A police officer suffered a head injury when the patrol car he was driving collided with another vehicle at an intersection early Saturday morning. The officer — who has not been identified — was taken to a nearby hospital and is listed in fair condition, according to a police spokesman.

The 25-year-old man driving the other was also taken to a hospital and is in stable condition.

According to the Chicago Tribune, passengers on a nearby trolley came to the officer's aid.

"They were trying to get him to respond and he was not," said one witness.

"I think they were awesome," the woman said. "They did something I wasn’t able to do. … They got help for the officer."