Cannabis companies are using a loophole in Colorado’s strict limits on marijuana advertising by sponsoring state highways and putting their names on roadside signs.

Currently, 51 cannabis dispensaries, cultivators, manufacturers and edible producers sponsor roadways throughout the state, according to the Adopt a Highway Maintenance Corporation. Although they represent less than half of all organizations that participate in the Clean Colorado program, their reach spans about 198 miles, or 66%, of the roads actively sponsored, The Denver Post reported.

“The rules governing highways signs are in a different section than rules governing the cannabis industry,” said Nico Pento, government affairs director for Boulder-based Terrapin Care Station, which operates six dispensaries in the Denver metro area. “The highway signs were a loophole that was overlooked.”

Colorado Department of Transportation officials say the signs are not intended to be an advertising medium, but they have become a clever workaround for an industry with few other options. Oftentimes, they are strategically placed near exits where passersby can find the businesses.

Colorado’s rules governing how and where cannabis companies can advertise are strict to prevent marketing messages from reaching minors. [Read more at Oregon Live]