Thursday, May 25, 2017

Summary of effects of marijuana on driving performance.

Excerpt from 2009 research...

Although cognitive studies suggest that cannabis use may lead to unsafe driving, experimental studies have suggested that it can have the opposite effect. Epidemiological studies have themselves been inconsistent, and thus have not resolved the question.

One possibility is that people who smoke marijuana share qualities—being young, male, and risk-taking—that would increase their risk of road traffic accidents even in the absence of marijuana use. It has been suggested that there is a single factor that underlies adolescent “problem behaviors” such as illicit drug use, precocious sexual intercourse, and problem drinking.

Two epidemiological studies in New Zealand that attempted to address this hypothesis found that the significant relationship that existed between self-reported cannabis use and self-reported accidents disappeared after risky driver behaviors and unsafe driver attitudes were controlled for. A follow-up study found that the crash risk for driving under the influence of cannabis more than 20 times in one year was halved and reduced to marginal significance when distance driven and self-reported risky driving behaviors were controlled for.

A third Canadian study that compared crash rates in cannabis users found an even higher adjusted OR of 2.61 for crashing over the course of the year in those who drove while “stoned” versus marijuana smokers who did not, suggesting that the decision to drive while intoxicated may predict poor judgment and unsafe driving habits even in the absence of marijuana use.

In summary, laboratory tests and driving studies show that cannabis may acutely impair several driving-related skills in a dose-related fashion, but that the effects between individuals vary more than they do with alcohol because of tolerance, differences in smoking technique, and different absorptions of THC.

Driving and simulator studies show that detrimental effects vary in a dose-related fashion, and are more pronounced with highly automatic driving functions, but more complex tasks that require conscious control are less affected, which is the opposite pattern from that seen with alcohol.

Because of both this and an increased awareness that they are impaired, marijuana smokers tend to compensate effectively for their impairment by utilizing a variety of behavioral strategies such as driving more slowly, passing less, and leaving more space between themselves and cars in front of them.

Combining marijuana with alcohol eliminates the ability to use such strategies effectively, however, and results in impairment even at doses that would be insignificant were they of either drug alone.

Case-control studies are inconsistent, but suggest that while low concentrations of THC do not increase the rate of accidents, and may even decrease them, serum concentrations of THC higher than 5 ng/mL are associated with an increased risk of accidents.

Overall, though, case-control and culpability studies have been inconclusive, a determination reached by several other recent reviewers.
Similar disagreement has never existed in the literature on alcohol use and crash risk.


420 Friendly Holiday Appartments in Sunny Andalucia SPain, near Malaga.

Hempy Holidays Apartments (5 of them), with private kitchen and terrace, for a relaxing holiday near Malaga in sunny Andalusia. (Only Pro-smoking for over 18 years.)

The theme of hemp is not only in the name, the apartments, the garden and pool are also provided with decoration and information of hemp. Private parking.

Rates; from may to September: 75 € / 85 $ per apartment per day / night, 1-2 people.

Alora Village, near to the reservoirs of the stream and the famous "Caminito Del Rey"
40 km from malaga airport.

Search This Blog

Find MrLunk on Facebook


Last 30 days: