The video shows two men jumping out of a car in stopped traffic in the Chatham area of the city before opening fire at a vehicle ahead of them.
It was all captured by a camera in the car of witness Huber Pereznegron.
“I saw a man getting off the backseat with a rifle,” Mr Pereznegron told CBS Chicago.
“I didn’t think it was real, so I didn’t think much about it until a second person came out. Then I saw him with another gun.”
After the shooting both men jumped back into the Red Nissan car and fled the scene.
Police responded to the incident after they were alerted by the ShotSpotter system used by law enforcement.
No injuries have been reported and no arrests have yet been made, but a car and a local business were damaged.
Mr Pereznegron said he was amazed that no one was killed in the incident.
“They don’t care who sees them or what they do when they go out,” he said.
“I don’t know what’s going on in their minds. This must be stopped. There were a lot of innocent people around them.”