The Colorado Department of Transportation has come up with a novel way to prevent mile marker 420 on Interstate 70 from getting stolen by marijuana enthusiasts.

420 is a popular “secret” reference to marijuana smoking, supposedly originating in San Rafael, Calif., as a way for teenagers to organize smoke sessions. It has grown into one of marijuana culture’s most recognized slang terms, and has found itself on hats, T-shirts, and just about anything else.

The Colorado DOT used a similar strategy to prevent a ‘MILE 69’ sign from getting stolen, using ‘MILE 68.5’ instead. "So far it's working," Amy Ford, a spokesperson with the Colorado Department of Transportation, told 9 News Colorado. "It's a traffic-safety thing. It's a helpful thing to have these signs on the road. But people kept ripping them off."

A photo of the sign first appeared on the popular Internet forum Reddit a year ago, but went viral only in the last week, likely due to Colorado’s recent legalization of recreational marijuana. Marijuana industry officials estimate that out-of-state visitors could make up to 30 percent of their recreational sales, so many enthusiasts will likely pass the ‘MILE 419.99’ marker as they travel to Denver.

Potential sign stealers may be disappointed that they’ll be unable to get a ‘MILE 420’ sign, but many online commenters have expressed they actually want a ‘MILE 419.99’ even more than a “MILE 420’. With the amount of attention it’s getting on the Internet, eyes will be on a small stretch of highway outside Stratton, Colo., to see how long it will last.