ATLANTA --Atlanta's notoriously tangled commutes were thrown into disarray Friday after a massive fire caused a bridge on Interstate 85 to collapse, completely shutting down the heavily traveled highway through the heart of the city.
Traffic was bumper to bumper on nearby streets as people scrambled to find alternate routes after the fire broke out during rush hour Thursday afternoon. However, officials said no one was hurt despite dramatic images of towering flames and plumes of smoke.
"This is about as serious a transportation crisis as we can imagine," Atlanta Mayor Kasim Reed said.
As a result of the interstate damage, many commuters in some of Atlanta's densely populated northern suburbs will be forced to find alternate routes or ride public transit for the foreseeable future.
Georgia's top transportation official said there's no way to tell when the highway, which carries 250,000 cars a day, can be safely reopened to traffic in either direction following the collapse in the northbound lanes leading out of the city.
"We will have to continue to evaluate the situation and adjust as we do," Department of Transportation Commissioner Russell McMurry said. "This incident - make no bones about it - will have a tremendous impact on travel."
McMurry said Friday in a news release that bridge inspectors have determined the southbound lanes of I-85, adjacent to the section that collapsed, also were damaged by the fire and will need to remain closed for the foreseeable future.
He said the fire started in an area that was used as a storage location for construction materials, equipment and supplies. Authorities were still working to determine how the fire started.
The interstate is a major artery for the U.S. South and a thoroughfare for traffic heading north and south through Atlanta. The bridge collapse effectively "puts a cork in the bottle," Georgia State Patrol Commissioner Mark McDonough said.
For some motorists, Thursday's snarl brought back nightmares from a winter storm in January 2014 that left motorists stranded on interstates and highways overnight and children trapped on school buses.
Many motorists abandoned their cars and slept in convenience stores or restaurants that opened their doors to commuters seeking shelter.
Georgia Gov. Nathan Deal declared a state of emergency after the interstate collapse, saying the state is mobilizing resources to try to keep traffic disruption to a minimum while emergency work continues.
The Metropolitan Atlanta Rapid Transit Authority, or MARTA, increased rail service on Friday and will have additional staff on hand to help passengers figure out how to get where they're going.
It began with a fire that burned for more than an hour under I-85 northbound, spewing clouds of black smoke skyward. The interstate was closed indefinitely and the Department of Transportation warned all motorists to stay off I-85.
Rose Diggs told The Atlanta Journal-Constitution that she lives less than a mile from the fire site but couldn't get home because of blocked surface streets. She said she was told to walk despite being disabled, "but it's raining and dark."
Capt. Mark Perry of the Georgia State Patrol told the newspaper terrorism is not suspected.
Gov. Deal told reporters PVC plastic materials in a vehicle may have caught fire.
Atlanta Fire Department spokesman Sgt. Cortez Stafford said no cars were on the overpass when it fell.
"Our guys got here quickly and shut down the interstate and said, 'No one else is driving over this bridge,'" he said.