The southbound lanes of I-375 at Lafayette in Detroit were closed briefly Friday morning for a crash.
Michigan State Police said a car hit the wall and a woman in a second car pulled over to help.
A third car hit one of the stopped cars, causing one to propel into the woman.
She was taken away in an ambulance. Police said she wasn't facing any life-threatening injuries.
Police said they are also investigating the third driver involved to see if alcohol was involved.