(WBIR - Crossville) For the first time in more than 20 years, the world's longest yard sale will operate at the same time school students head back to the classroom.

The Highway 127 Yard Sale, which runs from Michigan to Alabama along the multi-state roadway, will start on August 7 and run through Sunday the 10. Schools in Cumberland County will have their first full day on August 8. Four of the county's schools are on Highway 127.

"A lot of the parents on the first few days drive their kids to school [sic] when later on they ride the bus," said Cumberland County Sheriff Butch Burgess. So, he plans for extra patrols to monitor the 20-mile stretch that runs through his jurisdiction. "It's just a high volume traffic, besides the yard sale."

He's warning the public, especially drivers who are not familiar with Cumberland County roads, to watch not the sales on the side of the streets, but what's in front of them too.

"We got a lot of people who are not familiar with the roads, where the schools [are]," he said. "So we're going to have our plates full."

Donald Andrews, the Superintendent of Cumberland County Schools said a letter will be sent home with parents Wednesday when students have a half day of class, warning them about the impending traffic.

Sheriff Burgess said it's about staying alert behind the wheel.

"You have to stay slow enough that you can stop your car when a little child runs out between the car. You know, we've actually had that happen to us," the sheriff said.