As legalizing and decriminalizing marijuana use becomes more widespread in the US, studies are being made to ascertain the effects of being high behind the wheel. The latest research suggests that while drivers who smoke dope are more likely to be involved in a traffic accident, it's not because of the drug itself. Released by the US government, the NHTSA said the study – the "most precisely controlled" of its kind conducted so far – did not find "a significant increase in levels of crash risk associated with the presence of drugs."

Variables such as age, gender, ethnicity and alcohol concentration level "were highly correlated with drug use and account for much of the increased risk associated with the use of illegal drugs and with THC." In short, if you smoke weed you are likely to be in the same demographic as those who tend to crash, which we assume are young males who like to party. Conducted in Virginia Beach, Va., the 20-month study included 3,000 drivers involved in crashes and 6,000 drivers who were not. Despite its findings, there's no doubt that smoking marijuana causes impairment, and driving under the influence is a bad idea.