Why Colorado Once Had to Replace a Road Sign That Read “420”

July 16, 2021

A 420 mileage marker sign that was replaced with a 419.99 mile marker sign.

In 2014, the State of Colorado responded to a repeated problem of people stealing a particular number on a mile marker sign along an interstate. 

The Colorado Department of Transportation switched mile marker “420” to “419.99” on Interstate 70 east of Denver because there had been multiple thefts of the “420” sign. The Colorado Department of Transportation said the sign had been changed sometime during 2014 because of the thefts.

Why was there a rash of thefts on the sign? It’s believed (and probably pretty certain) to be because the number 420 is associated with smoking cannabis, which is also known as marijuana, weed, ganja, reefer, or hashish, at the time of 4:20 PM. It’s also a day of cannabis celebration on April 20th or 4/20. 

The origins of the number aren’t accurately known, but it is believed to either have been started by teenagers in the 1970s who met to smoke marijuana at 4:20 PM or was from a mistaken police code for someone smoking marijuana. It became apparent to the transportation department why the sign was continually stolen, however. The “419.99” sign was actually placed 50 feet from the spot the old sign stood, so the location was still accurate.

The Colorado Department of Transportation cited the safety need for the mileage signs being in place as they are intended to be a reporting point for motorists involved in an accident or having some other type of problem. It also cost the state money in replacement costs and labor for continually having to replace the signs.

Colorado hasn’t been the only state that has faced this problem. The State of Washington had a problem with the theft of a “420” mile marker and replaced the sign with “419.9” in 2019. The State of Idaho also has had issues with thefts of “420” mileage marker signs. But the “420” sign hasn’t been the only numbered sign to get stolen in these states.

The Washington Department of Transportation also had to replace a “69” mile marker (most will know what that refers to) to “68.9” due to multiple thefts on Route 231 in eastern Washington, and Colorado had to replace a sign “68.5” due to thefts of the “69” mileage marker. For the case in Washington, the “68.9” sign was even stolen, replaced, and then stolen again. 

The State of Washington has been dealing with the theft of “420” and “69” mileage marker sign thefts for the past 20 years, and the department has gone as far as installing a steel post in concrete for one sign (which someone yanked out with a vehicle) to putting up a blank sign at one point between mileage marker signs 68 and 70. It seems people can’t stay away from stealing these numbered signs.

Sources: Denver Post, NY Daily News, The New York Times 

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Daniel Ganninger - The writer, editor, and chief lackey of Knowledge Stew, the author of the Knowledge Stew line of trivia books, and editor of Fact World and the Knowledge Stew sister site on Medium, our ad-free subscription sites (you can find out how to join below). I hope you find things here to annoy those around you with your new found knowledge.

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