A rite of October turned treacherous on Saturday when a car plowed into the back of a hayride carrying 12 adults about 50 miles west of Chicago, sending 11 people to local hospitals, three of them with serious injuries, the authorities said.

The collision happened at 5:37 p.m. local time on River Road near Plano, Ill., according to Chief Gregory Witek of the Little Rock-Fox Fire Protection District.

“The strike from the vehicle was hard enough that people were ejected from the wagon itself,” Chief Witek said in a phone interview Saturday night.

Video taken at the scene of the collision showed the car, a black sedan, flipped upside down on its roof next to the tractor that had been pulling the hayride.