Police said it all began when officers tried to pull over a BMW on Atlantic Avenue.
The investigation shut down the busy roadway for more than seven hours.
"It's chaos. It's pure chaos," one woman said.
Traffic came to a standstill, even delaying fire trucks from getting to an emergency.
"You can't get to Atlantic Avenue. You can't get to Flatbush. You can't do nothing. Police is not helping out. It's traffic, backed up," the woman added.
Sources told CBS2 police received a call about someone with a gun inside the BMW. They tried to pull the car over, but the driver kept going.
That's when someone in the car allegedly shot at the officers, and they fired back.
"I heard a gunshot. I think one or two shots. When I came outside, I heard cars spinning up the block," said witness Patrick Simpson.
Simpson owns a nearby restaurant and said people ran for cover inside.
"They look frightened. They were saying, 'There's a shooting outside. There's a shooting!'" he said.
On top of being rush hour, a concert in the area made traffic worse. Somehow with all those people around, no one was injured.
CBS2's Jessica Layton contributed to this report.
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