Photo: Michel Porro / Getty
Recreational marijuana has been legal in Colorado since 2014, but researchers hoping to study the effects of the drug on humans are restricted by federal law to government-grown marijuana, which is significantly weaker and less diverse than commercial weed.
A group of researchers from the University of Colorado Boulder created a loophole by buying a van — the CannaVan — and are traveling around the state to study the physical and mental effects of government-grown marijuana versus commercial marijuana products for sale at local dispensaries, according to WIRED.
How it works: Scientists assign participants particular commercial marijuana products with already-known chemical makeup and potency, which the subjects go out and purchase for themselves. The researchers go to the participants' homes and first perform tests while they are sober. They then measure the effects of the drug after it is smoked, eaten, vaped, etc. But the researchers never see the commercial product itself.
Precision: While the studies are not as precise as a normal lab study, they are as good as it gets given the legal restrictions on researchers.
Go deeper: WIRED's full piece and Sessions hints at federal crackdown on marijuana