Tulsa, Okla. - It might be a prank, or it might be someone looking for a souvenir, but whatever it is, the Oklahoma Department of Transporation says the result is dangerous.
They say people are tampering with and even stealing highway signs.
They say it causes people to miss an exit, or in a worst-case scenairo, it could cause a fatal accident.
It's also expensive for taxpayers.
Depending on the size and location of the sign, replacing it can cost in the thousands of dollars.
ODOT is asking people to keep their eyes peeled for people tampering with signs and to call police if they see it happening.