The Minnesota Department of Transportation in June tapped into the Taylor Swift hysteria ahead of her Twin Cities concerts by posting a message on its electronic signs that read "Cut off? Don't Get Bad Blood. Shake it Off."

The nod to Swift's pop hit is the kind of lighthearted message MnDOT has been using for more than a decade each Monday to encourage safe driving.

Now federal authorities want the jokes, slogans and quirky sayings often drawn from movies, TV shows, music and other slices of pop culture to stop.

New directives from the Federal Highway Administration call for traffic safety messages to be "simple, direct, brief and clear" because nonstandard messages like MnDOT's can be "misunderstood or understood only by a limited segment of road users."

States such as Minnesota have two years to comply with the changes included in the 1,100-page manual, which sets national standards for use of traffic control devices, including changeable message boards. The revised manual was updated last month and goes into effect Thursday.

Despite the order from Washington, MnDOT says it will still be business as usual, and the practice of displaying weekly pithy traffic safety messages on overhead and roadside digital signs will continue.

"We do not anticipate (the new directives) will change the way MnDOT shares creative highway safety messages with the public that helps improve safety on our Minnesota roadways," said spokeswoman Anne Meyer.

Before "Message Monday," MnDOT used its electronic message boards sparingly to display messages such as "1 in 4 Deaths Caused by Drunken Drivers" and "1 in 5 Traffic Deaths are Speed Related." But when traffic fatalities failed to drop, the agency instituted "Message Monday" as a way to deliver hard hitting messages — to wear seat belts, obey speed limits and not drive impaired — with a lighter, more positive tone.

MnDOT owns and operates the signs.

The changes at the federal level garnered support from the Minnesota Department of Public Safety.

"We respect and agree with the changes they are making in regards to the use of these important public messaging tools," said Mike Hanson, director of the Department of Public Safety's Office of Traffic Safety. "The ultimate goal is to improve traffic safety as a result of effective signage policies."