Transport (Papers)

Legalizing recreational marijuana use in Colorado, Oregon and Washington has resulted in collision claim frequencies that are about three percent higher overall than would have been expected without legalization, a new insurance report has found.

The Highway Loss Data Institute (HLDI) report says that more drivers admit to using marijuana, and the substance is showing up more frequently among people involved in crashes.

The HLDI report authors note that although there is evidence from simulator and on-road studies that marijuana can degrade some aspects of driving performance, researchers haven’t been able to definitively connect marijuana use with more frequent real-world crashes.

Some studies have found that using the drug could more than double crash risk, while others, including a large-scale federal case-control study, have failed to find a link between marijuana use and crashes. Studies on the effects of legalizing marijuana for medical use also have been inconclusive.

Colorado and Washington were the first states to legalize recreational marijuana for adults age 21 and older with voter approval in November 2012. Retail sales began in January 2014 in Colorado and in July 2014 in Washington. Oregon voters approved legalized recreational marijuana in November 2014, and sales started in October 2015.

HLDI conducted a combined analysis using neighbouring states as additional controls to examine the collision claims experience of Colorado, Oregon and Washington before and after law changes. Control states included Idaho, Montana, Nevada, Utah and Wyoming, plus Colorado, Oregon and Washington prior to legalization of recreational use.

During the study period, Nevada and Montana permitted medical use of marijuana, Wyoming and Utah allowed only limited use for medical purposes, and Idaho didn’t permit any use. Oregon and Washington authorized medical marijuana use in 1998, and Colorado authorized it in 2000.

HLDI also looked at loss results for each state individually compared with loss results for adjacent states without legalized recreational marijuana use prior to November 2016.  “The combined-state analysis shows that the first three states to legalize recreational marijuana have experienced more crashes,” says Matt Moore, senior vice president of HLDI. “The individual state analyses suggest that the size of the effect varies by state.”

Colorado saw the biggest estimated increase in claim frequency compared with its control states. After retail marijuana sales began in Colorado, the increase in collision claim frequency was 14 percent higher than in nearby Nebraska, Utah and Wyoming. Washington’s estimated increase in claim frequency was 6 percent higher than in Montana and Idaho, and Oregon’s estimated increase in claim frequency was 4 percent higher than in Idaho, Montana and Nevada.

“The combined effect for the three states was smaller but still significant at 3 percent,” Moore says. “The combined analysis uses a bigger control group and is a good representation of the effect of marijuana legalization overall. The single-state analyses show how the effect differs by state.”

Each of the individual state analyses also showed that the estimated effect of legalizing recreational use of marijuana varies depending on the comparison state examined. For example, results for Colorado vary from a 3 percent increase in claim frequency when compared with Wyoming to a 21 percent increase when compared with Utah.

Data spanned collision claims filed between January 2012 and October 2016 for 1981 to 2017 model vehicles. Analysts controlled for differences in the rated driver population, insured vehicle fleet, the mix of urban versus rural exposure, unemployment, weather and seasonality.

Collision claims are the most frequent kind of claims insurers receive. Collision coverage insures against physical damage to a driver’s vehicle in a crash with an object or other vehicle, generally when the driver is at fault. Collision claim frequency is the number of collision claims divided by the number of insured vehicle years.

HLDI said it will continue to examine insurance claims in states that allow recreational use of marijuana. Meanwhile, IIHS has begun a large-scale case-control study in Oregon to assess how legalized marijuana use may be changing the risk of crashes with injuries. Preliminary results are expected in 2020.

In addition to Colorado, Oregon and Washington, five other states and Washington, D.C., have legalized marijuana for all uses, and 21 states have comprehensive medical marijuana programs as of June. An additional 17 states permit limited access for medical use. Marijuana is still an illegal controlled substance under federal law.

“Worry that legalized marijuana is increasing crash rates isn’t misplaced,” says David Zuby, executive vice president and chief research officer of the Insurance Institute for Highway Safety. “HLDI’s findings on the early experience of Colorado, Oregon and Washington should give other states eyeing legalization pause.”

The Highway Loss Data Institute (HLDI) conducts studies of insurance data on vehicle losses and by publishes insurance loss results by vehicle make and model. Its sister research organization, the Insurance Institute for Highway Safety (IIHS), is focused reducing the losses from motor vehicle crashes. Both organizations are wholly supported by auto insurers and insurance associations.

State Efforts

The Governors Highway Safety Association (GHSA) has urged states to equip themselves with the latest research and recommends that they increase drug testing, bolster laboratory resources, track alcohol (DUI) and drugged (DUID) related driving data separately in state records, use surveys to gauge public attitudes, and evaluate the effects of any law or program changes.

The group has issued a guide, Drug Impaired Driving: A Guide for States, for states. Chief among the report’s recommendations is increased training for law enforcement officers to help them identify and arrest drugged drivers.

“As states across the country continue to struggle with drug-impaired driving, it’s critical that we help them understand the current landscape and provide examples of best practices so they can craft the most effective countermeasures,” said Jonathan Adkins, executive director of GHSA.

GHSA said this year five states are getting grants totalling $100,000 to implement Advanced Roadside Impaired Driving Enforcement (ARIDE) training and Drug Recognition Expert (DRE) programs. The states are Illinois, Montana, Washington, West Virginia and Wisconsin.

Related Research

The HLDI authors cite other research into drugs and driving including a 2016 IIHS survey that found that drivers in Colorado, Oregon and Washington were more likely to view marijuana as a highway safety problem than drivers in states without legalized use (Drivers say alcohol is bigger threat than pot).

A 2016 Columbia University study looked at traffic fatalities in 19 states before and after they enacted legalized medical marijuana laws. On average there was an 11 percent reduction in fatality rates, although the results varied across states. Seven states saw a reduction, while two had an increase, and the other 10 didn’t change.

Researchers using the National Advanced Driving Simulator found that while drivers under the influence of marijuana had trouble maintaining constant lane position, they drove more slowly and with more headway than drivers not under the influence.

About 1 in 5 weekend night-time drivers tested positive for at least one legal or illegal drug in the 2013-14 National Roadside Survey of Alcohol and Drug Use by Drivers conducted by the National Highway Traffic Safety Administration (NHTSA) (More drivers use marijuana, but link to crashes is murky).

A 2016 AAA Foundation study in Washington since legalization estimated that the prevalence of drivers in fatal crashes with marijuana in their blood roughly doubled from 8.3 percent in 2013 to 17 percent in 2014.

The National Highway and Traffic Safety Administration (NHTSA) examined the crash risk associated with driver drug use and found that drivers who tested positive for marijuana were overrepresented in the crash-involved population (More drivers use marijuana, but link to crashes is murky). However, they found no link between marijuana use and driver crash risk. The study, published in 2016, included 2011-12 data on police-reported crashes in Virginia Beach, Virginia, where it is illegal to use marijuana.

Source:  http://www.insurancejournal.com/news/

Even in a culture that puts safety above all else, pilots aren’t properly educated about the potential dangers of common drugs such as antihistamines and sleeping pills. That’s the conclusion from a new National Transportation Safety Board report on rising drug use among aviators, which largely mirrors trends of greater use of prescription, over-the-counter, and illicit drugs by Americans in general.

About 40 percent of the 6,667 pilots killed in accidents since 1990 had prescription, over-the-counter, or illicit drugs in their bodies, according to a study of nearly 6,600 accidents from 1990 to 2012. Over-the-counter antihistamines such as Benadryl and Claritin were the most common. Antihistamine use rose to almost 10 percent between 2008 and 2012, up from 5.6 percent in the 1990s.

The vast majority of those killed in the period of the study—96 percent—were general aviation pilots typically flying small, one-engine planes; less than 1 percent of incidents involved major airlines. The study focused on evidence of drug use, not on whether the effects of the drug led to impairment while flying. Alcohol was not included in the study because toxicology screenings often detect ethanol the body creates naturally after death.

Use of illicit drugs such as marijuana and cocaine increased to almost 4 percent in the 2008-12 span, up from 2.3 percent in the 1990s. Most of the illicit drugs in the study resulted from greater use of marijuana among the pilots who died, the agency said.

The NTSB, which recommends safety improvements, called on the Federal Aviation Administration to better educate pilots about the potential dangers of some common drugs and develop a policy on marijuana use by pilots. Colorado and Washington have legalized marijuana for adult use, and almost two dozen other states allow marijuana for medical uses. More states are also likely to vote on legalizing recreational and medical marijuana use.

Dr. Mary Pat McKay, the NTSB’s chief medical officer, said more research is needed to determine how drugs can interact with each other and lead to pilot impairment. Sleep aids and pain medications, for example, can hurt pilot performance and yet there aren’t guidelines on how pilots might safely use those drugs.

Source: www.businessweek.com  10th Sept. 2014

The proportion of marijuana-positive drivers involved in fatal motor vehicle crashes in Colorado has increased dramatically since the commercialization of medical marijuana in the middle of 2009, according to a study. The study raises important concerns about the increase in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive since the commercialization of medical marijuana in Colorado, particularly in comparison to the 34 non-medical marijuana states. 

ShapeThe proportion of marijuana-positive drivers involved in fatal motor vehicle crashes in Colorado has increased dramatically since the commercialization of medical marijuana in the middle of 2009, according to a study by University of Colorado School of Medicine researchers.

With data from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System covering 1994 to 2011, the researchers analyzed fatal motor vehicle crashes in Colorado and in the 34 states that did not have medical marijuana laws, comparing changes over time in the proportion of drivers who were marijuana-positive and alcohol-impaired.

 The researchers found that fatal motor vehicle crashes in Colorado involving at least one driver who tested positive for marijuana accounted for 4.5 percent in the first six months of 1994; this percentage increased to 10 percent in the last six months of 2011. They reported that Colorado underwent a significant increase in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive after the commercialization of medical marijuana in the middle of 2009. The increase in Colorado was significantly greater compared to the 34 non-medical marijuana states from mid-2009 to 2011. The researchers also reported no significant changes over time in the proportion of drivers in a fatal motor vehicle crash who were alcohol-impaired within Colorado and comparing Colorado to the 34 non-medical marijuana states.

Stacy Salomonsen-Sautel, Ph.D, who was a postdoctoral fellow in the Department of Pharmacology, is the lead author of the study, which is available online in the journal Drug and Alcohol Dependence. Christian Hopfer, MD, associate professor of psychiatry, is the senior author. 

Salomonsen-Sautel said the study raises important concerns about the increase in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive since the commercialization of medical marijuana in Colorado, particularly in comparison to the 34 non-medical marijuana states. While the study does not determine cause and effect relationships, such as whether marijuana-positive drivers caused or contributed to the fatal crashes, it indicates a need for better education and prevention programs to curb impaired driving.

Source:. Trends in fatal motor vehicle crashes before and after marijuana commercialization in Colorado. Drug and Alcohol Dependence, 2014; DOI: 10.1016/j.drugalcdep.2014.04.008

The threat to public safety on the roadways posed by marijuana-impaired driving has been pushed to the top of nation’s agenda by the legalization of marijuana in Colorado and Washington as well as by the legalization of “medical” marijuana in 18 states and the District of Columbia. Marijuana has significant impairing psychological and physiological effects on driving. Marijuana use by drivers puts everyone at risk on our nation’s roadways; research shows that marijuana is a major cause of impaired driving and serious and fatal injury crashes.

To address marijuana-impaired driving, there has been an interest in identifying an impairment standard for marijuana that is the equivalent to the 0.08 g/dl Blood Alcohol Concentration (BAC) now used to prosecute alcohol-impaired drivers. Proposals have been put forward ranging from 2 ng/ml to 5 ng/ml tetrahydrocannabinol (THC) in whole blood. The science on this issue is clear: it is not possible to identify a valid impairment standard for marijuana or any other drug equivalent to the 0.08 g/dl limit for alcohol.

Alcohol is a poor model for studying the impairing effects of drugs because it is metabolized in simpler ways. Unlike alcohol, there is no close relationship between blood levels of drugs (or drug metabolites) and impairment. The vast number of impairing drugs and drug combinations often used with marijuana prevent any single measure from effectively covering all drivers. For example, a combination of low levels of alcohol and low levels of marijuana is severely impairing. Tolerance is another important factor preventing setting blood limits for marijuana and other drugs.  The Obama administration has strongly endorsed the implementation of drug    laws which specify that the presence of THC or marijuana metabolites (as well as other drugs) in a driver’s system is itself (i.e.“ per se”)   a criminal violation.   Zero tolerance laws use the limits of detection, the lowest concentration needed to reliably detect a drug.

Drastically different from zero tolerance, the marijuana legalization measure passed in 2012 in Washington State included a 5 ng/ml THC    limit for drivers age 21 and older. The 5 ng/ml  limit provides the appearance of protecting the public, but in reality it only protects marijuana users driving under the influence of marijuana from prosecution. Nearly all marijuana users test below 5 ng/ml of active THC in blood only a few hours after their last use.  A study of impaired drivers in Sweden with measurable THC in blood (>0.3 ng/ml) showed that 43% had THC concentrations less than 1 ng/ml; 61% had THC concentrations below 2 ng/ml 2  and over 90% of had THC levels under 5 ng/ml even though all of these drivers were judged to be impaired.

Because of the unavoidably long delay between arrest and blood collection, it is certain that THC concentrations were higher when these drivers were stopped for suspicion of drugged driving because of rapidly declining THC levels after marijuana use stops. THC concentrations were higher when drivers did not have other detected drugs in their blood “suggesting either more recent use or more frequent use of cannabis in these individuals.” Researchers concluded that the majority of drivers impaired by recent marijuana use would not be identified at cutoffs between 3 ng/ml and 5 ng/ml because THC is rapidly cleared from the blood after smoking marijuana. Therefore, under a 5 ng/ml THC  limit, only 10% of the drivers identified as impaired in this study would have been prosecuted.

Although Washington’s 5 ng/ml THC  limit is a poor policy for public safety, the law remains stronger than the 5 ng/ml THC permissible inference limit signed into law in Colorado after several previous failed attempts to pass      marijuana bills. While under the Washington law, a driver arrested for suspicion of drugged driving who tests at or above 5 ng/ml THC is in violation of the  law, in Colorado there is merely an inference that the same driver was under the influence when arrested and the driver can fight the charge in court. Given that over 70% of drivers in Colorado arrested for suspicion of driving under the influence of marijuana test below 5 ng/ml THC, these drivers are unlikely to be prosecuted at all.13 Moreover, the “permissible inference” will give almost all of the remaining 30% of arrested drivers a free pass to drive stoned. Underage drivers in Washington are subject to a zero tolerance      limit while in Colorado minors are subject to the same 5 ng/ml permissible inference limit as drivers age 21 and older.

Michigan uses the zero tolerance   standard for all Schedule I controlled substances, including marijuana; however, in May 2013, the Michigan Supreme Court ruled that “medical” marijuana users were not subject to the zero tolerance  standard for marijuana. In cases of drugged driving by an approved “medical” marijuana user, the state must prove the driver was impaired by marijuana at the time of arrest. This is similar to the way drivers impaired by

legally prescribed controlled drugs are treated in many states. In these states, drivers with valid prescriptions for controlled drugs can be prosecuted for drugged driving using the impairment standard. The prosecution of these drivers under the impairment standard is more challenging and less likely to be successful. The proliferation of drivers using “medical” marijuana has reignited calls for the development of a marijuana impairment standard.

The U.S. Department of Transportation (DOT) provides an important precedent for the use of the zero tolerance      standard.   DOT has successfully used this standard for nearly three decades for all safety-sensitive personnel including commercial drivers, airline pilots and train engineers. Any detected evidence of recent marijuana use is a violation because it is incompatible with the safe operation of vehicles. Either this standard is unwarranted for the people engaged in these safety-sensitive actions or it is the standard that should be applied to all motor vehicle drivers. The Institute for Behavior and Health, Inc. (IBH) strongly supports that the zero tolerance standard be applied to all drivers to protect the public safety on the nation’s roads and highways.

Advocates for permissive marijuana laws fear that the implementation of zero tolerance – or even in Colorado fear that 5 ng/ml – THC  drugged driving laws will translate to law enforcement officers targeting innocent marijuana users who will be wrongly prosecuted for impaired driving. Their concerns in part stem from a misunderstanding of the enforcement and drug and alcohol testing procedures related to driving under the influence (DUI). Individuals arrested for DUI have demonstrated behavioral impairment warranting their arrest before they are tested for alcohol or drugs. After arrest, these drivers now are tested for the presence of alcohol at the police station. If drivers produce a BAC of 0.08 g/dl (or higher), the testing procedure almost always stops. Typically only drivers arrested for impairment with low or zero BACs are tested for the presence of drugs. This means that only drivers who have already been arrested for being impaired will be drug tested.

Marijuana advocates also fear  drugged driving laws because of a misperception that most drivers testing positive for marijuana will not be impaired and will only test positive for marijuana (or its metabolites) because of use that occurred long before the arrest. As noted, drivers are tested for drugs only after they are arrested for DUI, or alternatively, if they are involved in serious or fatal crashes depending on the state procedures. No matter the circumstances under which drug testing of drivers takes place, the testing is unfortunately almost always long-delayed. Drug testing of DUI suspects typically is administered between 90 and 120 minutes after arrest while drug testing of injured drivers is done a few hours or longer after crashes.

Crucially important new research has shown that daily chronic marijuana users show observable deficits in driving skills as long as three weeks of abstinence compared to controls. It is possible that impairment was even longer lasting given that subjects were not tested after three weeks following their last use of marijuana. This is part of a large body of research that supports the use of the zero tolerance limit for marijuana.

Meta-analyses of epidemiological studies have concluded that smoking marijuana doubles risk of motor vehicle crash.   Studies of drivers involved in motor vehicle crashes support this conclusion. A study of seriously injured drivers admitted to a Maryland Level-1 shock trauma center showed that 26.9% of all seriously injured drivers tested positive for marijuana; half of drivers age 16 to 20 were positive for marijuana. A study of fatally injured drivers in Washington State showed 12.7% tested positive for marijuana and that among alcohol-positive drivers, 17.3% also tested positive for marijuana. The combination of marijuana use and alcohol is of great concern as evidence shows that low doses of marijuana combined with low doses of alcohol causes severe impairment. These data also show that combining alcohol and marijuana is common among seriously injured and fatally injured drivers.

Despite the evidence that marijuana use by drivers is a serious threat to public safety, there has been limited implementation and enforcement of drugged driving laws nationally, in part due to the widespread misperceptions actively spread by marijuana advocates who seek to limit any restrictions on drivers who use marijuana. Letting drivers arrested for DUI who test positive for marijuana walk away with no charge is a serious highway safety risk. New research conclusively demonstrates the folly of this approach.

Source:   www.ibhinc.org.   June 10th 2013

 

In Brief

  • In 2002 and 2003, 21% of persons aged 16 to 20 reported that they had driven in the past year while under the influence of alcohol or illicit drugs
  • Among persons aged 16 to 20, whites and American Indians/Alaska Natives were more likely to report DUI than other racial/ethnic groups
  • In 2002 and 2003, approximately 4% of persons who reported DUI in the past year had been arrested and booked for DUI in the past year

Motor vehicle crashes were the leading cause of death among young persons aged 16 to 20 in 2002.(Ref.1).   In that year, 6,327 persons aged 16 to 20 were involved in fatal crashes, representing a 10% increase since 1999. In addition, 29% of drivers aged 15 to 20 who were killed in motor vehicle crashes in 2002 had been drinking alcohol.(Ref.2) The National Survey on Drug Use and Health (NSDUH) asks persons aged 12 or older if they had driven a vehicle while under the influence of alcohol or illicit drugs in the past year (Ref.3) and if they had been arrested for driving under the influence (DUI).(Ref.4) The survey also asks about the use of alcohol and any illicit drugs in the past year and past month. Alcohol measures used in this report include any past month use, binge use, and heavy use. Binge alcohol use is defined as drinking five or more drinks on the same occasion (i.e., at the same time or within a couple of hours of each other) on at least 1 day in the past 30 days. Heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of 5 or more days in the past 30 days; all heavy alcohol users also are binge alcohol users. NSDUH defines “illicit drugs” to include marijuana/hashish, cocaine (including crack), inhalants, hallucinogens, heroin, or prescription-type drugs used non-medically.

This report presents the prevalence of DUI involving alcohol or illicit drugs, as well as the prevalence of being arrested for DUI among persons aged 16 to 20.5 To improve the reliability of estimates for population subgroups, all estimates presented in this report are annual averages based on combined data from the 2002 and 2003 NSDUH. However, the prevalence of DUI involving alcohol or illicit drugs among persons aged 16 to 20 was lower in 2003 (20%) than in 2002 (22%).
Prevalence of Substance Use and DUI
In 2002 and 2003, an annual average of 44% of persons aged 16 to 20 had used alcohol in the past month, 30 % were binge alcohol users, and 10% were heavy alcohol users. Approximately 38% of this age group had used an illicit drug in the past year.

In 2002 and 2003, more than 4 million persons (21%) aged 16 to 20 reported DUI involving either alcohol or illicit drugs in the past year. In this age group, 17% reported past year DUI involving alcohol, 14 % reported DUI involving illicit drugs, and 8% reported DUI involving a combination of alcohol and illicit drugs used together.

Demographic Differences in DUI

Among persons aged 16 to 20, older persons had a higher reported prevalence of DUI involving alcohol or illicit drugs than those who were younger. For example, persons aged 20 were nearly 3 times more likely to have driven under the influence than persons aged 16 (28 vs. 10%). Among all persons aged 16 to 20, males (24%) were more likely to report DUI involving alcohol or illicit drugs than females (18%). Among racial/ethnic groups, whites (26%) and American Indians/Alaska Natives (28%) were more likely to report DUI involving alcohol or illicit drugs than members of other racial/ethnic groups.

 In 2002 and 2003, approximately 25% of persons aged 16 to 20 who lived in the Midwest reported DUI involving alcohol or illicit drugs in the past year compared with approximately 20% in the South and 19 % of persons in this age group in the Northeast and West.(Ref.6). The prevalence of DUI involving alcohol or illicit drugs was  highest among persons who  lived  outside  of metropolitan  statistical areas  (MSAs)  

(25%), followed by persons who lived in small MSAs (23%) and persons who lived in large MSAs
(19%).(Ref.7).

 Prevalence of Being Arrested for DUI among Those Reporting DUI
Among the estimated 4.2 million persons aged 16 to 20 in 2002 and 2003 who reported DUI involving alcohol or illicit drugs in the past year, approximately 4% (169,000 persons) indicated they had been arrested and booked for DUI involving alcohol or drugs in the past year.(Ref.8).  The percentage of this group who reported being arrested for DUI was higher among males than among females (6 vs. 2%).
End Notes
1. Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. (2004, November 30). WISQARS leading causes of death reports, 1999 – 2002. Retrieved December 2, 2004, from http://webapp.cdc.gov/sasweb/ncipc/leadcaus10.html

2. National Highway Traffic Safety Administration. (2003, August). Traffic safety facts 2002: Young drivers.  from http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/TSF2002/2002ydrfacts.pdf   Dec.2 2004

3. Respondents were asked, in three different questions, if during the past 12 months they had driven a vehicle while under the influence of (a) alcohol only, (b) illicit drugs only, or (c) a combination of alcohol and illicit drugs used together. Responses to these questions then were recoded to determine the prevalence of DUI involving (a) alcohol, (b) illicit drugs, (c) either alcohol or illicit drugs, or (d) both alcohol and illicit drugs.

4. Respondents were asked if during the past 12 months they had been arrested and booked for DUI involving alcohol or illicit drugs.

5. Persons aged 15 or younger were not included in these analyses because a substantial portion of persons aged 15 or younger are prohibited from driving by State laws.

6. The Midwest has 12 States: IL, IN, IA, KS, MI, MN, MO, NE, ND, OH, SD, and WI. The South has 17 States: AL, AR, DC, DE, FL, GA, KY, LA, MD, MS, NC, OK, SC, TN, TX, VA, and WV. The Northeast has 9 States: CT, MA, ME, NH, NJ, NY, PA, RI, and VT. And the West has 13 States: AK, AZ, CA, CO, HI, ID, MT, NM, NV, OR, UT, WA, and WY.

7. Large metropolitan areas have a population of 1 million or more. Small metropolitan areas have a population of fewer than 1 million. Non-metropolitan areas are outside metropolitan statistical areas (MSAs), as defined by the Office of Management and Budget. See the U.S. Bureau of the Census. (2003, June 12). About metropolitan and micropolitan statistical areas. Retrieved December 1, 2004, from http://www.census.gov/population/www/estimates/aboutmetro.html

8. This excludes an estimated 38,000 persons who reported they had been arrested and booked for DUI in the past year but indicated elsewhere that they had not driven under the influence of alcohol or drugs in the past year.

The National Survey on Drug Use and Health (NSDUH) is an annual survey sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA). Prior to 2002, this survey was called the National Household Survey on Drug Abuse (NHSDA). The 2002 data are based on information obtained from 68,126 persons aged 12 or older, including 16,723 persons aged 16 to 20. The 2003 data are based on information obtained from 67,784 persons aged 12 or older, including 16,167 persons aged 16 to 20. The survey collects data by administering questionnaires to a representative sample of the population through face-to-face interviews at their place of residence.
The NSDUH Report is prepared by the Office of Applied Studies (OAS), SAMHSA, and by RTI International in Research Triangle Park, North Carolina. (RTI International is a trade name of Research Triangle Institute.)
Information and data for this issue are based on the following publications:
Office of Applied Studies. (2003). Results from the 2002 National Survey on Drug Use and Health: National findings (DHHS Publication No. SMA 03–3836, NSDUH Series H–22). Rockville, MD: Substance Abuse and Mental Health Services Administration.

Office of Applied Studies. (2004). Results from the 2003 National Survey on Drug Use and Health: National findings (DHHS Publication No. SMA 04–3964, NSDUH Series H–25). Rockville, MD: Substance Abuse and Mental Health Services Administration.

 

Source: The NSDUH Report (SAMHSA). http://www.oas.samhsa.gov Dec. 31,2004,
Filed under: Transport (Papers) :
Drugged Driving as Common as Alcohol-Impaired Driving Among Teens

Each day, more than 9,000 new driver’s licenses are issued to 16- and 17-year-olds nationwide, the very same age group that is at greatest risk for marijuana use, and a 2005 survey reveals that these teens say that cars are the second most popular place for smoking marijuana. The Office of National Drug Control Policy (ONDCP) is partnering with driving schools and other leading health, safety and youth-serving organizations to warn parents of the prevalence and dangers of drugged driving and to provide information to help teens “Steer Clear of Pot.”

More than 2.9 million driving-age teens reported lifetime use of marijuana, and last year more than 750,000 16- and 17-year-olds reported driving under the influence of illicit drugs. According to the 2004-2005 PRIDE Surveys, when asked where they use, approximately one in seven (14%) high school seniors cited “in a car,” making cars the second most popular location after at “a friend’s house” (20.4%).

“Parents need to realize that drugged driving is nearly as common today among teens as alcohol-impaired driving,” said John P. Walters, Director, National Drug Control Policy. “Marijuana impairs many of the skills required for safe driving, such as concentration, coordination, perception and reaction time, and these effects can last up to 24 hours after smoking the drug — It is critical that parents know the dangers associated with drugged driving and are vigilant in monitoring their teen drivers, especially young, less experienced drivers.”

Monitoring the Future data shows that approximately one in six (15%) teens reported driving under the influence of marijuana, a number nearly equivalent to those who reported driving under the influence of alcohol (16%). A recent study from a large shock trauma unit found that 19 percent of automobile crash victims under age 18 tested positive for marijuana.

“Getting a driver’s license is a milestone in a teen’s life that goes beyond the road to symbolize independence and freedom,” said Thomas “Buddy” Gleaton, Ed.D., President, PRIDE Surveys. “In the more than 20 years that PRIDE Surveys has been tracking teen drug use, teens consistently report engaging in risky behaviors in cars. Parents need to keep a watchful eye to be effective in reversing these trends.”

ONDCP’s National Youth Anti-Drug Media Campaign is providing parents and teens with information about the risks of drugged driving through a renewed “Steer Clear of Pot” initiative. The Media Campaign will underscore the harmful effects of teen marijuana use and drugged driving through the promotion of free materials, including a “New Drivers Kit” for teens and parents, available with other new content on the Media Campaign’s Web site for parents, http://www.TheAntiDrug.com .

In addition, “Steer Clear of Pot” partners will distribute drugged driving and marijuana prevention materials to driver’s education teachers, teens, and parents nationwide:

— The American College of Emergency Physicians will inform its nationwide membership base of 15,000 in 49 chapters of “Steer Clear of Pot” resources through its newsletter and Web site;

— The Driving School Association of the Americas will include information about the initiative in its magazine, The Dual News, which is distributed to 8,000 professional driving schools and 50,000 driving school educators, and will promote available resources on the organization’s Web site;

— The Emergency Nurses Association will inform its 28,000 members about available resources through its monthly newsletter; and

— GEICO, the fifth-largest private passenger auto insurer in the United States, has incorporated the Media Campaign’s messages into its existing “Can I Borrow the Car?” teen driving and safety materials and is providing co-branded versions of those materials through the Campaign’s “New Drivers Kit.” The company continues to distribute co-branded “Steer Clear of Pot” materials and promote the Media Campaign’s resources to its 5.5 million policyholders and 22,000 GEICO associates.

“Driver’s education and behind-the-wheel training are at the foundation for developing safe driving skills,” said Bradley Huspek, President, Driving School Association of the Americas. “Parents and driving instructors play a critical role in educating teens about being responsible drivers and steering clear from drugs.”

Experts say parental supervision and setting clear rules are associated with less risky teen behavior. A recent SADD/Liberty Mutual Group report found that nearly 60 percent of teens who drive say their parents have the most influence on their driving, followed by 27 percent who say their friends are most influential. Parents can take action and help their teen “steer clear of pot” with simple steps such as:

— checking the car for signs of drug paraphernalia;

— setting limits on driving in risky conditions;

— knowing where their teen is going and what route they intend to drive; and

— reinforcing safe driving practices by driving together.

Since its inception in 1998, the National Youth Anti-Drug Media Campaign has conducted outreach to millions of parents, teens and communities to reduce and prevent teen drug use. Counting on an unprecedented blend of public and private partnerships, non-profit community service organizations, volunteerism, and youth-to-youth communications, the Campaign is designed to reach Americans of diverse backgrounds with effective anti-drug messages.

For more information on the ONDCP National Youth Anti-Drug Media Campaign, visit

http://www.MediaCampaign.org

 

Source: WASHINGTON, /PRNewswire Nov. 28 .2005
Filed under: Transport (Papers) :
Background

The Road Safety Monitor, a national telephone survey conducted each year involving Canadian drivers indicates that drug impaired driving is seen as second only to alcohol impaired driving as a serious issue and that illicit drugs are seen as a more serious problem than prescription or over the counter drugs. Overall, 17.7%, or 3.7 million Canadian drivers report driving within two hours of using illicit, prescription or over the counter drugs.

Collisions remain a major cause of death and injury in Canada, and concerns about the role of cannabis in road safety in this country date back many years. Much less is known about the impact of cannabis on road safety than the impact of alcohol, in part because of the much greater difficulty involved in measuring the presence and amount of cannabinoids compared to alcohol. However, there is renewed interest in this issue stimulated in part by proposed legislative changes on the part of the Government of Canada to reduce substantially the penalties for possession of small amounts of cannabis.

Objectives

The purpose of this paper is to provide an overview of available research and evidence on the potential impact of cannabis on road safety in Canada focusing on two areas: 1) research on the prevalence of cannabis use in Canada; and 2) research on the prevalence of driving after cannabis use in Canada.

Prevalence of Cannabis Use in Canada

Little information is available on the prevalence of cannabis use in Canada prior to the 1960s. However, in that decade, cannabis use increased substantially. While a variety of possible sources of information on cannabis in the Canadian population have been used over the years, including such measures as amounts of the drug seized by police and the number of individuals prosecuted by the courts for cannabis offences, the most direct and the most accurate measures of the prevalence of cannabis use are those derived from surveys. Although cannabis is an illegal drug and there are concerns that survey responses may be influenced by its legal status, research demonstrates that respondents to anonymous surveys, where there are no adverse consequences involved, generally provide valid responses.

Smart and Fejer presented one of the very first estimates of the prevalence of cannabis use in a Canadian population, based on a survey of a representative sample of residents of Toronto conducted in 1971. They found that 12.2% of males and 5.5% of females had used cannabis at least once in the preceding year. The prevalence of use differed substantially by age group and gender. Among males, 41.5% of those aged 18-25, 20.8% of those aged 26-30, and 1.8% of those aged 31 and over had used cannabis in the preceding year. Among females, 20.0% of those aged 18-25, 6.3% of those aged 26-30, and 1.8% of those aged 31 and over had used cannabis in the previous year. These data clearly demonstrate that, by the end of the 1960’s, cannabis use had become very common among young people.

Ogborne and Smart reported on cannabis use in the general population of Canada aged 15 and over based on the National Alcohol and Other Drugs Survey conducted in 1994. This survey was the largest representative survey with information on cannabis use ever made in Canada, with a sample size of 12,155. Use of cannabis at that time was relatively uncommon, but not rare. Only 7.3% of respondents reported using cannabis in the preceding year, and 2.0% reported using it as often as once per week. However, nearly a third (29%) reported that they had used cannabis at least once in their lives. Substantial regional differences were observed, with the proportion reporting use at least once in the past year ranging from a low of 4.9% in Ontario to a high of 11.4% in British Columbia.

While these data provide a valuable perspective on the use of cannabis across Canada, unfortunately there is little information on other important issues, such as change in rates of use over time. However, in Ontario a series of surveys has been conducted over the past 20 years that allow a picture of current use and changes in use over time in that part of the country.

The Use of Cannabis in Ontario

Repeated cross-sectional surveys conducted in Ontario by the Centre for Addiction and Mental Health provide the most comprehensive picture of the use of cannabis and other drugs use in Canada. These surveys have been conducted among the student population and adult population since the late 1970s.

A summary of recent data on the use of cannabis and other drugs (any use in the past year) among students in grades 7 and 126, and among adults aged 18-29 (young adults), 40-49 (the middle-aged) and 65 and over (seniors) showed cannabis is the most widely used illicit substance. Nearly half of grade 12 students reporting cannabis use at least once in the past year. It is worth noting that by grade 12 most students will have reached the age when they will be eligible to drive. Use of cannabis drops with increasing age, however, and is used by less than 2% of seniors. Use of other illicit drugs is much less common than the use of cannabis, with highest levels occurring for Hallucinogens and Ecstasy among grade 12 students. Not surprisingly, alcohol is the most commonly used substance.

Trends in Cannabis Use Over Time

information is presented on the proportion of students in Grades 7, 9, 11 and 13 who report using cannabis and alcohol between 1977 and 20016. While cannabis is used by a smaller proportion of students than alcohol; it is still used by a substantial minority of students. There have been important changes in the use of cannabis over time. The general trend appears to have been one of reduced use of cannabis and alcohol from the late 1970’s to the early 1990’s. The proportion reporting use of cannabis declined from a peak of 31.7% in 1979 to 11.7% in 1991. However, since the mid-1990’s self-reported use of both substances has increased, with 28.6% reporting cannabis use in 2001. Data is presented since 1977 on the proportion of the adult population (age 18 and above) who report using cannabis, drinking alcohol, or using cocaine at least once in the preceding 12 months. Cannabis use has continued among a much smaller proportion of the adult population than among students. Alcohol is used by the large majority of the adult population, while the use of cocaine is reported by only a very small percentage. The trends among adults are not as clear as those among the student population. For example, the proportion reporting use of alcohol has been relatively consistent, with perhaps a slight increase to the early 1990s followed by a slight decrease. Among users of cannabis and cocaine, enduring trends over time cannot be ascertained.

Prevalence of Cannabis Use and Driving in Canada: Estimates from Survey Data

Survey data on the prevalence of driving under the influence of cannabis are available. In the first reported data from the general population in Canada, Jonah reported on the prevalence of driving after use of cannabis at least once in the preceding 12 months. The survey included 9943 persons aged 16-69, obtained through random digit dialing. Jonah found that the prevalence of DUIC varied with age. While the prevalence of DUIC was relatively low, it was higher in younger age groups. Jonah also observed that DUIC was significantly associated with a variety of other risk behaviours, such as driving after drinking, use of illicit drugs other than cannabis, and collision involvement.

Conclusions

The data presented here indicate that cannabis use is relatively common in Canada, particularly among young people. The prevalence of use appears to have increased substantially in the 1960s and ‘70s, while since then some fluctuations have occurred. Driving after cannabis use is less common, but among cannabis users it does appear to occur with some frequency. In particular, young cannabis users appear more likely to report DUIC. Among high school students, DUIC appears to occur as frequently, or more frequently, than driving after drinking. These data provide grounds for concern about this behaviour, particularly among younger drivers. Further research on the prevalence of DUIC in Canada, including differences between provinces, is needed.

 

Source: CAMH Population Studies eBulletin, May/June 2003, No. 20. Toronto:
Centre for Addiction and Mental Health.
Filed under: Transport (Papers) :

Frequently Asked Questions About Pot & Driving

Introduction

On November 21, 2005, the Canadian Public Health Association, with funding from Canada’s Drug Strategy, Health Canada, launched a Pot and Driving campaign (http://potanddriving.cpha.ca) to raise awareness among young Canadian drivers and passengers of the risks of cannabis-impaired driving. Campaign materials include:

 

  • A poster of airplane pilots smoking up with the campaign message, “If it doesn’t make sense here, why does it make sense when you drive?”
  • 10 Questions (to provoke thought and dialogue)

  • The thinking behind the questions (to encourage discussion)

  • This FAQ (to inform the discussion).  This FAQ provides information on a range of issues related to cannabis use in the context of driving. It draws on up-to-date, relevant studies and surveys, insights given by key informants from Canada and several other countries, and the opinions of young Canadians who took part in focus groups held in several locations across the country.

1. Why a pot and driving focus?
What do we mean by ‘pot’?

We use the word ‘pot’ in our materials to refer to any drug derived from the cannabis plant, including marijuana (which is made from the leaves and buds), as well as hashish and hashish oil (made from plant resin). We chose this word because it is short and easy to say; more importantly we chose it because focus group participants were unanimous in saying that along with the word ‘weed’, ‘pot’ is the most common word used to refer to cannabis in both English and French Canada.
Canadians between the ages of 14 to 25 have one of the highest rates of pot use in the world. Many young Canadians who use pot see it as a mild, mainstream drug with no significant negative consequences. While most young drivers and passengers have little tolerance for alcohol-impaired driving, they commonly regard pot and driving as risk free.

Recent research on pot is showing that it can play an important role in road vehicle crashes, especially when combined with driver inexperience and difficult road conditions. Road accidents are often the result of a combination of factors and pot can be one of them.

Pot is the most popular drug used by Canadians 14 to 25 years-of-age, after alcohol and tobacco. Drug-use surveys indicate that the rate of driving under the influence of pot surpasses that of alcohol. Alcohol has been the subject of impaired-driving awareness efforts for several decades and tobacco is not a risk for driving. It is time to put the focus on pot.

2. How does cannabis affect driving ability?

Driving skills are affected in specific ways when a person has consumed a certain amount of pot. This impairment increases with the amount of THC (the compound that gives pot its high) a person has in his/her system. While drivers have been found to do certain things to adapt to their impairment, like slowing down, this attempt to compensate does not eliminate the risks of driving high.

It has long been established that pot affects tracking ability, meaning that drivers who are under the influence of a certain dose of THC have been found to have a harder time following their lane. Pot reduces a driver’s ability to perceive changes in the relative speed of other vehicles and to adjust his/her own speed accordingly.

Pot has been found to increase the reaction time needed to respond to an emergency decision-making task, such as adapting to changes in speed of the vehicle ahead or to the vehicle’s brake lights. A driver needs to notice something in order to respond to it and that has to do with the driver’s attention. Because pot disturbs concentration and short-term memory, a driver has a harder time being attentive to events and situations on the road that can have important consequences for road safety.

3. Who drives under the influence of pot?

What do we mean by ‘driving’?

When we use the phrase ‘driving a vehicle’ we are referring to the use of any kind of motor vehicle, including cars, trucks, motorbikes, ATVs, planes, motorboats and snowmobiles. We generally use the word ‘driving’ to imply the use of both on and off-road vehicles. We do not wish to suggest that off-road driving is less of a concern when it comes to drug use.

Several student surveys in Canada have found a high rate of pot use among students in high school, with the rate increasing with age/grade. Male students have a higher rate of use than female students. The likelihood that a person will drive high depends on how frequently they use pot. Daily pot users have the highest rate of driving high while occasional users have the lowest rate.

Cannabis use by Canadian adolescents is reported to be among the highest in the world. The 2002 Nova Scotia Student Drug Use Survey found that 22% of students surveyed used marijuana in the month before the survey, while 5% used it every day. The 2002 Alberta Youth Experience Survey indicated that cannabis use by Aboriginal youth (52%) was almost twice that of non-aboriginal youth (27%). One in five Ontario high school student respondents in the 2003 Ontario Student Drug Use Survey reported driving one hour after using cannabis during the past six months.

Drugged driving is not isolated to young Canadians or to Canadians who use illegal drugs. Older drivers are more likely to drive impaired by prescribed medications; younger drivers are most likely to drive while affected by illegal drugs, including cocaine and pot. It is young, male, frequent pot users, who are most likely to drive high.

4. Why focus on mainstream teens?

Surveys conducted in Canada and in countries such as Australia have shown that driving under the influence of cannabis is rare in the general population but common among cannabis users, a group concentrated in those 14 to 25 years-of-age. For this campaign, we decided to target mainstream youth since data indicates that the rate of cannabis use is approaching the rate of alcohol consumption among youth in Canada. Pot has become mainstream.

We spoke to several groups of young Canadians 15-25 years-of-age about their experiences with pot and driving. Generally, older participants were convinced that driving high was not a problem and said they were unlikely to change their minds about doing it. Participants who were not yet driving or were anticipating learning how to drive appeared to be more open to the suggestion that mixing pot and driving, like mixing alcohol and driving, could put them and their passengers at risk. So we decided the campaign should focus on mainstream Canadians 14-18 years-of-age.

5. Who is likely to be a passenger of a driver who is high?

Studies have found that a person’s likelihood of being a passenger of a driver who has used pot within an hour or two of driving, or uses it while driving, increases with high school grade. Gender does not seem to be a factor, although our focus group participants did provide some indications that female passengers may be more likely to be a passenger with a boyfriend who is high than a female friend.

6. How long after using pot are driving skills affected?

Cannabis impairs driving skills most severely during what is known as the acute phase, which typically lasts for up to 60 minutes after smoking. This is followed by post-acute (the phase after the acute one) and residual phases. The residual phase is 150 minutes or more after smoking, during which impairment subsides rapidly. The degree of impairment during the residual phase depends on the amount of THC consumed. After smoking a so-called typical dose (about 20 mg) of THC, the residual phase lasts 2-3 hours.  *

7. What about ‘burnout’?

Burnout is roughly equivalent to the ‘hangover’ associated with alcohol. Very little is known about the effect of ‘burnout’ on driving, although some focus group participants flagged it as a significant issue for driving. Some even suggested they felt safer driving high than driving during burnout. Since burnout is characterized by fatigue, studies of the effect of fatigue on driving might be applied to burnout.

What is drugged-driving?

If your ability to drive a motor vehicle is affected because you have taken a drug, a combination of drugs, or drugs and alcohol (which is also a drug although it is usually referred to separately), you are drugged-driving. A number of medications prescribed by doctors as well as some overthe- counter remedies are known to affect a person’s ability to drive safely. Several illegal drugs are also known to affect driving skills.

As is the case with alcohol, risk increases with dose. However, regular users have been found to experience less effect from the same dose. Unlike alcohol, pot’s THC concentrations can vary significantly from batch to batch.

Since cannabis is illegal and unregulated, there is no standardized consumption limit as there is for drinking alcohol and driving. In experimental research, drivers are given what would be considered an ‘average’ dose of THC and then observed as they perform a number of driving tasks on the road under controlled conditions. For the sake of safety, these tests cannot put drivers in situations that would likely lead to accidents.

Since cannabis is illegal and unregulated, there is no standardized consumption limit as there is for drinking alcohol and driving. In experimental research, drivers are given what would be considered an ‘average’ dose of THC and then observed as they perform a number of driving tasks on the road under controlled conditions. For the sake of safety, these tests cannot put drivers in situations that would likely lead to accidents.

9. Can a drug that is used to treat disease also affect driving?
Why the term pot and driving?

Phrases like alcohol-impaired driving, drunk-driving, drinking and driving or driving under the influence of alcohol (DUIA) are well known. Equivalent terms referring to drug use and driving– including drug-impaired driving, drugged driving and driving under the influence of drugs (DUID)–are less well known, although that is changing.We have chosen to use more informal phrases such as driving high, mixing pot and driving or simply pot and driving.

10. How does pot compare with alcohol as a threat to road safety?

In Canada, driving under the influence of alcohol is widely regarded as both dangerous and socially unacceptable. The evidence to date supports the claim that alcohol is still one of the most important contributors to crash risk injury or death. The increasing evidence of the contribution of drugs other than alcohol to road crashes, whether they are consumed with alcohol or by themselves, has led to a number of efforts to increase awareness of the potential road safety hazards of these drugs. The perception that pot is relatively risk-free when compared to alcohol may help explain why recent drug use surveys in Canada have found that the rate of driving under the influence of pot surpasses the rate of driving under the influence of alcohol among young drivers and passengers.

11. Why not adopt a law enforcement message?

Law enforcement has played an important role in changing attitudes about alcohol-impaired driving. However, fear of being caught and prosecuted for driving high seems not to be a significant concern for many young people.

Focus group participants indicated that parents could be a deterrent if for no other reason than they usually control the keys to the car. Focus group participants also indicated that it is tougher to fool parents: “When I’m driving high I’m more afraid of my mom because cops have no way of telling. Whereas if my mum says ‘You’re high’, I’m not going to say ‘I’m not” because I know she’s not going to believe me.”

12. What does Canadian law say about drugs and driving?

It is the effects of pot on driving—not the legal status of pot—that makes its use illegal both before or while taking control of a motor vehicle.

Article S. 253 of the Canadian Criminal Code says that: “Everyone commits an offence who operates a motor vehicle or operates or assists in the operation of an aircraft or railway equipment or has the care or control of a motor vehicle, vessel, aircraft or railway equipment, whether it is in motion or not, (a) while the person’s ability to operate the vehicle, vessel, aircraft or railway equipment is impaired by alcohol or a drug.”

In the Canadian Criminal Code, laws on impaired driving are distinct from laws that say whether it is legal or not to produce, sell or use a particular drug. In other words, the fact that a drug is legal or illegal has nothing to do with the issue of driver impairment. As an example, it is legal to drink alcohol for age-of-majority Canadians but it is illegal to drive while impaired by alcohol.

13. Can law enforcement officers identify and charge drivers who are impaired by cannabis?

What is THC?

THC is the primary psychoactive compound found in cannabis. A psychoactive drug is one that alters brain function, resulting in temporary changes in perception, mood, consciousness, and behaviour.

As noted above, current law makes it a criminal offense to drive while impaired by cannabis and other drugs. The federal government is considering tabling Bill C-16, which would amend the Impaired Driving section of the Canadian Criminal Code in order to allow police officers to require drivers to undergo a Standardized Field Sobriety Test if the officer believes the person is driving under the influence of a drug. If a driver fails the sobriety test, the officer would have reasonable grounds to believe the driver has committed a drug-impaired offence and can require the driver to submit to a Drug Recognition Expert (DRE) evaluation at the police station. Police departments across the country have begun to train officers to conduct DRE assessments.

If a person fails these procedures, police would have reasonable grounds to demand a sample of bodily fluids, whether blood, urine or saliva. Charges can only be laid after the presence of drugs in bodily fluids is confirmed by laboratory analysis. A driver who refuses to complete the sobriety test or provide bodily fluid samples would be criminally charged, as is the case for drivers who refuse sobriety test and breathalyzers when they are suspected of driving while impaired by alcohol.

14. Will changes to the Criminal Code relating to cannabis possession and use (Bill C-17) affect laws and law enforcement relating to cannabis-impaired driving?

Under the legislative changes proposed in Bill C-17, possession and use of cannabis will remain illegal, but anyone found to have small amounts of cannabis for personal use would only be fined. If these proposed changes to the Criminal Code become law, driving high will likely be more, not less, subject to penalty than it is today. For example, possession of 15 grams or less of cannabis will be punishable by a fine of $150 for an adult and $100 for a person under the age of 18. However, where aggravating factors such as driving a car exist (even if the driver is not high), the fine would be $400 for an adult and $250 for a person under the age of 18.

The views expressed herein do not necessarily express the views of Health Canada

Cannabis and Driving: Key Points of Reference and Bibliography

1. “Educational and policy initiatives directed at new drivers have failed to adequately inform new drivers about the potential consequences of driving under the influence of cannabis…This speaks to the role of organizations involved in health promotion and education around impaired driving who have, until recently, focused almost exclusively on the issue of drinking and driving and paid less attention to the drug-driving issue.” (7-8)

“Among the general adolescent population in Atlantic Canada, driving under the influence of cannabis has become a prevalent activity surpassing driving under the influence of alcohol, and it has played an important role in motor vehicle collision risk, independent of drinking and driving, driver experience, and other risk factors.” (8)

Asbridge et al. (2005)Motor vehicle collision risk and driving under the influence of cannabis: Evidence from adolescents in Atlantic Canada

2. “The present study presents good evidence that drivers killed in motor vehicle crashes and taking psychoactive drugs, particularly cannabis and strong stimulants, or two or more drugs in combination were more likely to be responsible for the crash than those taking neither drugs nor alcohol. Moreover, the combination of psychoactive drugs with alcohol further increased the likelihood that drivers caused the crash in which they died. We conclude that THC, amphetamines and combinations of psychoactive drugs significantly increase drivers’ risk of a serious road crash.” (247)

Drummer et al. (2004) The involvement of drugs in drivers of motor vehicles killed in Australian road traffic crashes

3. “There is considerable evidence that cannabis does impair ability to perform the multiple functions required to drive a car safely. Although the deleterious effects of cannabis are manifestly not as severe as those of alcohol, they are more complex due to its sedative and stimulant properties; nevertheless several countries have proscribed the use of cannabis by drivers and have introduced legislation to that effect. The impetus behind these measures seems to be several fold — the increasing use of cannabis, especially by younger and therefore more inexperienced drivers; the increasing volume of traffic, dependence on personal vehicles for transport and concomitant increase in accidents; studies highlighting the effects of cannabis on brain function and increased public awareness of the hazards associated with driving and substance abuse; and not least the costs to society and individuals of road traffic casualties.” (330) Hadorn. (2004) A review of cannabis and driving skills

4. “One of the clear messages to emerge from the research reviewed is that there is a need to examine the effects of cannabis in situations where the driver is required to perform several tasks simultaneously or when confronted with a situation that requires a rapid adaptive response. Furthermore, there has been little research examining the effects of cannabis, alone and in combination with alcohol and other drugs, across a range of levels of driving experience.” (xii)

“As previous researchers have suggested, it is critical to examine the effects of cannabis when the driver in placed in situations involving increased mental load. This represents a shift in the experimental research away from looking simply at the effects of cannabis on traditional measures of driving performance such as lateral placement and speed, and a move towards supplementing traditional measures with investigation of the effects of cannabis when a driver is placed in an unexpected high accident risk situation that requires an immediate decision and response.” (31)

Lenné et al. (2004) Cannabis and Road Safety: A Review of Recent Epidemiological, Driver Impairment, and Drug Screening Literature

5. “Surveys that established recent use of cannabis by directly measuring THC in blood showed that THC positives, particularly at higher doses, are about three to seven times more likely to be responsible for their crash as compared to drivers that had not used drugs or alcohol. Together these epidemiological data suggests that recent use of cannabis may increase crash risk, whereas past use of cannabis does not.” (109)

Ramaekers et al. (2004) Dose related risk of motor vehicle crashes after cannabis use

6. “In terms of road safety the results show a clear worsening of driver capability following the ingestion of cannabis or the ingestion of cannabis and alcohol together at the doses used, in comparison with placebo (i.e. having taken neither). Within the sample of drivers, the effects of alcohol (at a dose of just more than half of the UK legal limit) and cannabis taken together were slightly greater than with cannabis alone. Given that other research has extensively shown the rapid increase in the risk of accident, particularly fatal accident, with increasing blood alcohol level, the present results show how important it is to avoid any combination of alcohol and cannabis, as well as avoiding alcohol and cannabis taken on their own, before driving or riding.” (2)

“Drivers under the influence of cannabis seem to attempt to compensate to some extent for the impairment (that they recognise) by driving more slowly, but there are some aspects of the driving task where cannabis-impaired drivers cannot compensate and where their performance deteriorates (e.g. staying in lane on a bend).” (2) Sexton et al. (2002) The influence of cannabis and alcohol on driving

7. “To the extent that drivers compensate for the effect of cannabis, they appear to be able to manage routine and low demand tasks, but the remaining cognitive resources may not sufficient to cope with peak and unexpected demands.” Smiley. (1999) Marijuana: On-road and driving simulator studies

Canadian Drug Use Surveys

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Cannabis and Piloting Studies

D.S. Janowsky et al. (1976) Marijuana effects on simulated flying ability. American Journal of Psychiatry 133: 384-388 and —-,—- (1976) Simulated flying performance after marijuana intoxication. Aviation, Space, and Environmental Medicine, 47: 124-128.

LEIRER, V.O. et al. (1991) Marijuana carry-over effects on aircraft pilot performance. Aviation, Space, and Environmental Medicine 62: 221-227.

NEWMAN. David G. (2004) Cannabis and its Effects on Pilot Performance and Flight Safety. Australian Transport Safety Bureau, 1-18.

*NDPA would draw your attention to the study which showed pilots could not safely land a plane 24 hours after smoking marijuana.  Marijuana Carry-Over Effects on Psychomotor Performance: A Chronicle of Research by Leirer, Yesavage & Morrow.  Stanford University School of Medicine

 

 

 

Source: www.potanddriving.cpha.

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