The latest message? An electronic sign that warned "Caution: Zombie Stripper."

Hackers have hit construction signs around the country including the Denver metro area.

While the messages are often humorous, road crews are not laughing.

"It may be funny to them [hackers], but it is a real safety hazard to those that may be living in the area or traveling in the area," said Rick Bowman co-owner of Barricade & Sign.

His message for the culprits, "You may think it’s cute, but it will be your responsibility when somebody gets killed."

Bowman warns that drivers who see a sign changed should be extra careful driving in that area.