Some of the stumblers walking around Denver over the weekend had little, if anything, to do with all the St. Patrick’s Day festivities (photos from Westword). The third annual March of the Zombies fashion show took place Saturday, perhaps explaining another phenomenon in the region—hijacked highway signs. As a road-construction sign with Lite Brite-style lettering warned on Boulder’s Foothills Parkway yesterday: “Zombies Ahead” (Daily Camera). Signs across the nation have occasionally been heisted by hackers who add instructions to the messages, such as “Run!”

Though some find the situation funny, the Colorado Department of Transportation is tackling the problem with grave seriousness. After all, the sign in Boulder was supposed to say, “Shoulder work Feb. 28 through June” (7News). But someone gained access to the unlocked panel to change the message, and as a result highway workers are securing all the locks. The prank is rather rare. Traffic signs have been hacked about three times in the last decade, and the fine for tampering with a Colorado highway sign is $66.