CNN Driving Stoned - video screencap

With multiple states legalizing marijuana, government agencies are scrambling to research the effect of the drug on drivers. CNN recently took a look at operating a motor vehicle under the influence of pot by subjecting three users in Washington state to a little driving test with the help of a local sheriff's department. The results are a little surprising, with even casual smokers able to safely operate a car with up to five times the state's new legal limit in their blood stream. At worst, the smokers were actually more cautious on the course than they were before partaking.

Once the levels increased, however, the story changed dramatically, with two participants showing obvious signs of impairment. Heavy user Addy, meanwhile, continued to perform admirably up until the very last stage of the study. You can check out the full video below for yourself, and remember to keep it off the road, kids.