ATLANTA (AP) - A major effect on traffic in a city already known for gridlock is expected after a massive fire caused a bridge on Interstate 85 to collapse in Atlanta.

Georgia's top transportation official says there's no way to tell when the highway can be safely reopened to traffic in either direction following the collapse, which happened Thursday afternoon during rush hour.

Department of Transportation Commissioner Russell McMurry says the collapse "will have a tremendous impact on travel."

The interstate is a major artery for the U.S. South and a thoroughfare for traffic heading north and south through Atlanta.

Traffic was bumper to bumper on nearby streets Thursday night as people scrambled to find alternate routes.

However, officials say no one was hurt despite dramatic images of towering flames and smoke.

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