Can THC affect driving skills ?

Is there a higher risk of traffic accidents after consuming THC ?

Scientific circles are divided on the issue of increased risk of accidents when driving under the influence of cannabis. Several studies have shown an increased risk associated with cannabis use by drivers, other studies have not found an increased risk. In a large-scale study conducted by the National Highway Traffic Safety Administration and by the American Automobile Association shows that drivers are no more likely to cause accidents after using THC than drivers who have not consumed THC. There is no correlation between the amount of THC in the blood and the degree of impairment. No known association between levels of THC in blood and an increased relative risk of an accident, or between levels of THC and the degree of impairment in driving ability, has been found.

A large review of 66 studies on crash risk and drug use found that cannabis is associated with a small but not statistically significant increased likelihood of injury or fatal crashes.

Fatal crash odds while driving under the influence of cannabis compared to other drugs :

• cannabis 1.26
• opiates 1.68
• antianxiety medications 2.30
• zopiclone (sleep drug) 2.60
• cocaine 2.96
• amphetamines 5.17

Chances of injury while driving under the influence of cannabis compared to other drugs :

• cannabis 1.10
• antihistamines 1.12
• penicillin 1.12
• antianxiety meds 1.17
• antidepressants 1.35
• antiasthmatics 1.31
• zopiclone (sleep drug) 1.42
• cocaine 1.66
• opiates 1.91

The study reached the following conclusion: Compared to the massive increase in accident risk associated with alcohol and the high accident rate among young drivers, the increase in risk associated with drug use is shockingly small. A report by three US universities (Colorado, Montana and Oregon) found that states that have legalised medical cannabis have seen an average decrease in traffic deaths of 8-11%. They hypothesized that driving under the influence of marijuana is safer than driving under the influence of alcohol. Drunk drivers take more risks, tend to drive faster. They don’t realize how impaired they are. People that are under the influence of marijuana drive slower, they don’t take as many risks.

Does cannabis impair any driving skills ?

It is possible that cannabis impairs driving, but there are currently no reliable means of testing or measuring whether a driver has actually been affected by cannabis. The UK Department for Transport reviewed data on cannabis and driving and found that cannabis impairs driver behaviour. However, this impairment is mediated by the fact that cannabis-treated individuals seem to perceive that they are actually impaired and are able to compensate. The effects on driver behaviour are present for up to an hour after smoking but do not persist for long periods of time. The review also identified young men, among whom cannabis use is common and among whom alcohol consumption is also common, as a high-risk group for traffic accidents. The cause, according to the report, is inexperience in driving and factors associated with youth that relate to risk-taking, delinquency and motivation. These demographic and psychosocial factors may be related to both drug use and crash risk, thus representing an artificial relationship between drug use and crash involvement. The review did not target only drivers under the influence of THC, so caffeine users would have ended up with the same conclusion.

Laboratory studies examining the effects of cannabis on skills used in driving show impairments in tracking, attention, reaction time, short-term memory, hand-eye coordination, alertness, time and distance perception, and decision-making and concentration concluded that the acute effect of moderate and higher doses of cannabis impairs skills related to safe driving and injury risk, specifically attention, tracking, and psychomotor skills. However, it is important to note that laboratory tests do not reflect the reality on the road. Unlike alcohol,cocaine or meth, most drivers under the influence of cannabis are aware of their impairments and try to compensate them by paying more attention and prefer to drive slower, giving them plenty of time to react. Of course this is a very individual problem, definitely don’t get a ride from a stoned beginner driver or someone whose car looks like the car in the picture to the right. And if you’re a new driver, you should definitely avoid driving under the effect of marijuana.

Do roadside tests for THC make any sense at all?

The problem with the tests is that they do not distinguish between the level of THC in the blood and the fact that the metabolisation of THC is very long. So THC presence in blood may have absolutely no effect and yet the driver is persecuted. Alcohol tests are accurate and there is a direct parallel between the amount of alcohol in the blood and the actual effect on the mind and body. By contrast, tests for cannabis are incomparable in this sense and therefore responsible and innocent drivers are persecuted. If it is suspected that a driver is unfit to drive as a result of cannabis ingestion, tests for the presence of the metabolite should not be used, but always a medical examination.

Summary on driving under the effect of THC

Cannabis, or THC, cannot affect you enough to be considered dangerous when driving. It is the same as millions of people taking drugs that more or less affect their ability to drive. However, laws around the world ignore this fact and give unfairly draconian penalties to those negligible or only metabolizing THC in their blood.

Testing for THC is as ridiculous and irrelevant as testing for antihistamines (allergy medications), which affect the ability to drive more than cannabis.

Based on source : Wikipedia