A Kaiser doctor gives a marijuana “medical prescription” to a young man with history of depression and PTSD. As a drugged driver he kills 1 person and injures 5 others. Is the doctor liable? The courts dismissed the case and the poor young man ended his life in suicide.
Edward Wood
Ed Wood founded DUID Victim Voices after the death of his 33-year old son Brian at the hands of two drug impaired drivers on marijuana, methamphetamine and heroin. He has a B.S. in Chemistry from Harvey Mudd College and an MBA from University of Colorado and became the founding CEO of COBE BCT. Mr. Wood has worked with victims, prosecutors, defense attorneys, judges, clinicians, drug recognition experts, law enforcement officers, toxicologists, legislators, state officials, and an international list of researchers and other specialists in his quest to increase public knowledge about DUID. Mr. Wood has four peer-reviewed publications and wrote the 2017 law requiring Colorado to begin collecting and reporting data on drug-impaired driving.
Don’t get behind the wheel of a car after ½ – 1 joint of 10 mg edible.
Marijuana’s ∆9-tetrahydrocannabinol (THC) impairs driving skills in a dose-related manner. The more one consumes, the greater the effect.
THC causes a decline in motor performance resulting in delayed reaction times and a reduced ability to stay in one’s own driving lane. Cognitive functions decline which reduces one’s ability to maintain sustained attention to driving conditions, leads to poor decision-making, impulse control and memory.[i],[ii]
The adverse effects of THC on driving safety have been proven with controlled laboratory experiments[iii], driving simulators[iv],[v] and real-world driving experiments[vi].
This myth is supported by a scene from Cheech and Chong’s movie “Up in Smoke,’ but little else. Subjects in some driving simulator studies were fairly self-aware of their impairment smoking marijuana and drove more slowly. But those users were much less successful in compensating for their impairment under emergency driving conditions. Researchers concluded that simulator studies were only able to show how marijuana users were able to drive after using the drug, rather than how they actually drove in the real world[vii].
Both the California State Patrol and the Colorado State Patrol have reported that speeding, not slow driving, was the most common reason for stopping a driver who was ultimately arrested for driving under the influence of marijuana.
Statistically this is true, but statistics are of no consolation to a parent who had lost a child due to driving under the influence of marijuana.
Multiple epidemiological studies have determined the relative risk or Odds Ratio (OR) of fatal crashes after using alcohol, marijuana, or a combination of both. Of those three conditions, the risk of a fatal crash is highest for drivers using a combination of alcohol and marijuana and the lowest for marijuana alone. The wide range of results seen from similar studies by different researchers speaks to the difficulty of conducting such studies reliably. Yet they all find that marijuana alone increases the risk of a fatal crash.
A small gauge .22 caliber bullet is about half as deadly as a medium caliber 9 mm bullet, which in turn is about half as deadly as a large .45 caliber bullet[viii]. Yet all are deadly.
This oft-quoted statement refers to a Virginia Beach study sponsored by NHTSA and summarized in 2015[ix]. The final and more detailed report was issued a year later[x]. The study failed to find a statistically significant link between car crashes and marijuana use. But a failure to find a link is not the same as finding that there is no link. It’s like your failure to find your car keys doesn’t mean that the keys no longer exist.
The Virginia Beach study failed to find a statistically significant link between car crashes and any drug or drug combination with the exception of alcohol, even though other drugs found, such as cocaine, methamphetamine, benzodiazepines, and opiates are even more impairing than marijuana[xi]. This was because NHTSA did not design the study to find statistically significant links between crash risk and drug use in the first place. Governmental incompetence is not limited to Congress. Note the following flaws in the study design[xii]:
The sample size was too small to determine statistically significant links with the low baseline prevalence of drug use in Virginia City and the lower risk posed by drugs other than alcohol.
The study site had only a 14.4% prevalence of drug use compared with a 19-22% prevalence in the rest of the nation.
The study only included drivers who volunteered to participate. It’s not clear why a drug user involved in a crash would volunteer to participate. That limitation created a downward bias to the result.
The study pool included not only the at-fault drivers in crashes, but also drivers who were innocent victims of an at-fault driver. That created a downward bias to the result.
Freeway traffic was excluded from the study, so only 15 fatal crashes were included. That created downward bias to the result.
Alcohol’s per se limit was determined by politicians based on sound scientific input. That will never happen with THC. It can’t happen because there can be no scientifically acceptable THC per se level unless the laws of chemistry and biology can change. The following points explain why that is.
All states have an alcohol DUI per se limit. Utah’s is .05 gm/dl Blood Alcohol Content (BAC), whereas it’s .08 gm/dl in all other states. The common understanding is that if a driver’s blood has a BAC of .08 or above, that proves the driver was drunk. That is not the case. A BAC of .08 or above proves that the driver was in violation of the state’s DUI law. Most state laws are written to make driving impaired by alcohol illegal. They have a separate clause stating it’s also illegal to drive with a BAC above the per se limit.
This is a dangerous myth. In fact, the combination of THC and alcohol is much more dangerous than impairment by either alcohol alone or marijuana alone. See #3 for data to support this.
Chronic users build up a tolerance to some, but not all of the effects of marijuana. After all, if they were tolerant to all of its effects, why would they keep using it? To compensate for their tolerance, chronic users consume higher quantities of a drug to obtain the desired effect. Chronic users tend to not exhibit as much motor control impairment as occasional users, and as a result will not have as much delayed reaction times or lane weaving as an occasional user[xiii]. But their executive function is still highly impaired, leading to a similar loss in judgment, memory and problem solving as occasional users[xiv].
Rather than becoming immune to THC impairment, chronic users exhibit a blunted impairment compared to occasional users[xv].
This is not true. #5 explains why there is no correlation between THC blood content and the level of impairment.
In 2017 Colorado arrested 991drivers for DUI with a THC blood content below 5 ng/ml. 74.9% were found guilty[xvi].
This is not true. Marijuana impairment tests rely upon behavioral assessments, rather than chemical assessments. Behavioral assessments are highly accurate but require time and training to administer.
Chemical tests are useful but are not required to convict someone of driving under the influence. Nationally, 24% of drivers arrested for DUI refuse chemical testing[xvii], yet they are still prosecuted and convicted.
Forensically determining impairment is akin to diagnosing an illness. A physician studies both symptoms and laboratory tests in making a diagnosis and devising a treatment plan. Police also rely upon symptoms and chemical tests to determine impairment and to prove impairment in court. Just as some disease diagnoses are straightforward and others more challenging, effectiveness of impairment assessments varies depending on the impairing substance(s), dose and symptoms. For alcohol, symptomatic assessment is easy and chemical assays are definitive. For marijuana, symptomatic assessment is much more difficult and chemical assays cannot prove or disprove impairment but can only confirm the drug responsible for the observed and documented impairment.
There are three common levels of impairment detection training provided to law enforcement officers: SFST (Standardized Field Sobriety Test), ARIDE (Advanced Roadside Impaired Driving Enforcement) and DRE (Drug Recognition Expert).
An SFST assessment can be completed within 5 minutes, whereas a DRE assessment requires an average of 45 minutes. SFST training takes about 3 days and is provided to all officers to qualify to make impaired driving arrests. ARIDE requires an additional 2 days of training. DRE requires an additional 2-3 weeks of difficult training and is not suitable for all officers.
Whereas the SFST battery of tests is well validated for detecting alcohol impairment, it is only moderately successful in detecting THC impairment. However, by adding two additional tools, finger-to-nose (FTN) and Modified Romberg Balance (MRB) to the standard three tools in SFST, officers can achieve a 96.7% reliability in detecting THC impairment[xviii].
While there is an overlap in symptoms, marijuana impairment presents different symptoms than alcohol impairment[xix].
The following symptoms are common to both alcohol and marijuana impairment:
Control loss, Inability to process changes, Loss of divided attention ability, Loss of concentration, Lane weaving, Increased reaction time
The following symptoms are either unique to or are more pronounced with alcohol impairment:
Lowered inhibitions, Faster driving, Decline in visual and auditory perceptions and processing functions
The following symptoms are either unique to or are more pronounced with marijuana impairment:
Attempted compensation, Caution in experimental settings, Can perform simple tasks effectively, but impaired higher level cognitive functions
You know people who smoke, right? Do you also know people killed by lung cancer? No? So by your logic smoking doesn’t cause lung cancer?
The problem we’re dealing with is a poor understanding of statistics. Both lung cancer and traffic deaths are fairly rare: 135,000 lung cancer fatalities and 38,000 traffic fatalities per year in the US.
The best way of looking at traffic deaths is deaths per mile driven, shown below. The number has been dropping for the last 4 decades until recently since marijuana started being legalized. It was over 3 deaths per 100 million vehicle miles traveled and was 1.13 in 2018, the last year reported.
Someone who drives 20,000 miles per year from age 16 until retirement will drive 1 million miles in a lifetime. That driver would, on average, experience a traffic fatality every 88 lifetimes (100/1.13).
A drunk driver has a much higher risk of traffic fatalities. According to the chart on #5 above, someone who consistently drives with a BAC of .08, the per se limit of most states, would increase the risk of a traffic fatality to every 9 lifetimes. No wonder it’s so hard to stop drunk driving. Drunks believe they can get away with it. And they can. Until they don’t.
A stoned driver has a lower risk of traffic fatality than a drunk driver. Depending on which estimate you choose to believe, the relative risk may range from 2 to 5. If the relative risk is on the low end of about 2, that would mean a traffic fatality every 44 lifetimes.
You’re fortunate if you haven’t met someone like Steven Ryan, Timothy Durden, Makia Milton, Mark Hendrixson, Zachary LeMaster, Unises Nuñez, Kyle Couch or John Spence who killed innocent victims while driving stoned. It’s not because driving stoned is safe, it’s just that the statistics haven’t caught up with you yet.
[i] Sewell RA, Poling J, Sofuoglu M. The Effects of Cannabis Compared with Alcohol on Driving. Am J Addict. 2009; 18(3) 185-193
[ii] Hartman RL, Huestis MA. Cannabis Effects on Driving Skills. Clin Chem 59:3 478-492 (2013)
[iii] Broyd SJ, van Hell HH, Beale C, Yücel M, Solowij N. Acute and Chronic Effects of Cannabinoids on Human Cognition – A Systematic Review. Biological Psychiatry April 1, 2016 79:557-567
[iv] Hartman RL (2013) op.cit.
[v] Hartman RL, Brown TL, Milavetz et al. Cannabis effects on driving lateral control with and without alcohol. Drug and Alcohol Dependence Sept 1 2015, 154: 25-37
[vi] Hartman RL (2013) op.cit.
[vii] Sewell RA op.cit.
[viii] Braga AA, Cook PJ. The Association of Firearm Caliber with Likelihood of Death from Gunshot Injury in Criminal Assaults. JAMA Network Open. 2018;1(3)
[ix] Compton RP, Berning A. Drug and Alcohol Crash Risk. NHTSA Traffic Safety Facts Research Note DOT HS 812 117 (2015)
[x] Lacey JH, Kelley-Baker T, Berning A et al. Drug and Alcohol Crash Risk: A Case-Control Study. Dec 2016 DOT HS 812 355 NHTSA
[xi] Bogstrand ST, Gjerde H. Which drugs are associated with highest risk for being arrested for driving under the influence? A cas-control study. Forensic Sci Int’l 240 (2014) 21-28
[xii] Wood E. Weakest In the Nation: Colorado’s DUID laws are the weakest in the nation; why and how to fix that. (2018) Amazon
[xiii] Ramaekers JG, Kauert G, Theunisse EL et al. Neurocognitive performance during acute THC intoxication in heavy and occasional cannabis users. J Psychopharmacology 23 (3) (2009) 266-277
[xiv] Ramaekers JG, van Wel JH, Spronk DB. Cannabis and tolerance: acute drug impairment as a function of cannabis use history. Scientific Reports Nature 6: 26843 (2016)
[xv] Solowij N. Peering Through the Haze of Smoked vs Vaporized Cannabis – To Vape or Not to Vape?. JAMA Open (2018); 1(7):e1848838
[xvi] Bui B, Reed J. Driving Under the Influence of Drugs and Alcohol. Colorado Department of Public Safety. June 2019
[xvii] Namuswe ES, Coleman HL, Berning A. Breath Test Refusal Rates in the United States – 2011 Update. NHTSA DOT HS 811 881 (2014)
[xviii] Hartman RL, Richman JE, Hayes CE. Drug Recognition Expert (DRE) examination characteristics of cannabis impairment. Accident Analysis and Prevention 92 (2016) 219-229
[xix] Huestis MA. Effects of cannabis with and without alcohol on driving. ACMT Seminars in Forensic Toxicology. Denver, CO, Dec 9, 2015
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