Monroe County authorities are on scene of at least 25 car accidents Wednesday morning, Michigan State Police said.
Wrecks are reported on I-75, U.S. 23, and Telegraph Road, though none involve major injuries, Trooper Sharon McDonald said.
"I think it's black ice," she said. "It's basically the main streets that are having all the problems."
One of the minor crashes involved a school bus in Monroe. No children were hurt, police said.