QUESTION = Does marijuana impair driving ability?

GENERATION = Pretty much not. There have been a few cases (especially with violent drivers) where weed (specifically, sativa) has been shown to reduce the chance of tripping, but in other instances, driving as drunk or high as you normally would wouldn't make it any worse (unless you got smashed with a jackpot). The main effect that weed has on driving is to produce adrenaline, which increases your heart rate and makes you calmer. This isn't the only effects of weed, and it does also cause you to have less control over your body - driving drunk usually feels a lot worse than driving drunk with a hefty heavy metal. Other chemicals that can help you retain your balance and control might make you less "flighty," however, so it's not the only effect of weed. One thing to note is that this effect isn't consistent across people who smoke weed. Women tend to have a lot higher rates of smoking, but men tend to have the opposite effect. Men who smoke tend to get more dizzy, less able to hold their breath, and make lots of slurred speech. 

RETRIEVAL #0 = Cannabis and impaired driving---involvement. Kelly, Darke and Ross show similar results, with laboratory studies examining the effects of cannabis on skills utilised while driving showing impairments in tracking, attention, reaction time, short-term memory, hand-eye coordination, vigilance, time and distance perception, and decision making and concentration. An EMCDDA review concluded that "the acute effect of moderate or higher doses of cannabis impairs the skills related to safe driving and injury risk", specifically "attention, tracking and psychomotor skills". In their review of driving simulator studies, Kelly et al. conclude that there is evidence of dose-dependent impairments in cannabis-affected drivers' ability to control a vehicle in the areas of steering, headway control, speed variability, car following, reaction time and lane positioning. The researchers note that "even in those who learn to compensate for a drug's impairing effects, substantial impairment in performance can still be observed under conditions of general task performance (i.e. when no contingencies are present to maintain compensated performance)." A 2012 meta-analysis found that acute cannabis use increased the risk of an automobile crash. An extensive 2013 review of 66 studies regarding crash risk and drug use found that cannabis was associated with minor, but not statistically significant increased odds of injury or fatal accident. The estimated 

RETRIEVAL #1 = Effects of cannabis---risk associated with cannabis use by drivers, other studies have not found increased risk. Cannabis usage has been shown in some studies to have a negative effect on driving ability. The British Medical Journal indicated that "drivers who consume cannabis within three hours of driving are nearly twice as likely to cause a vehicle collision as those who are not under the influence of drugs or alcohol". In "Cannabis and driving: a review of the literature and commentary", the United Kingdom's Department for Transport reviewed data on cannabis and driving, finding although impaired, "subjects under cannabis treatment appear to perceive that they are indeed impaired. Where they can compensate, they do...". In a review of driving simulator studies, researchers note that "even in those who learn to compensate for a drug's impairing effects, substantial impairment in performance can still be observed under conditions of general task performance (i.e. when no contingencies are present to maintain compensated performance)." A 2012 meta-analysis found that acute cannabis use increased the risk of an automobile crash. An extensive 2013 review of 66 studies regarding crash risk and drug use found that cannabis was associated with minor, but not statistically significant increased odds of injury or fatal accident. In the largest and most precisely controlled study of its kind carried out by the U.S. Department of Transportation’s National Highway 

RETRIEVAL #2 = Cannabis and impaired driving---do not indicate that drug use by drivers is risk-free." The British Medical Journal indicated that "drivers who consume cannabis within three hours of driving are nearly twice as likely to cause a vehicle collision as those who are not under the influence of drugs or alcohol". In "Cannabis and driving: a review of the literature and commentary", the United Kingdom's Department for Transport reviewed data on cannabis and driving, finding "Cannabis impairs driving behaviour. However, this impairment is mediated in that subjects under cannabis treatment appear to perceive that they are indeed impaired. Where they can compensate, they do, for example ... effects of driving behaviour are present up to an hour after smoking but do not continue for extended periods". The report summarizes current knowledge about the effects of cannabis on driving and accident risk based on a review of available literature published since 1994 and the effects of cannabis on laboratory based tasks. The study identified young males, amongst whom cannabis consumption is frequent and increasing, and in whom alcohol consumption is also common, as a risk group for traffic accidents. The cause, according to the report, is driving inexperience and factors associated with youth relating to risk taking, delinquency and motivation. These demographic and psychosocial variables may relate to both drug use and accident risk, thereby presenting an artificial relationship between use of drugs and accident 

RETRIEVAL #3 = Cannabis and impaired driving---Cannabis and impaired driving Cannabinoids present in the cannabis plant and its derived drugs are known to cause impaired driving in users, with effects on a driver similar to those of alcohol. Many jurisdictions have laws forbidding cannabis-impaired driving, and some have "per se" impairment levels determined by metabolites detected in body fluids. Section::::Legal background. Two main questions arise in the law surrounding driving after having ingested cannabis: (1) whether cannabis actually impairs driving ability, and (2) whether the common practice of testing for THC (the main psychoactive substance in cannabis) is a reliable means to measure impairment. On the first question, studies are mixed. Several recent, extensive studies--including one conducted by the National Highway Traffic Safety Administration and one conducted by the American Automobile Association (AAA)--show that drivers with detectable THC in their blood are no more likely to cause car crashes than drivers with no amount of THC in their blood. Others show that cannabis can impair certain abilities important to safe driving (such as reaction time, divided attention, and cognitive functions)--but "no studies" have been able to show that this increases the actual risk of crashing, or that drivers with THC in their blood cause a disproportionate number of crashes. On the second question, the studies that 

RETRIEVAL #4 = Cannabis and impaired driving---levels with impairment. As stated in a report to Congress produced by the U.S. Department of Transportation's National Highway Traffic Safety Administration, "[I]n contrast to the situation with alcohol, someone can show little or no impairment at a THC level at which someone else may show a greater degree of impairment." The report also noted that, in some studies, THC was detectable as late as 30 days after ingestion--even though the acute psychoactive effects of cannabis last only for a few hours. Section::::Effects on driving. While several studies have shown increased risk associated with cannabis use by drivers, other studies have not found increased risk. In the largest and most precisely controlled study of its kind carried out by the U.S. Department of Transportation’s National Highway Traffic Safety Administration to research the risks of cannabis and driving, it was found that other "studies that measure the presence of THC in the drivers' blood or oral fluid, rather than relying on self-report tend to have much lower (or no) elevated crash risk estimates. Likewise better controlled studies have found lower (or no) elevated crash risk estimates". The study found that "after adjusting for age, gender, race and alcohol use, drivers who tested positive for marijuana were no more likely to crash than those who had not used any drugs or 

RETRIEVAL #5 = Cannabis and impaired driving---that "there are no widely accepted methods for detecting impairment from marijuana". The U.S. drug czar Gil Kerlikowske said in 2012, "I'll be dead from old age, before we know the impairment levels" for cannabis. A 2017 Canadian government report stated "science is unable to provide general guidance to drivers about how much cannabis can be consumed before it is unsafe to drive". Some users seem to be able to perform risk compensation by driving slower or other behaviors, and some users appear to develop a physiological tolerance, making determining a standard impairment dose difficult. A 2010 study found "cannabis and alcohol acutely impair several driving‐related skills in a dose‐related fashion, but the effects of cannabis vary more between individuals because of tolerance, differences in smoking technique, and different absorptions of THC". A 2014 study found "no correlation between degree of impairment and THCA-A blood concentration". Because of these findings, some safety organizations have advocated that police use behavioral impairment tests instead of metabolite testing. Section::::Detection of impairment.:False indications of driving impairment. Testing for metabolites of THC, versus the actual THC intoxicant, can result in DUID convictions of users who aren't actually impaired. According to 

RETRIEVAL #6 = Cannabis and impaired driving---for cannabis (1.10) were lower than: antihistamines (1.12), penicillin (1.12), antianxiety meds (1.17), antidepressants (1.35), antiasthmatics (1.31), zopiclone (sleep medicine) (1.42), cocaine (1.66), and opiates (1.91). The study concluded: ""By and large, the increase in the risk of accident involvement associated with the use of drugs must be regarded as modest...Compared to the huge increase in accident risk associated with alcohol, as well as the high accident rate among young drivers, the increases in risk associated with the use of drugs are surprisingly small."" A report from the University of Colorado, Montana State University, and the University of Oregon found that on average, states that have legalized medical cannabis had a decrease in traffic-related fatalities by 8–11%. The researchers hypothesized "it’s just safer to drive under the influence of marijuana than it is drunk...Drunk drivers take more risk, they tend to go faster. They don’t realize how impaired they are. People who are under the influence of marijuana drive slower, they don’t take as many risks". Another consideration, they added, was the fact that users of mariju