Could marijuana legalization lead to an increase in car accidents ?

Two recent studies indicate that States that had legalized the recreational use of marijuana have seen a significant increase in car accidents compared to States that haven’t legalized marijuana for recreational use.  One of the studies was released by the Insurance Institute for Highway Safety (IIHS) and  the other one by the Highway Loss Data Institute (HLDI). These two studies were presented last week at the Combating Alcohol- and Drug-Impaired Driving Summit, that was hosted by IIHS and HLDI.  The study presented by HLDI looked at collision claims per insured vehicle in the Sates of  Colorado, Nevada, Oregon and Washington compared to the States of  Idaho, Montana, Utah and Wyoming from January 2012 to 2017. Researchers found that the frequency of collision claims per insured vehicle rose a combined 6 percent by year in the States that started the retail sale of Marijuana compared to the States where Marijuana is still a controlled substance. The study presented by IIHS compared the change in crash rate in Colorado, Oregon and Washington with neighboring States that didn’t enact recreational marijuana laws and found a 5.2% increase in the rate of crashes in States that authorized the recreational use of Marijuana compared to the States that didn’t authorize it.

The numbers found by both teams of researchers are consistent with each other however because the police still have no proper tool to detect if a driver was under the effect of Marijuana when involved in an accident it is difficult to prove that the legalization of marijuana make roads less safe.

While alcohol tests after an accident are pretty reliable, there are still no available tools to test if a marijuana user was impaired by the drug at the time of the accident. Because THC remains in the body for a long period of time after the substance is  consumed, a positive THC test doesn’t imply that the driver was high behind the wheels.