Legalized marijuana linked to a sharp increase in car accidents

According to a pair of new studies, the number of road accidents has increased by 6%, in four of the states where the use of marijuana for recreational purposes has been legalized.

New reports do not prove that there is a direct risk associated with marijuana use among motorists, but they signal caution, especially since it is not easy to test drivers to find out if they are actually under the influence of THC. , the active ingredient in marijuana, said David Harkey, president of the Highway Loss Data Institute of the Insurance Institute for Highway Safety.

"It's definitely early in the game," Harkey told NBC News. But, he warned, "we are seeing a trend in the wrong direction."

At present, 30 states have legalized the use of marijuana for medical purposes, with Oklahoma being the newest to be on the list. Nine states and the District of Columbia have legalized recreational use. With a Gallup poll showing 64% public support, other states should follow, including Michigan, where recreational use is listed in the November newsletter.

Since the beginning of the wave of legalization, safety and health experts have been trying to measure the potential influence on road safety, although the results so far have been inconsistent and, in some cases, contradictory.

But for the second year in a row, the IIHS has seen a disturbing trend. A year ago, the nonprofit group reviewed three states, Colorado, Oregon, and Washington State. This year, Nevada has been added to the list. Harkey said that IIHS had also examined data on road accidents in neighboring states to control weather and economic factors.

The studies looked at police reports and insurance claims, and found that collisions had increased from 5.2% to 6% in states where marijuana was legalized compared to neighboring states, where this was still illegal.

The IIHS also conducted a study on marijuana use in the street and found something that Harkey said was of particular concern. While people under the influence of alcohol tend to drive alone or with other adults, about 14% of those who confirmed using jars had a child in their vehicle. This reflects the fact, he added, that marijuana use is not limited to evenings and other times when adults are more likely to drink – and abuse – alcohol.

What is unclear is whether this reflects the increasing use of recreational marijuana or medical marijuana to treat problems such as pain or glaucoma, which is a problem. patient may need.

Harkey warned that there are limits to what studies show. There is a "correlation", reflecting the fact that collisions have increased once the pot has become legal, but this is not the same as "causality", he added, this which means that other invisible factors could be at work.

This could help explain why previous studies have often focused on the effects of marijuana on road safety. One of them, published by the University of Colorado in 2014, revealed an increase in the number of deaths involving stoned drivers. But a study conducted by the National Highway Traffic Safety Administration in Virginia a year later revealed no clear increase in risk.

Part of the problem is that it is difficult to accurately measure the effect of the pot on the drivers. "Many studies, using various methods, have attempted to estimate the risk of driving after consuming marijuana," a NHTSA report to Congress reported last year. "Experimental and observational studies do not predict real-world collision risks, although they are useful in identifying the impact of marijuana on driving performance."

The police face a particularly difficult challenge because of the way marijuana works in the body. Blood alcohol levels provide a direct correlation showing the amount of alcohol consumed by a motorist, these rates decreasing rapidly as someone gets depressed. But while THC levels increase after having smoked the herb or consumed a consumable, the psychoactive ingredient remains in the body for weeks, long after it has stopped having an impact.

Mr Harkey said that regulators, law enforcement and medical authorities should tackle the "challenge" and come up with better ways of determining when a driver could drive under the radar. influence of marijuana.