a good thing for the city of Chicago.
- Pete Guither points to a post from Mark Kleiman about the newly discovered benefits of psilocybin (psychedelic mushrooms). Alex Coolman clarifies that this still doesn't open the door completely for a freedom of religion defense for its use.
- John Hawkins writes in support of the drug war at Human Events Online and gets his ass handed to him here, here, here, here, here, here, here, here, here, here, and here.
- Human Events Online followed that up with this crazy article overhyping the extradition of Mexican traffickers and an even more ridiculous essay from Mac Johnson. Rob at To The People takes on Johnson here. At least John Stossel makes some sense.
- As a bill to legalize marijuana is introduced in the New Hampshire legislature, one local paper thinks that the current laws regarding marijuana are working just fine. New Hampshire Blogger Toby Iselin gets a bizarre response from State Representative Delmar Burridge after urging him to vote for the bill. Burridge was quickly confronted with reality and the power of the internet.
- A Canadian ex-Pat in Amsterdam talks about how boring pot has become now that he lives in a place where it's legal.
- Kate Zabriskie writes about the academic heft behind calls for marijuana legalization.
- Steve Strommer writes about khat, Ethiopia's invasion of Somalia, and cultural integration.
- Voices posts a Daily Kos diary raising awareness of this important issue.
- Princess of Puters posts a Daily Kos diary about how the current younger generation suffers from the drug war in ways the baby boomers did not.
Regional News - U.S. and Canada
- The two Washington State residents raided for growing medical marijuana claim they were targeted for being activists. The Seattle PI agrees that the raids were unwarranted.
- Eight students at Bremerton (WA) High School were arrested on drug and weapons charges after a lengthy police investigation.
- An Idaho state senator wants to make it a felony for a pregnant woman to use any type of illegal drug while pregnant.
- Police in Santa Rosa, California are refusing a judge's order to return medical marijuana supplies to a registered patient.
- The student government at the University of California at Berkeley passed a bill to provide financial assistance for students who fall victim to the Higher Education Act's Drug Provision.
- Plumas County, California is now issuing medical marijuana cards.
- San Joaquin County, California is considering a needle exchange program to combat a Hepatitis C problem.
- A Los Angeles medical marijuana patient shot and killed a 15-year-old boy who appeared to be trying to steal his plants.
- The Drug Policy Alliance office in New Mexico has received a federal grant, courtesy of U.S Senator Jeff Bingaman, to create an anti-meth campaign aimed at students.
- The state of New Mexico has said that USAir cannot serve alcohol on flights into or out of the state.
- The Utah House Law Enforcement and Criminal Justice Committee voted to shrink the size of drug-free zones in half.
- The Montana legislature tabled a bill to expand the state's medical marijuana law.
- A local group in Topeka, KS is trying to change a state law to make it easier to arrest people for possessing drug paraphernalia.
- Oklahoma law enforcement officials have discovered that getting rid of the meth labs in their state didn't get rid of the addicts.
- Drugs have gone missing from the Bartlesville, Oklahoma police department evidence room.
- Texas Governor Rick Perry is using Department of Homeland Security grant money to stop drugs on its border - with Arkansas.
- A Texas State Senator is introducing a bill legalizing needle exchange programs.
- Texas border guards found 1,200 pounds of cocaine in a tractor-trailer arriving from Mexico.
- Officials in Texas expect to see an increase in the amount of black market cigarettes after taxes were raised by $1 per pack.
- An 18-year-old prison guard in Texarkana, TX was busted for trying to smuggle contraband into the jail.
- Three former Mississippi drug task force members were sentenced after pleading guilty to corruption charges.
- A former Iowa prison guard was sentenced to over 5 years in prison for manufacturing and selling methamphetamine.
- Minnesota lawmakers are working to introduce another medical marijuana bill.
- A Dane County (Wisconsin) Supervisor introduced a resolution to have a voter refendum on diverting first-time non-violent drug offenders from prison sentences.
- A descendant of the Straight, Inc drug treatment centers for teens called Pathway Family Center, is opening new branches in Indiana. The original Straight rehab centers had to close down after too many reports of children being tortured. Despite all this, the founder of Straight, Mel Sembler, is now the main fundraiser for Republican Presidential candidate Mitt Romney.
- The number of meth labs in Indiana continues to decrease, following the nationwide trend towards outsourcing the production to Mexico.
- Wayne County, Michigan, the county containing Detroit, saw a 20% jump in drug deaths last year, mainly due to fentanyl-laced heroin.
- Dan Harkins writes an excellent article in the Cleveland Free Times about the war on medical marijuana in Ohio.
- Florida prisoner Richard Paey is appealing his 25-year sentence for drug trafficking to the state Supreme Court. Paey is a wheelchair-bound MS sufferer who was breaking the law in order to get his pain medications.
- A Corrections Officer in Miami was arrested on bribery charges after receiving a number of gifts to allow a drug dealer to escape custody. Another prison guard in Cape Coral, Florida was busted for trying to sell weed to an undercover deputy.
- Authorities in Brevard County, Florida are predicting a busy year for drug raids.
- Atlanta Falcons quarterback Michael Vick was cleared of any wrongdoing after it was suspected that he tried to smuggle marijuana onto a flight out of Miami.
- A prison guard in Georgia was arrested for smuggling drugs and tobacco to an inmate.
- A Republican State Representative in South Carolina wants to legalize hemp farming as a way to revitalize the state's textile industry. Another South Carolina legislator, Senator Bill Mescher, is pushing for a medical marijuana bill. Amanda King can relate to his rationale.
- The Sheriff in Alamance County, North Carolina, believes his area is a major hub in drug trafficking.
- The case of David Ruttenberg, a Manassas Park, VA business owner who has been targeted in a strange case of local bureaucrats gone mad, will have his story told by the local paper. Some background in this case is here.
- In Harrisburg, PA, two people were hospitalized after using heroin mixed with quinine and possibly another substance.
- The son of Philadelphia Eagles' coach Andy Reid admitted to using heroin before he nearly killed another motorist in the Philadelphia suburbs.
- Some crack-cocaine is missing from the evidence room in the Schenectady, NY police department.
- A medical marijuana bill is in the works in Connecticut.
- A bill in Vermont to expand the current medical marijuana law has successfully moved out of the Senate committee.
- A Liberal MP in the Canadian government is criticizing the Conservative government for not doing a better job cracking down on grow houses.
- Vancouver mayor Sam Sullivan is fighting for more exemptions from Canadian federal drug laws in order to succeed at his drug law reform plans before hosting the Winter Olympics in 2010.
- A British Columbia medical marijuana supplier was arrested, leaving some patients without a supply of medication.
Regional News - International
Fun Stuff